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Information Center

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Understanding VAERS Release Dates

The U.S. Government makes periodic releases of VAERS data. Each release is dated according to the latest report placed in the system, so if the release is dated March 2, that means it has all cases that have been entered into VAERS as of March 2.

In general, the government releases data monthly, and the date of the release is the previous month. For example, when they post data on October 17 it has data up to September 14, and this release remains current until the November 17 release. Because of this, there are times when the data is two months old.

During COVID, the government did weekly releases of the data, and each week's data was only one week old. For example, the release made on January 22 included data up to January 15, and this release remained current until the January 29 release. During these times, the data was never more than two weeks old. updates the data as soon as the government releases it, usually within an hour of posting. If you look at the government's search engine, CDC Wonder, you will see the same date as MedAlerts. The two sites are in complete sync, because they are both fed from the government's data releases.

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