New Postmarket Surveillance Tool for COVID-19 Vaccines Being Used

As U.S. vaccinations against COVID-19 gain momentum, health officials are using new tools to gather postmarket safety data, including a new early warning system called V-Safe.

Launched in December ahead of the nationwide rollout of the Pfizer/BioNTech vaccine, the smartphone-based tool allows the Centers for Disease Control and Prevention (CDC) to check in with patients after they receive an initial shot or booster — by sending texts that link to web-based surveys of their health status.

Data collected by the tool will likely prove essential for vaccine developers who are required to report to the FDA on postmarket monitoring of their products after they receive Emergency Use Authorizations from the FDA.

For the first week postvaccination, V-Safe sends daily survey links, then weekly check-ins for six weeks when “most of the common symptoms like pain at the injection site, headache and fever have gone away,” a CDC spokesperson explained. V-Safe will send subsequent follow-up surveys at three, six- and 12-months after injection. The system can also send alerts reminding the inoculated individuals to get their second shot, although it can’t be used to schedule appointments.

Unlike passive monitoring systems, V-Safe allows the CDC to actively gather health impact data in real time, including self-reported side effects. The current data reveal that those who have received a second shot report an increase in side effects. The symptoms, such as fever, chills, fatigue and joint pain “are generally a sign that the vaccine is working, that the immune system is doing its job,” the CDC spokesperson said.

“We’ve been able to get rich information on the reactogenicity of these vaccines,” Tom Shimabukuro, deputy director of CDC’s Immunization Safety Office, told FDAnews. Based on its early success, Shimabukuro predicts V-Safe system will become standard for vaccine monitoring. Two million people signed up for the program during the first five-and-a-half weeks of U.S. vaccine distribution.

But V-Safe isn’t the only early warning system in the CDC’s arsenal. The agency, in conjunction with the FDA, also relies heavily on the Vaccine Adverse Event Reporting System (VAERS), launched in 1990 that collects safety data from state and local health departments. These agencies are required by law to send the information, but patients may also use the system to report adverse events.

Once VAERS reports are received, they are uploaded into a large database which codes the reports as being serious or nonserious. One weakness of the program is its inability to determine what causes an adverse event. However, if a report is classified as serious, the CDC will follow up and collect medical records.

The CDC is aggressively tracking 15 potential serious adverse events it is aggressively tracking during the pandemic. They include acute myocardial infraction, anaphylaxis caused by allergic reaction and how vaccines affect pregnant women. Shimabukuro notes that “these lists are dynamic” and that pre-specified adverse events are subject to change as the CDC gathers more data on what to expect from inoculations.

“It is advisable to have multiple, complementary systems in place to rapidly both detect possible safety problems and to assess possible safety problems,” he said, adding that initial safety data or trends gleaned from V-Safe or VAERS can be evaluated further using the inter-governmental Vaccine Safety Datalink, a monitoring system that can better assess adverse event causality, or the CDC’s Clinical Immunization Safety Assessment, which conducts detailed case reviews of complex adverse events.

Other nations have already begun to report their findings from postmarket surveillance of vaccines. On Friday, the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) reported data on 22,820 adverse event reports from early December to late January that showed vaccine side effects were “mild and short-lasting, reflecting a normal immune response to vaccines.”

As of late last week, the UK had vaccinated more than 15 percent of its population with the AstraZeneca/Oxford University, Pfizer/BioNTech or Moderna vaccines.

“The data we have collected provide further reassurance that the COVID-19 vaccines are safe and continue to meet the rigorous regulatory standards required for all vaccines,” said MHRA Chief Executive June Raine. “We remain confident that the benefits of these vaccines outweigh any risks.” ― Jason Scott