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Vaccine Adverse Event Reporting System (VAERS)

Vaccine Adverse Event Reporting System Summary

Summary:    The Vaccine Adverse Event Reporting System is a cooperative program for vaccine safety of the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA). VAERS is a post-marketing safety surveillance program, collecting information about adverse events (possible side effects) that occur after the administration of US licensed vaccines. This online database provides a nationwide mechanism by which these reports may be analyzed and made available to the public. The data are updated monthly and include reports received through the last Friday of the previous month. See the Vaccine Adverse Event Reporting System (VAERS) web site for more information.

DISCLAIMER:   VAERS staff at CDC and the Food and Drug Administration (FDA) follow up on all serious adverse event reports to obtain additional medical, laboratory, and/or autopsy records to help understand the circumstances. However, VAERS public data do not generally change based on the information obtained during the follow-up process.

There are limitations to VAERS data. A report to VAERS does not mean that the vaccine caused the adverse event, only that the adverse event occurred sometime after vaccination. Read more about interpreting VAERS data at Additional Information: Data Limitations.

Incidence:   Reports of adverse events following immunization (AEFI) submitted to the Vaccine Adverse Event Reporting System. Event characteristics include symptoms reported, vaccine type, name and manufacturer, number of days between vaccination and the adverse event, vaccination date, report date, whether the event was considered serious, how the event outcome was categorized, whether the patient recovered, and the patient's age group, gender and home state.

Population:   All persons reported as having experienced adverse events after vaccination, reports received in June 1990 through last month. The earliest vaccination date in the reports is December 1901. Reports are updated monthly and include reports received through the last Friday of the previous month. All reports are included, including recent reports of adverse events in previous time periods.

Source:    Department of Health and Human Services (DHHS), Public Health Service (PHS), Food and Drug Administration (FDA)/ Centers for Disease Control (CDC), Vaccine Adverse Event Reporting System (VAERS).
In WONDER:    You can produce tables, maps, charts, and data extracts. Obtain frequency counts for event reports, and show the percentage of unique events. Display the Event Details reported for any single event, or the text from the Adverse Event Description, Lab Data, Current Illness, Adverse Events After Prior Vaccinations, Medications At Time Of Vaccination, and History fields. Select specific event, vaccine and demographic criteria to produce cross-tabulated incidence measures. You can limit and index your data by any and all of these variables:

VAERS Data Items

    Person and Place
  1. Age
  2. Gender
  3. State / Territory
    Event Characteristics:
  4. Symptoms - classified with Medical Dictionary for Regulatory Activities (MedRA).
  5. Event Category - describes the outcome of the event.
  6. Recovered - indicates if the patient recovered fully.
  7. Serious - indicates whether event was classed as serious. `
  8. Onset Interval - number of days after vaccine when symptoms occurred.
  9. Vaccine Administered By - public, private, other, military, unknown agency.
  10. Vaccine Purchased By - public, private, other, military, unknown agency.
  11. Grantee - places receiving grants, when applicable.
  12. VAERS ID - unique identification number for this event. Leave empty for all events.
  13. Previous VAERS ID - previous ID for this event, if any. Leave empty for all.
  14. Mfr/Imm Proj Num - Manufacturer/Immunization Project Number, when applicable. Leave empty for all.
    Vaccine Characteristics:
  15. Vaccine Products - vaccine type and name.
  16. Manufacturers - makers of vaccine products.
  17. Vaccine Dose - the number of vaccine doses given for a vaccine.
  18. Vaccine Lot - the lot number for a vaccine product.
    Text fields from the VAERS form:
  19. Adverse Event Description,
  20. Lab Data,
  21. Current Illness,
  22. Adverse Events After Prior Vaccinations,
  23. Medications At Time Of Vaccination,
  24. History fields.
    Date Characteristics:
  25. Year and month vaccinated
  26. Year and month reported
  27. Year and month report was received
  28. Year and month of onset of adverse event
  29. Year and month of death

Please refer to the following topics:


VAERS Data Request

`
Output:    You can produce tables, maps, charts, and data extracts. The output includes incidence counts of event reports and the percentage of unique events. As an option, you can choose to include the Adverse Event Descriptions for each event.

Variables:    You can limit and index your data by any and all of the variables.
How?    The Request screen has sections to guide you through the making a data request as step-by-step process. However, to get your first taste of how the system works, you might want to simply press any Send button, and execute the default data request. The data results for your query appear on the Table screen. After you get your data results, try the Chart and Map screens. Or export your data to a file (tab-delimited line listing) for download to your computer.

For more information, see the following:

Quick Start Guide
Step 1: Organize table layout;
Step 2: Select symptoms;
Step 3: Select vaccine characteristics;
Step 4: Select location, age and gender;
Step 5: Select other event characteristics;
Step 6: Search text fields;
Step 7: Select dates for when the event was reported;
Step 8: Select dates for when the report was received;
Step 9: Select vaccination dates;
Step 10: Select dates for the onset of the adverse health event;
Step 11: Select dates of death;
Step 12: Other options.

