Citing a “new evidenced based philosophy,” the FDA’s Center for Biologics Evaluation and Research (CBER) is preparing to take a hard line against the common practice of administering certain respiratory virus vaccines at the same time.
The leadership at CBER—which oversees vaccines and other biologic products like cell and gene therapies at the FDA—will now require randomized, controlled trials in people eligible for multiple vaccines before drugmakers can promote coadministration of the shots or “some sequence of the vaccines,” CBER Director Vinay Prasad, M.D., wrote in a memo posted on the FDA’s website.
“The trial could be performed with a hierarchical statistical design, testing first noninferiority and then superiority,” Prasad said in the communique, which was issued in relation to the FDA’s restricted approval of Pfizer’s updated COVID-19 shot last week.
“The primary endpoint would be clinical, for instance: symptomatic RSV, COVID-19, and influenza,” he continued. “Secondary endpoints would be severe disease, and adverse events.”
When reached for comment on the memo, a Department of Health and Human Services (HHS) spokesperson told Fierce Pharma that “the FDA will announce a new framework for this soon.”
Although the new requirement was laid out in communications on Pfizer’s coronavirus vaccine Comirnaty, it will likely affect any company manufacturing vaccines for COVID-19, influenza or respiratory syncytial virus.
Apparently reading the writing on the wall, Pfizer last month sent a letter to healthcare providers warning that certain lots of its 2025-26 COVID vaccine “contain unapproved prescribing information inside the cartons.”
That language related to “concomitant administration of Pfizer-BioNTech COVID-19 vaccine, bivalent with a respiratory syncytial virus (RSV) vaccine or with an RSV vaccine and an influenza vaccine in individuals 65 years of age and older,” according to the letter, which the FDA has posted on its Comirnaty information page.
Pfizer did not provide a statement in response to Prasad’s communications, though a company spokesperson directed Fierce toward its physician letter on the FDA’s website.
In the memo, CBER’s Prasad took issue with the fact that past company claims about concomitant vaccine administration were “made on the basis of small randomized studies showing non-inferior antibody titers.” But the CBER is “unsure” whether those titers correspond to clinical protection and holds concerns that “such small trials are inherently incapable of adequately documenting safety signals,” according to Prasad.
“The studies are simply too small to identify potential increases in adverse events, which Americans may wish to know,” he wrote.
The Biden administration supported vaccine coadministration as a means to increase immunization rates, though Prasad has frequently criticized the practice, The Washington Post reported this week.
Prior research has suggested that receiving certain vaccines during the same pharmacy or doctor visit is perfectly safe. The Post pointed to a Centers for Disease Control and Prevention (CDC) study from 2022, which found that while patients who got a flu and COVID vaccine at the same time were more likely to experience side effects like fatigue, headache and muscle pain than those who just received the COVID shot, the reactions were mostly mild and tended to fade quickly.
The CBER’s increased scrutiny of vaccine administration practices comes at a tumultuous time for immunization policy more broadly in the U.S.
At the highest levels, anti-vaccine viewpoints held by HHS Secretary Robert F. Kennedy Jr. and his allies have led to the apparent ousting and stonewalling of multiple prominent experts in the field, evident in RFK Jr. ’s purge of the CDC’s Advisory Committee on Immunization Practices, the stinging resignation of former CBER chief Peter Marks, M.D., Ph.D., and the news this week that prominent vaccine researcher Paul Offit, M.D., has been blocked from participating on a key FDA advisory panel.
Concerned by the situation at the CDC in particular—which just last week lost its Trump-appointed director over alleged beef with RFK Jr.’s vaccine viewpoints—California, Oregon and Washington on Wednesday announced plans to form a “health alliance” to coordinate unified public health recommendations and take vaccine guidance into their own hands.
Meanwhile, the ability of everyday Americans to access inoculations against COVID-19 may soon be diminished thanks to recent regulatory moves.
Last week, the FDA signed off on updated formulations of the mRNA COVID vaccines from Pfizer and Moderna. The green lights came with heavy restrictions, however, requiring that patients under the age of 65 have at least one underlying health condition to qualify for a shot. Both Pfizer’s Comirnaty and Moderna’s Spikevax retained broad approvals in adults ages 65 years and older.