Vaccine Safety Signal for Seniors Preliminary Identified

Transparency and vaccine safety are top priorities for the U.S. Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA), stated these organizations today.

Often these safety systems detect signals that could be due to factors other than the vaccine itself, affirmed these agencies on January 13, 2023.

All signals require further investigation and confirmation from formal epidemiologic studies.

When one system detects a signal, the other safety monitoring systems are checked to validate whether the signal represents an actual concern with the vaccine or if it can be determined to be of no clinical relevance.

Following the availability and use of the updated (bivalent) COVID-19 vaccines, CDC’s Vaccine Safety Datalink (VSD), a near real-time surveillance system, met the statistical criteria to prompt additional investigation into whether there was a safety concern for ischemic stroke in people ages 65 and older who received the Pfizer-BioNTech COVID-19 Vaccine, Bivalent.

Rapid-response investigation of the signal in the VSD raised a question of whether people 65 and older who have received the Pfizer-BioNTech COVID-19 Vaccine, Bivalent, were more likely to have an ischemic stroke in the 21 days following vaccination compared with days 22-44 following vaccination.

The Moderna COVID-19 Vaccine, Bivalent, has not identified this preliminary signal.

There also may be other confounding factors contributing to the signal identified in the VSD that merit further investigation.

Furthermore, it is essential to note that, to date, no other safety systems have shown a similar signal, and multiple subsequent analyses have not validated this signal:

• A large study of updated (bivalent) vaccines (from Pfizer-BioNTech and Moderna) using the Centers for Medicare and Medicaid Services database revealed no increased risk of ischemic stroke
• And preliminary study using the Veterans Affairs database did not indicate an increased risk of ischemic stroke following an updated (bivalent) vaccine.
• The Vaccine Adverse Event Reporting System managed by CDC and FDA has not seen an increase in reporting of ischemic strokes following the updated (bivalent) vaccine.
• Pfizer-BioNTech’s global safety database has not indicated a signal for ischemic stroke with the updated (bivalent) vaccine.
• Other countries have not observed an increased risk for ischemic stroke with updated (bivalent) vaccines.

Although the totality of the data currently suggests that it is very unlikely that the signal in VSD represents an actual clinical risk, we believe it is essential to share this information with the public, as we have in the past, when one of our safety monitoring systems detects a signal.

The CDC and FDA will continue to evaluate additional data from these and other vaccine safety systems.

These data and additional analyses will be discussed at the upcoming January 26, 2023, meeting of the FDA’s Vaccines and Related Biological Products Advisory Committee.

As of January 14, 2023, there is no change in vaccination practice recommended.

CDC recommends that everyone ages six months and older stay up-to-date with COVID-19 vaccination, including individuals currently eligible to receive an updated (bivalent) vaccine.

Data have shown an updated COVID-19 vaccine reduces the risk of hospitalization from COVID-19 by nearly 3-fold compared to those previously vaccinated but have not yet received the updated vaccine.

Moreover, data have shown that the updated COVID-19 vaccine also reduces the risk of death from COVID-19 by nearly 19-fold compared to those who are unvaccinated.

Overall safety data for the bivalent COVID-19 vaccines are available at this link.

Once again, no change is recommended in COVID-19 vaccination practice, which can be found here, says the CDC and FDA.

The unedited, full announcement is posted at this FDA link.