'By-Variables'    Select variables that serve as keys (indexes) for organizing your data. See How do I organize my data? for more information.
Note:    To map your data, you must select at least one geographical location as a "By-Variable" for grouping your data, such as State.
Help:    Click on any button labeled "Help", located to the right hand side of the screen at the top of each section. Or click on any label, such as the "Group Results By" label.
Send:    Sends your data request to be processed on the CDC WONDER databases. The Send buttons are located on the bottom of the Request page, and also in the upper right corner of each section, for easy access.



Step 1. Organize table layout:

Group Results By   Select up to five variables that serve as keys for grouping your data. See Group Results By below for hints.
Title   Enter any desired description to display as a title with your results.

The following measures are available as query results:

  1. Counts
  2. Percentages
  3. Adverse Event Descriptions


Group Results By...

Select up to five variables that serve as keys for grouping your data. For example, you could select to group (summarize, stratify, index) your data by Year Vaccinated and by Serious, to compare each year's number of serious and non-serious reports.

How?   

Hints:   

  1. The default measures are counts and percent of total. The total number of events that match your query criteria is also shown on the Results tab, in the messages area above the table.
  2. About the optional measures:
    Check the boxes under Optional Measures in section 1 on the Request tab, if you wish to output the entries from the text fields in the VAERS report form. You must group results by VAERS ID when requesting any of the optional measures. When you do so, the counts and percentages are disabled by default. You can show the counts and percentages by using the "Quick options" menu on the Results tab. About charts:
    You cannot make charts when your data has more than two By-Variables.
  3. About maps:
    To make a map, you must request data with a geographic location variable, such as State, as a "By-Variable." Then click the Map tab.

Events Reported

The Events Reported column shows the summary count or the frequency incidence of the selected categories in the data request. For example, when data are grouped by Symptoms, then the Events Reported column shows the number of times a specific symptom occurs in the reports included in the data request, which is not to say that this is the number of persons affected by the symptom, nor the total number of unique events. This is number of times the specific symptom is mentioned in event reports.

Notes:  

  • Events and reports are not the same. For example, a single event has one "primary" or initial report, and may also have several subsequent or follow-up reports. Since January 2011, only primary reports are included in the data.
  • Some items may have more than 1 occurrence in any single event report, such as Symptoms, Vaccine Products, Manufacturers and Event Categories. If data are grouped by any of these items, then the number in the Events Reported column may exceed the total number of unique events. If percentages are shown, then the associated percentage of total unique event reports will exceed 100% in such cases. For example, the number of Symptoms mentioned is likely to exceed the number of events reported, because many reports include more than 1 Symptom. When more than 1 Symptom occurs in a single report, then the percentage of Symptoms to unique events is more than 100%. For more information, see Multiple Mentions.


Percentages

The Percent column shows the percentage of this row's cases in comparison to the total number of unique events in your query. The number of unique events is shown in the column title.

Notes:  

  • Percentages may exceed 100% of the total number of unique events. For example, the number of Symptoms mentioned is likely to exceed the number of events reported, because many reports include more than 1 Symptom. When more than 1 Symptom occurs in a single report, then the percentage of Symptoms to unique events is more than 100%. Items that may have multiple occurrences in any single Event report include Symptoms, Vaccine Products, Manufacturers and Event Categories. When data are grouped by these items, then the summary totals and associated percentages may exceed the number of unique events. For more information, see Multiple Mentions.


Optional Measures

Check the box in Section 1 with your Mouse of Spacebar key to display the narrative text entries submitted with each event report. Group results by VAERS ID when requesting optional measures. The optional measures include these text fields:

  1. Adverse Event Description
  2. Lab Data
  3. Current Illness
  4. Adverse Events After Prior Vaccinations
  5. Medications At Time Of Vaccination
  6. History fields.

Hints:

  • You must group by VAERS ID when you select any optional measure.
  • When optional measures are shown, the counts and percentages are disabled by default. You can show the counts and percentages by using the "Quick options" menu on the Results tab.
  • The limit for the number of rows returned in any single results set is lower when the results include any optional text fields, due to the size of these fields. Each field may contain up to 2080 characters. The current limit for results with optional measures is 10,000 rows. If your request exceeds the limit, you can try to narrow the criteria. For example, run separate queries for each desired year of data, or for each gender.


Step 2. Select symptoms:

Symptoms

Select specific symptoms for the query. The coding of VAERS reports requires careful interpretation. All narrative text taken from original VAERS reports are classified with Medical Dictionary for Regulatory Activities (MedRA) concepts. Symptoms represent the medical condition(s) described in the case reports.

