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FDA asks Covid-19 vaccine developers for 2 months of safety data before considering emergency use authorization

Such a requirement implies that a Covid-19 vaccine may not be authorized before the presidential election on November 3

The US Food and Drug Administration (FDA) has issued tougher guidelines for coronavirus vaccine developers, asking them to follow study volunteers for at least two months to look for any possible safety issues before the agency would consider emergency use authorization (EUA). Such a requirement implies that a Covid-19 vaccine may not be authorized before the presidential election on November 3. 

The FDA notes that there would need to be an adequate plan for safety data collection among individuals vaccinated under EUA. The EUA request for a Covid-19 vaccine should include all safety data from phase 1 and 2 studies conducted with the vaccine, with a focus on serious adverse events, adverse events of special interest, and cases of severe coronavirus among study subjects, says the agency.

“Data from phase 3 studies should include a median follow-up duration of at least two months after completion of the full vaccination regimen to help provide adequate information to assess a vaccine’s benefit-risk profile, including adverse events, cases of severe Covid-19 disease among study subjects, and cases of Covid-19 occurring during the timeframe when adaptive (rather than innate) and memory immune responses to the vaccine would be responsible for a protective effect,” says the guidance. It adds, “We recognize that the phase 1 and 2 safety data likely will be of a longer duration than the available safety data from the phase 3 trial at the time of submission of an EUA request. The phase 1 and 2 data are intended to complement the available data from safety follow-up from ongoing phase 3 studies.”

President Donald Trump has repeatedly hinted that a vaccine would be ready by November 3. Reports had earlier emerged that the new guidance for the emergency use authorization of a Covid-19 vaccine by the FDA — including one that may ensure that no coronavirus vaccine is authorized before election day — is being blocked by the White House. Reacting to the latest FDA guidelines, the president tweeted: “New FDA rules make it more difficult for them to speed up vaccines for approval before election day. Just another political hit job!” He also tagged Dr FDA commissioner Stephen Hahn in the tweet.

There are currently no FDA-licensed vaccines to prevent Covid-19. Commercial vaccine manufacturers and other entities are developing coronavirus vaccine candidates using different technologies including RNA, DNA, protein, and viral vectored vaccines. 

In an interview with JAMA, Dr Peter Marks, director of the Center for Biologics Evaluation and Research, the FDA division that approves vaccines, said: “We’ve made it clear that we want to see a median of about two months of follow up for any of the vaccines that come in, and while it would be nice to have much more, we have to balance the safety we get upfront with the need to try to save lives with a vaccine that’s helping to prevent a virus that’s killing 1,000 or more people a day in the US.” 

Dr Marks further said, “Safety is what keeps me up at night. Because the way we’re going to get over Covid-19 is if we get a vaccine that has 70% or 80% efficacy and we can deploy that to 70 or 80% of the population, we actually have a chance of having herd immunity, and we can be back in restaurants and in banks, and doing what we normally do. It’s only going to happen if people have confidence enough to go get vaccinated and we do have a crisis in vaccine confidence now.”

According to Dr Marks, being open and clear about the circumstances under which the issuance of an emergency use authorization for a Covid-19 vaccine would be appropriate and is critical to building public confidence and ensuring the use of coronavirus vaccines once available. “The FDA’s new guidance on emergency use authorization of Covid-19 vaccines underscores that commitment by further outlining the process and recommended scientific data and information that would support an emergency use authorization decision. In addition to outlining our expectations for vaccine sponsors, we also hope the agency’s guidance on Covid-19 vaccines helps the public understand our science-based decision-making process that assures vaccine quality, safety, and efficacy for any vaccine that is authorized or approved.”

Meanwhile, the FDA also expects vaccine makers to document five cases of severe infection in people who received the placebo instead of the vaccine. “Sufficient cases of severe Covid-19 among study subjects to support low risk for vaccine-induced enhanced respiratory disease or ERD (a total of 5 or more severe Covid-19 cases in the placebo group would generally be sufficient to assess whether the severe Covid-19 case split between vaccine vs. placebo groups supports a favorable benefit-risk profile or conversely raises a concern about ERD,” it explains.

In general, FDA’s guidance documents, including the current guidance, do not establish legally enforceable responsibilities. Instead, guidances describe the agency’s “current thinking on a topic and should be viewed only as recommendations,” unless specific regulatory or statutory requirements are cited, the document specifies. The advisory, however, reiterates that any assessment regarding an EUA will be made on a case-by-case basis considering the target population, the characteristics of the product, the preclinical and human clinical study data on the product, and the totality of the available scientific evidence relevant to the product.

The FDA also plans to convene an open session of its Vaccines and Related Biological Products Advisory Committee (VRBPAC) before issuing any EUA for a coronavirus vaccine to discuss the EUA request and whether the available safety and effectiveness data support the authorization. The VRBPAC is currently scheduled to meet on October 22 to discuss the general development, authorization and /or licensure of Covid-19 vaccines.