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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:   Please note that VAERS staff follow-up on all serious and other selected adverse event reports to obtain additional medical, laboratory, and/or autopsy records to help understand the health concern raised. However, in general, coding terms in VAERS do not change based on the information received during the follow-up process. VAERS data on WONDER should be used with caution as numbers and conditions DO NOT reflect data collected during follow-up. Note that information included in the VAERS data does not mean that the vaccine caused the adverse event. Review cautions in the interpretation of this data.

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 incidence counts of event reports, show the percentage of unique events and display each event's Adverse Event Description. 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:

  1. Symptoms - classified with Medical Dictionary for Regulatory Activities (MedRA)
  2. Vaccine Products - vaccine type and name
  3. Manufacturers - makers of vaccine products
  4. Onset Interval - number of days after vaccine when symptoms occurred.
  5. Serious - indicates whether event was classed as serious.
  6. Recovered - indicates if the patient recovered fully.
  7. Event Category - describes the outcome of the event.
  8. VAERS ID - unique identification number for this event.
  9. State / Territory
  10. Year and Month Vaccinated
  11. Year and Month Reported
  12. Age
  13. Gender

Please refer to the following topics:

VAERS Data Request
Data Source Information
Additional Information

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 these variables:

Event characteristics:

  1. Symptoms - classified with Medical Dictionary for Regulatory Activities (MedRA)
  2. Vaccine Products - vaccine type and name
  3. Manufacturers - makers of vaccine products
  4. Onset Interval - number of days after vaccine when symptoms occurred.
  5. Serious - indicates whether event was classed as serious.
  6. Recovered - indicates if the patient recovered fully.
  7. Event Category - describes the outcome of the event.
  8. VAERS ID - unique identification number for this event.

Location, time and demographics:

  1. State / Territory
  2. Year and Month Vaccinated
  3. Year and Month Reported
  4. Age
  5. Gender
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 and label results;
Step 2, Select event characteristics
Step 3, Select location, time and demographics
Step 4, 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. About charts:
    You cannot make charts when your data has more than two By-Variables.
  2. 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.
  3. About Adverse Event Descriptions:
    To show the narrative text submitted with each event report, you must group by VAERS ID. Then click the checkbox for Adverse Event Descriptions.
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 then 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 then 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.

Adverse Event Descriptions

Check the box in Section 1 with your Mouse of Spacebar key to display the narrative text submitted with each event report.

Hints:  

  • You must group by VAERS ID when selecting Adverse Event Descriptions.
  • The limit for the number of rows returned in any single results set is lower when the results include the Adverse Event Descriptions, due to the size of this field. The field may contain up to 2080 characters. 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.
  • 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.
  • 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 products:

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:
  1. Each event report may be assigned multiple vaccine products, because the patient may have received more than one vaccination before the adverse event occurred.
  2. 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.
  3. 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.
  4. When the data are exported, separate columns show both the label and the code for each value.
Step 4. Select event characteristics:
  • Manufacturers - makers of vaccine products
  • Onset Interval - number of days after vaccine when symptoms occurred.
  • Serious - indicates whether event was classed as serious.
  • Recovered - indicates if the patient recovered fully.
  • Event Category - describes the outcome of the event.
  • VAERS ID - unique identification number for this event.
    • 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.

    Manufacturers

    Select vaccine product manufacturers for the query.

    How?   See "How do I select items from the list box?" for help using the list boxes.
    Notes:
    1. 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.
    2. 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.
    3. When the data are exported, separate columns show both the label and the code for each value.

    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

    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:   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

    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

    VAERS ID

    Request data for specific or partial 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.
    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 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.

    Step 5. 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 6. Select date vaccinated:

    Date Vaccinated

    Select specific years or year/month dates to limit your request to the selected dates.

    How?
    • The first level shown are the years. Click the Open button to see the list of months in each year. The default value is the full range of years and months in the data collection.
    • See "How do I use a Finder?" for help.
    • If you prefer, You can also enter date values by hand:
      1. Click the link for Advanced mode. (Advanced mode is only available when JavaScript is enabled.)
      2. Use yyyy (1994) for years, yyyy/mm (1992/01) for months. Enter one date per line.
    • See Finder Tool help for more hints.
    Notes:  
    1. The Finder combines all of the vaccination dates from 1900 to 1979 in a single group labeled "Before 1980" because there are so few reports for this time period. However, if the data are grouped by Month Vaccinated, then you can see the specific dates.
    2. The universe of possible vaccination 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.
    Step 7. Select date reported:

    Date Reported

    Select specific years or year/month dates to limit your request to the selected dates.

    How?
    • The first level shown are the years. Click the Open button to see the list of months in each year. The default value is the full range of years and months in the data collection.
    • See "How do I use a Finder?" for help.
    • If you prefer, You can also enter date values by hand:
      1. Click the link for Advanced mode. (Advanced mode is only available when JavaScript is enabled.)
      2. Use yyyy (1994) for years, yyyy/mm (1992/01) for months. Enter one date per line.
    • See Finder Tool help for more hints.
    Notes:  
    1. The universe of possible report dates may change with each data update, to include new dates that were not previously reported. To see all possible values at a given point in time, group the data request by Month Reported.
    2. When the data are exported, separate columns show both the label and the code for each value.

    Step 8. 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 precentage 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

    Data Sources 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 Citations 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
    • 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.
    • Please note that VAERS staff follow-up on all serious and other selected adverse event reports to obtain additional medical, laboratory, and/or autopsy records to help understand the health concern raised. However, in general, coding terms in VAERS do not change based on the information received during the follow-up process. VAERS data on WONDER should be used with caution as numbers and conditions DO NOT reflect data collected during follow-up. Note that information included in the VAERS data does not mean that the vaccine caused the adverse event. Review cautions in the interpretation of this data.
    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 then 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 redcords system. The data are more complete as time passes.



    This page last reviewed: Thursday, November 29, 2012
    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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