How?  
  • Select symptoms describing adverse reactions. The default selection is all symptoms.
  • You can search for a matching word and view details describing the symptoms associated with a specific MedRA code. See "How do I use a Finder?" for help.
    Hints:
    • Click the Search tab above the list of symptoms to search.
    • After you select an item in the list, click the Details tab above the list to see details for the selected item(s).
    • Leave box empty, or use *All*, to select all values.
  • Click the "Advanced Finder Options" link for more complex searches. The link is above the list of symptoms. The "Advanced Finder" lets you look for VAERS events with any mention of symptoms in a group, AND any mention of symptoms in another group. There is no limit to the number of items in each group. You can specify up to 5 groups. For example, you may wish to find events with any mention of fever and rash.
    1. Use the top "Move" button to put terms for fever in the top box under the "Select Records" section at the left.
    2. Use the 2nd "Move" button to put terms for rash in the 2nd box, labeled "AND any of these items."
    3. If you wish to add another group, click the "Add Another Section" button below the boxes.
  • If you happen to know a symptom code, then you may:
    1. Click the link for Advanced mode (if JavaScript is enabled).
    2. Type the code into the Selections box, one code per each line. You can also paste text into the boxes.
  • See Finder Tool help for more hints.
Notes:
  1. Each event report may be assigned multiple MedRA codes, representing the symptoms described.
  2. Careful interpretation of the assigned codes is recommended. Use the Finder's Search feature to find all codes associated with your interest, by searching the text in both the label and the description.
    • For example, a report coded for "Infection Bacterial" may not also be coded for "Infection," thus a requests for all of the reports with the "Infection" code value INFECT will not include those reports only coded to the value INFECT_BACT.
    • Symptom codes are unique, yet the labels and the descriptions are not unique. Click the Details tab in the Finder to see the distinctions. For example, the following Symptom labels have two different codes:
      1. Label:  FUNNY FEELING
        1. Code:   LIGHTHEADEDNESS_[IN_CONTEXT]
          Description:   FUNNY FEELING
        2. Code:   MALAISE_[IN_CONTEXT]; Description:   FUNNY FEELING
      2. Label:  FEVER
        1. Code:  FEVER
          Description:   DRUG FEVER, FEBRILE REACTION, FEVER, FEVER NEONATAL, HEAT PRODUCTION INCREASED, HYPERPYREXIA, HYPERTHERMIA, PYREXIA, REACTION FEBRILE, TEMPERATURE, TEMPERATURE ELEVATION
        2. Code:  CONVULSIONS; Description:   FEVER
      3. Label:   HEPATIC NEOPLASIA
        1. Code:   NEOPL_LIVER
          Description:   ADENOMA LIVER, HEPATIC NEOPLASM, HEPATIC NEOPLASM BENIGN, LIVER TUMOR, NEOPLASM LIVER, TUMOR LIVER
        2. Code:   CARCINOMA_LIVER
          Description:  CARCINOMA LIVER, LIVER CARCINOMA
  3. The universe of possible symptoms may change with each data update, to include new symptoms that were not previously reported. To see the universe of symptoms at a given point in time, group the data request by Symptom.
  4. When the data are exported, separate columns show both the symptom label and the MedRA code for each value.
  5. Note that the Finder's Expand and Collapse buttons have no effect, because the Symptoms classification list has only 1 hierarchical level.
  6. Prior to the March 2007 release on WONDER, symptoms were coded in the VAERS database utilizing the FDA's Coding Symbols for a Thesaurus of Adverse Reaction Terms (COSTART) classification system. COSTART classification was replaced by MedRA classification for all event reports in the March 2007 release.

Step 3. Select vaccine characteristics:

Limit your data to the selected categories, if desired:

  1. Vaccine Products - vaccine type and vaccine.
  2. Manufacturers - makers of vaccine products.
  3. Vaccine Dose - the number of vaccine doses given for a vaccine.
  4. Vaccine Lot - the manufacturer's lot number for a vaccine product.


Vaccine Products

Select specific vaccine types and names for the query. These products are organized by Vaccine Type, select an item from the first list of Vaccine Types, then click the Expand button in the Finder to see the vaccine names for this type of vaccine.

How?  
  • Select vaccine types and specific names. The top or first level of the hierarchy are the Vaccine Types. See "How do I use a Finder?" for help.
  • Click the Search tab and type in a word or phrase to find matching vaccine types and names.
  • If you happen to know a code for either Vaccine Type or Vaccine, then click the Advanced mode, and simply type the code into the box, one code per each line. (Advanced mode is only available when JavaScript is enabled.)
  • See Finder Tool help for more hints.
Notes:
  • Each event report may be assigned multiple vaccine products, because the patient may have received more than one vaccination before the adverse event occurred.
  • The universe of possible vaccine products may change with each data update, to include new vaccine types and vaccines that were not previously reported. To see the universe of vaccine products at a given point in time, group the data request by Vaccine Type and by Vaccine.
  • Effective with the November 2012 release of reports processed through October 14, 2012, the vaccine names and codes have been revised in the data, resulting in 128 fewer vaccines. Flu vaccines are now listed only by brand name, and the names no longer mention the specific flu season formulation. If you wish to search for reports for by flu season, please limit or group by Date Vaccinated.
  • When the data are exported, separate columns show both the label and the code for each value.


Manufacturers

Select vaccine product manufacturers for the query. Your data are limited to the selected criteria.

How?   See "How do I select items from the list box?" for help using the list boxes.
Notes:
  • Each event report may be assigned multiple vaccine products and thus manufacturers, because the patient may have received more than one vaccination before the adverse event occurred.
  • The universe of possible vaccine manufacturers may change with each data update, to include new manufacturers that were not previously reported. To see the universe of vaccine manufacturers at a given point in time, group the data request by manufacturer.
  • When the data are exported, separate columns show both the label and the code for each value.


Vaccine Dose

Select the categories for vaccine doses for the query. Your data are limited to the selected criteria. The categories are 0 doses, 1 dose, 2 doses, etcetera through "11 or more doses" and "Unknown."

How?   See "How do I select items from the list box?" for help using the list boxes.
Notes:
  • Each event report may include multiple vaccine products and thus multiple vaccine dose values, because the patient may have received more than one vaccination before the adverse event occurred.
  • Each vaccine indicated in the event report has a specific number of doses. Group results by Vaccine Product and by Vaccine Dose to see this association. To see the association for each event, group results by VAERS ID, Vaccine Product and Vaccine Doses.
  • When the data are exported, separate columns show both the label and the code for each value.


Vaccine Lot

Limit your data to the specified manufacturer's vaccine lot number(s).

How?  
  • Type full or partial identifiers, one per line, into the box, to request data limited to events with matching Vaccine Lot Numbers.
  • Leave the box blank for all events.
  • Type "NONE" to limit data to those events without a Vaccine Lot number.

Notes:
  • Each event report may include multiple vaccine lot numbers, because the patient may have received more than one vaccination before the adverse event occurred.
  • The vaccine lot numbers are not unique. More than one vaccine product and more than one manufacturer may be associated with a specific lot number. For example, Vaccine Lot Numbers 0745B and 0758K are each associated with events that indicate both POLIO VIRUS, ORAL (ORIMUNE) made by LEDERLE LABORATORIES and VARICELLA (VARIVAX) made by MERCK & CO. INC. Vaccine Lot Numbers 0970R, 1008M and 1180H are each associated with 2 different vaccines, MEASLES + MUMPS + RUBELLA (MMR II) and MEASLES + MUMPS + RUBELLA (VIRIVAC) made by a single manufacturer, MERCK & CO. INC.
  • To see the vaccine lot numbers associated with a specific vaccine product and manufacturer, group results by lot number, manufacturer and vaccine. There are over 88,000 distinct lot numbers, so you should also limit your query criteria in some other respect, such as specifying place or time period.
  • You can also type "NONE" to limit your data to those events where no lot number was indicated.
  • Some events have specified "unknown" in the Vaccine Lot Number box. These events are shown as reported with "unknown" and not recoded to show "NONE" as the value.

Step 4. Select location, age, and gender:
  1. State / Territory
  2. Age
  3. Gender
How?

State / Territory

Select the location(s) that represent the patient's home state. Any number of locations can be specified here.

How?   See How do I select items from the list box? to select specific options in the list.

Notes:  

  1. The "United States, Territories and Unknown" group includes all of the location values, except for "Foreign" locations. Before the December 17, 2009 data release, this group was named "United States and Territories" and the group excluded both "Unknown" and "Foreign" locations.
  2. "Foreign" reports represent patients from any location other than those included in those list.
  3. "Unknown" locations were not reported.
  4. The patient's home state is from box 1 on the VAERS reporting form.
  5. When the data are exported, separate columns show both the label and the code for each value. These labels and codes are in VAERS-Locations.txt, a simple text file with tab-separated values that can be opened as a spreadsheet.

Age

Select All Ages or any combination of values to request data limited to the selections for the patient's age group at the time of vaccination.

How?   See How do I select items from the list box? to select specific options in the list.

Notes:  

  1. Age group at time of vaccination is determined by subtracting the patient's birth date. from the vaccination date.
  2. When the data are exported, separate columns show both the label and the code for each value. These labels and codes are:
    Code    Label
    0 < 6 months
    1 6-11 months
    1-2 1-2 years
    3-5 3-5 years
    6-17 6-17 years
    18-29 18-29 years
    30-39 30-39 years
    40-49 40-49 years
    50-59 50-59 years
    60-64 60-64 years
    65+9 65+ years
    U Unknown


Gender

Select All Genders or any combination of values to request data limited to the selections for the patient's age group at the time of vaccination.

How?   See How do I select items from the list box? to select specific options in the list.

Notes:   When the data are exported, separate columns show both the label and the code for each value. These labels and codes are:


Code    Label
F Female
M Male
U Unknown


Step 5. Select other event characteristics:
Limit your data results to the selected query criteria:
  1. Event Category - describes the outcome of the event.
  2. Recovered - indicates if the patient recovered fully.
  3. Onset Interval - number of days after vaccine when symptoms occurred.
  4. Serious - indicates whether event was classed as serious.
  5. Vaccine Administered By - public, private, other, military, unknown agency.
  6. Vaccine Purchased By - public, private, other, military, unknown agency.
  7. Grantee - places receiving grants, when applicable.
  8. VAERS ID - unique identification number for this event. Leave empty for all events.
  9. Previous VAERS ID - previous ID for this event, if any. Leave empty for all.
  10. Mfr/Imm Proj Num - Manufacturer/Immunization Project Number, when applicable. Leave empty for all.
How?
  • See "How do I select items from the list box?" for help using the list boxes.
  • Only Primary Reports are shown (not additional or follow-up reports for the same event).
  • To request data only for specific events, type full or partial VAERS IDs, one per line, into the VAERS ID box. You can send a request grouped by VAERS ID in order to see the unique event identification numbers.

Event Category

The outcome of the event is categorized into one or more of the following options: death, permanent disability, life threatening reaction, hospitalization, prolonged hospitalization, emergency room visit and not serious. Select data from all events, or any combination of those options.

How?   See How do I select items from the list box? to select specific options in the list.
Notes:  
  1. When the data are grouped by Event Category, then the number of categories mentioned in the Events Reported column is likely to exceed the number of unique events. because a single event may fall into more than category. For example, a single report may mention an emergency room visit and a life threatening reaction as outcomes.
  2. When the data are grouped by Event Category, and if the total number of Events Reported exceeds the total number of unique event reports, then the percentages shown will exceed 100%. The percentages are based on the total number of unique events.
  3. The Hospitalized category includes every report classified as prolonged hospitalization. So, if you wish to see which events resulted in hospitalization, then select only the Hospitalized value for Event Category.
  4. When the data are exported, separate columns show both the label and the code for each value. These values are:
    Code    Label
    DTH Death
    LT Life Threatening
    DBL Permanent Disability
    H Hospitalized
    HP Hospitalized, Prolonged
    ER Emergency Room
    NSER Not Serious


Recovered

Select data from all events, or any combination of those reports that indicate whether the patient has recovered, not recovered, recovery is unknown, or the recovery information is missing from the report.

How?   See How do I select items from the list box? to select specific options in the list.
Notes:  
  • This field is box 9 on the VAERS Report Form . The box is labeled: "Patient Recovered." The specific instructions state, "Check "YES" if the patient's health condition is the same as it was prior to the vaccine, "NO" if the patient has not returned to the pre-vaccination state of health, or "UNKNOWN" if the patient's condition is not known."
  • When the data are exported, separate columns show both the label and the code for each value. These values are:
    Code    Label
    N No
    Y Yes
    U Unknown
    M Missing


Onset Interval

Select the number of days after vaccination before the onset of the adverse event.

How?   See "How do I select items from the list box?" for help using the list boxes.
Notes:   When the data are exported, separate columns show both the label and the code for each value. These values are:
Code    Label
0 0 days
1 1 day
2 2 days
3 3 days
4 4 days
5 5 days
6 6 days
7 7 days
8 8 days
9 9 days
10-14 10-14 days
15-30 15-30 days
31-60 31-60 days
61-120 61-120 days
121+ Over 120 days
U Unknown


Serious

Select data from all events, or those events that are classified as serious, or only non-serious events.

How?   See How do I select items from the list box? to select specific options in the list.
Notes:  
  1. Events are classified as serious when any of the following outcomes are associated with the event:   Death, Permanent Disability, Life Threatening reaction or Hospitalization.
  2. Send a request for data grouped by Serious and by Event Category to see the outcomes for this set of events.
  3. When the data are exported, separate columns show both the label and the code for each value. These values are:
    Code    Label
    SER Serious
    NSER Not Serious


Administered By

Select data from all events, or limit data to those events where the vaccination was administered by a public, private, other, military, or unknown agency.

How?   See How do I select items from the list box? to select specific options in the list.
Notes:  

When the data are exported, separate columns show both the label and the code for each value.


Purchased By

Select data from all events, or limit data to those events where the vaccine was purchased by a public, private, other, military, or unknown agency.

How?   See How do I select items from the list box? to select specific options in the list.
Notes:  
  • This field is box 16 on the VAERS Report Form . The box is labeled: "Vaccine purchased with: []Private funds []Public funds [] Military funds [] Other/Unknown." The specific instructions state, "This section refers to how the person who gave the vaccine purchased it, not to the patient's insurance."
  • When the data are exported, separate columns show both the label and the code for each value.


Grantee

Select data from all events, or limit data to those events where participation as a grant recipient was indicated.

How?   See How do I select items from the list box? to select specific options in the list.
Notes:  
  • Grantees include Chicago, Houston, New York City, Philadelphia and San Antonio.
  • When the data are exported, separate columns show both the label and the code for each value.

VAERS ID

Request data for specific event identification numbers.

How?  
  • Type full or partial VAERS IDs, one per line, into the VAERS ID box, to request data limited to matching events.
  • Send a request grouped by VAERS ID in order to see the unique event identification numbers.
  • Leave the box blank for all events.
Notes:  
  • Each event has a unique identification number, called the VAERS ID. Additional reports for an event correspond to the same VAERS ID as the primary report. The VAERS ID assigned to a particular report may change in data updates, when investigation determines that the report is related to a previously reported event. The first report ends in "-1" and subsequent reports are indicated in the order received, ending in "-2" for the second report, etc. When a report is later determined to refer to a previously reported event, then the VAERS ID is re-assigned, and the previous initial VAERS ID is shown in parenthesis. For example:
    Primary report ID:   012345-1
    Second report for the same event:   012345-2
    Later report recoded to this same event:    012345-3 (678910)
  • Beginning with the January 2011 data release, non-primary reports are no longer included in the data collection on CDC WONDER, in order to make these data comparable with the public downloadable data files available at the VAERS web site:  http://vaers.hhs.gov.


Previous VAERS ID

Request data for events that match the specified previous event identification numbers.

How?  
  • Type full or partial VAERS IDs, one per line, into the Previous VAERS ID box, to request data limited to matching events.
  • Send a request grouped by Previous VAERS ID in order to see the previous unique event identification numbers.
  • Leave the box blank for all events.
Notes:  
  • Each event has a unique identification number, called the VAERS ID. Additional reports for an event correspond to the same VAERS ID as the primary report. The VAERS ID assigned to a particular report may change in data updates, when investigation determines that the report is related to a previously reported event. The first report ends in "-1" and subsequent reports are indicated in the order received, ending in "-2" for the second report, etc. When a report is later determined to refer to a previously reported event, then the VAERS ID is re-assigned, and the previous initial VAERS ID is shown in parenthesis. For example:
    Primary report ID:   012345-1 (678910)
  • Most events do not have a previous VAERS ID.


Manufacturer/Immunization Project Number

Request data for events that match the specified Manufacturer/Immunization Project Number(s).

How?  
  • Type full or partial identifiers, one per line, into the box, to request data limited to events with matching Manufacturer/Immunization Project Numbers.
  • Leave the box blank for all events.
  • Type "NONE" to limit data to those events without a Manufacturer/Immunization Project Number.
Notes:  
  • This field is also known as "splttype."
  • Some specific Manufacturer/Immunization Project Numbers are associated with more than one event, more than one vaccine, or with more than one manufacturer.
  • Send a request grouped by Manufacturer/Immunization Project Number in order to see the identifiers. There are over 150,000 distinct identifiers, so you should also limit your query in some respect, such as selecting only a specific place or time period.
  • Some events have specified "unk" in this field to indicate an unknown value. These events are shown as reported and not recoded to show "NONE" as the value.
  • Many events do not indicate a Manufacturer/Immunization Project Number.


Step 6. Search text fields:
Limit your output by searching for words or phrases in any of these text fields:
  1. Adverse Event Description
  2. Lab Data
  3. Current Illness
  4. Adverse Events After Prior Vaccinations
  5. Medications At Time Of Vaccination
  6. History
Hints for searches:
  • Enter one or more words per line to find events with all words found in line. For example, if you type egg allergy, then your results show only records where both the egg and allergy were mentioned in the field.
  • Entries on more than one line will find events with any word or entire phrase found on each line. for example, if allergy is typed on the first line and sensitivity is typed on the second line, then your results show records that mention allergy OR sensitivity.
  • The default search is non-exact and finds events with other forms of the search term such as plurals. For example, if you type pregnancy, the search also looks for pregnancies. Or you can type geese and find mentions of goose.
  • Exact word searches can be performed by enclosing entire entry on single line in double quotes. For example, type "fetal loss" to look for that exact phrase only.
  • Use an asterisk (*) suffix after a word fragment to find events with this exact fragment at the beginning of the word. For example, type miscar* to find mentions of miscarry, miscarried, miscarriage, and miscarriages.
Other hints
  • To see the text fields that match your search criteria, be sure to go up to section 1 on the Request tab, group results by VAERS ID and also check the box to request the desired optional measure.
  • To see find the matches to your search terms in the results, after the Results tab displays the optional measures you have searched, then use your web browser's Search function to highlight the desired text. For example, open the web browsers "Edit" menu, then click the "Find on This Page" option in the menu. An entry field labeled "Find:" appears above your web page. Type the word you wish to see highlighted into this box.
Notes:
  • See VAERS Report Form for the instructions provided for completing the form. This information is also included in the description of each text field described below.
  • The contents of these fields are from the initial VAERS reports, and the text appears as submitted, except that any personal identifying information, such as names or addresses, have been removed.

Adverse Event Description
This field is box 7 on the VAERS Report Form . The box is labeled: "Describe adverse events(s) (symptoms, signs, time course) and treatment, if any." The specific instructions state, "Item 7: Describe the suspected adverse event. Such things as temperature, local and general signs and symptoms, time course, duration of symptoms, diagnosis, treatment and recovery should be noted."

Current Illness (at time of vaccination)
This field is box 18 on the VAERS Report Form . The box is labeled: "Illness at time of vaccination (specify)." The specific instructions state, "List any short term illnesses the patient had on the date the vaccine(s) was given (i.e., cold, flu, ear infection)."

Lab Data
This field is box 12 on the VAERS Report Form . The box is labeled: "Relevant diagnostic tests/laboratory data." The specific instructions state, "Include 'negative' or 'normal' results of any relevant tests performed as well as abnormal findings."

Adverse Events After Prior Vaccinations
This field is box 21 on the VAERS Report Form . The box is labeled: "Adverse event following prior vaccination (check all applicable, specify)."
  Adverse Event Onset Age Type Vaccine Dose no. in series
In patient



In brother
or sister




The specific instructions state, "List any suspected adverse events the patient, or the patient's brothers or sisters, may have had to previous vaccinations. If more than one brother or sister, or if the patient has reacted to more than one prior vaccine, use additional pages to explain completely. For the onset age of a patient, provide the age in months if less than two years old."

Medications At Time Of Vaccination
This field is box 17 on the VAERS Report Form . The box is labeled: "Other medications." The specific instructions state, "List any prescription or non-prescription medications the patient was taking when the vaccine(s) was given."

History
This field is box 19 on the VAERS Report Form . The box is labeled: "Pre-existing physician-diagnosed allergies, birth defects, medical conditions (specify)." The specific instructions state, "List any pre-existing physician-diagnosed allergies, birth defects, medical conditions (including developmental and/or neurologic disorders) for the patient."

About Selecting Dates
Select specific years or year/month dates to limit your request to the selected time periods. Choose between these two controls:
  1. The Date Range control is selected at first by default, with the full time period of available data shown in the range controls. Use this control to select a continuous span of time, such as May 25, 2010 - September 25, 2010.
  2. The Aggregate Date Finder lets you select specific, discrete year/month dates, such as January, 2003. Any number of distinct, separate dates may be selected.
How?
  • Click a round button to switch between Date Range, Individual Date Fields or Aggregate Dates.
  • Hints for the Date Range fields:
    • Click the down-arrow to the right of each field to open the drop-down list, then click on your selection in the list.
    • Click the blue counter-clockwise swoop image to the right of the date range fields to reset the entries to the default values (all).
  • Hints for the Individual Date Fields:
    • To select more than one value in the list, press down the Ctrl key on your keyboard while you click your left Mouse button.
    • To select a range of contiguous values, press down the Shift key on your keyboard while you click and drag your left Mouse button.
  • Hints for the Aggregate Date Finder:
    • See "How do I use a Finder?" for more information on using the Aggregate Date Finder.
    • See Finder Tool help for more hints.
    • The default for the Aggregate Date Finder is all values (2003/01/01 - 2011/12/31).
    • The Advanced mode let you easily pick several items from different parts of the list. Items are not selected until you click the "Move" button in Advanced mode. You may also enter values by hand, one code per line, in the Advanced mode. The code format is YYYY/MM/DD. For example, 2003/09 is September 2003.
    • The "plus" symbol, "+" indicates that you can open the item, to see more items below it.
    • The results to a search are shown in blue, and indicated by ">".
Notes:  
  1. The Finder combines all of the vaccination, onset and death dates from 1900 to 1979 in a single group labeled "Before 1980" because there are so few reports for this time period. Report dates have a "Before 1990" category because the VAERS program began in 1990. However, if the data are grouped by Month Vaccinated, then you can see the specific dates.
  2. The universe of possible vaccination, onset and report dates may change with each data update, to include new dates that were not previously reported. To see all possible values for vaccination dates at a given point in time, group the data request by Month Vaccinated.
  3. When the data are exported, separate columns show both the label and the code for each value.

Dates

Select a range of continuous time. The default is the full time-period found in the data, 2003 - 2011.
How?  
  • Click a round button to indicate Date Range Fields.
  • Click the down-arrow to the right of each field to open the drop-down list, then click on your selection in the list.
  • Click the blue counter-clockwise swoop image to the right of the range fields to reset the entries to the default values (all).

Step 7. Date Report was Completed

Date Report Completed

Select specific years or year/month dates to limit your request to the selected time periods for when the report was completed. See About Selecting Dates for more information using the controls.


Step 8. Select date report was received:

Date Report Received

Select specific years or year/month dates to limit your request to the selected time periods for when the report was received. See About Selecting Dates for more information using the controls.


Step 9. Select date vaccinated:

Date Vaccinated

Select specific years or year/month dates to limit your request to the selected time periods for when the vaccination was given. See About Selecting Dates for more information using the controls.


Step 10. Select date of onset of adverse health event:

Date of Onset

Select specific years or year/month dates to limit your request to the selected time periods for when the onset of the adverse health event occurred. See About Selecting Dates for more information using the controls.


Step 11. Select date of death:

Date Died

Select specific years or year/month dates to limit your request to the selected time periods for when the death occurred. See About Selecting Dates for more information using the controls.



Step 12. Other options:
Export Results:    If checked, then query results are exported to a local file. More information on how to import this file into other applications can be found here.
Show Totals:    If checked totals and sub-totals will appear in the results table.
Show Zero Values:    If checked rows containing zero values will appear in the results table. If unchecked, zero value rows are not displayed.
Precision:    Select the precision for the percentage calculations. When the measure calculated for a small numerator (number of items mentioned in reports) is zero, you may increase the precision to reveal the value by showing more numbers to the right of the decimal point.
Data Access Timeout:    This value specifies the maximum time to wait for the data access for a query to complete. If the data access takes too long to complete, a message will be displayed and you can increase the timeout or simplify your request. If you can't complete a request using the maximum timeout, contact user support and we will try to run a custom data request for you.

Data Source Information

The Vaccine Adverse Event Reporting System is a cooperative program for vaccine safety of the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA). VAERS is a post-marketing safety surveillance program, collecting information about adverse events (possible side effects) that occur after the administration of US licensed vaccines. This online database provides a nationwide mechanism by which these reports may be analyzed and made available to the public. The data are updated monthly and include reports received through the last Friday of the previous month.

To learn more about the methods and source of these data please refer to:


Additional Information

Suggested Data Source Citation:    United States Department of Health and Human Services, Department of Health and Human Services (DHHS), Public Health Service (PHS), Food and Drug Administration (FDA) / Centers for Disease Control (CDC), Vaccine Adverse Event Reporting System (VAERS) 1990 - last month, CDC WONDER On-line Database.
Contact:    Please call VAERS toll-free 1-800-822-7967 or e-mail info@vaers.org.
Data Limitations:    Review the limitations and interpret VAERS data with caution:
  • The data are unverified reports of health events, both minor and serious, that occur after vaccination. While some events reported to VAERS are truly caused by vaccines, others may be related to an underlying disease or condition, to drugs being taken concurrently, or may occur by chance shortly after a vaccine was administered.
  • VAERS data are from a passive surveillance system. Such data are subject to limitations of under-reporting, reporting bias, and lack of incidence rates in unvaccinated comparison groups.
  • Reports show the simultaneous administration of multiple vaccine antigens (making it difficult to know to which of the vaccines, if any, the event might be attributed).
  • VAERS occasionally receives case reports from US manufacturers that were reported to their foreign subsidiaries. Under FDA regulations, if a manufacturer is notified of a foreign case report that describes an event that is both serious and unexpected (in other words, it does not appear in the product labeling), they are required to submit it to VAERS. These case reports are of variable data quality and completeness, due to the many differences in country reporting practices.
  • In some media reports and on some web sites on the Internet, VAERS reports are presented as verified cases of vaccine deaths and injuries. Statements such as these misrepresent the nature of the VAERS surveillance system.
  • Establishing causal relationships between vaccines and adverse events requires additional scientific investigation. The CDC and FDA take into account the complex factors mentioned above, and others, when monitoring vaccine safety and analyzing VAERS reports.
  • VAERS staff at CDC and the Food and Drug Administration (FDA) follow up on all serious adverse event reports to obtain additional medical, laboratory, and/or autopsy records to help understand the circumstances. However, VAERS public data do not generally change based on the information obtained during the follow-up process.

    There are limitations to VAERS data. A report to VAERS does not mean that the vaccine caused the adverse event, only that the adverse event occurred sometime after vaccination. Read more about interpreting VAERS data at Additional Information: Data Limitations.

About Multiple Mentions:    Some items may have more than 1 occurrence in any single event report, such as Symptoms, Vaccine Products, Manufacturers and Event Category. If data are grouped by any of these items, then the number in the Events Reported column may exceed the total number of unique events. If percentages are shown, then the associated percentage of total unique event reports will exceed 100% in such cases. For example, the number of Symptoms mentioned is likely to exceed the number of events reported, because many reports include more than 1 Symptom. When more than 1 Symptom occurs in a single report, then the percentage of Symptoms to unique events is more than 100%.

Prior to November 1, 2009, measures showed the label "suppressed" when the value was more than the number of unique events included in the request criteria. This can happen when "non-primary" reports are included, (additional reports associated with a single event; no longer available after January 2011) or when the data are grouped by a variable that may have more than one value in any single report.

About Reporting Delays and Data Completeness:    VAERS reports are included through the last Friday of the previous month, based on the date received by the VAERS system. The VAERS data in WONDER are updated monthly, yet the VAERS system receives continuous updates including revisions and new reports for preceding time periods. The data included in WONDER represent a "snap shot" of the VAERS records for reports received through the preceding month at a given point in time, typically the previous Friday. For example, a report form is filled out on February 27th, for an event that occurred in January. The VAERS system receives the report on March 3rd. Due to processing time for data entry and verification, the report is entered into the electronic records on March 6th. Corrections or follow-up reports are entered into the record on March 16th. The initial report is captured in the WONDER system's "snap shot" on the Friday following March 6th, and is released to the public by the next Monday. However, the corrections are not captured in the WONDER system until the Monday release following the date that the corrections entered the electronics records system. The data are more complete as time passes.
About the VAERS Event Details Report:    How to see all data for a single report?
The report feature allows you to search for details on any specific VAERS report by the VAERS ID number. There are 3 ways to get a report showing all of the data for a single event report.
  1. Select the "VAERS Report Details" button on the About page, which moves you to the "Report" tab and shows the "Event Details Report" page.
    - or -
  2. Click the "Report" tab to move to the "Event Details Report" page.
    - or -
  3. Send a data request from the "Request Form" tab and group results by VAERS ID. Each VAERS ID in the Results is a link to the Event Details report for that event.
Hints:
  • From the "Report" tab and the "Event Details Report" page:
    1. Type a VAERS ID into the "VAERS ID" box.
    2. Then click the "Event Details" button to get an event details report for the matching VAERS ID.
  • After a report is displayed:
    • Look below the report to find the "Event Details Report" form and request another report.
      - or -
    • If you have a Results table grouped by VAERS ID, then click the "Results" tab to return to the list of VAERS IDs after you have displayed a specific report.
  • A VAERS ID consists of six numbers followed by -1, such as 123456-1. Since all primary VAERS IDs end with -1, you may omit the '-1' from IDs entered here. for example, type 123456. Please note that some VAERS IDs start with 0, such as 012345-1. Only primary VAERS reports are included in CDC WONDER.
  • Each report shows the values for all of the fields available in CDC WONDER. See the list of variables for more information on any specific field.




This page last reviewed: Monday, January 25, 2016
This information is provided as technical reference material. Please contact us at cwus@cdc.gov to request a simple text version of this document.
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