In a Friday letter to Bavaria Nordic CEO Paul Chaplin, two senior FDA officials echoed concerns raised by Chaplin earlier this week. The agency recently determined that the benefits of expanding its limited supply of two-dose Jynneos vaccine by giving individuals smaller doses outweigh the known possible risks, they wrote.
The FDA letter, obtained by CNN Saturday, was signed by FDA Commissioner Dr. Robert Califf and Dr. Peter Marks, director of the FDA’s Center for Biologics and Evaluation Research.
The letter cites a 2015 clinical study co-authored by Chaplin in which “individuals vaccinated intradermally received a lower volume (one-fifth) than those vaccinated subcutaneously.”
“The results of this study demonstrate that intradermal administration produces a very similar immune response to subcutaneous (SC) administration,” the letter said. While the intradermal injection method “did result in redness, stiffness, itching and swelling at the injection site, the pain was reduced,” the letter continued, “these side effects were manageable.”
The FDA also detailed other options the agency has considered. But the letter said the use of alternative vaccines to prevent monkeypox “is currently determined to be impractical or undesirable.” Specifically, the ACAM2000 vaccine, which is FDA-approved to prevent smallpox, “may not be suitable for immunocompromised populations right now,” the letter said.
The FDA also looked at options for delaying the second dose of the vaccine by three to six months, rather than giving the second dose 28 days after the first.
But the agency ultimately determined that there was no data to suggest this approach would provide adequate protection, and that delaying the second dose of the vaccine could also give people “a false assurance that they will not get monkeypox at the actual level of protection they will get.” Feel reassured. The unknown is probably not enough,” the letter said.
The FDA’s Dr. Marks said Thursday that an estimated 1.6 million to 1.7 million people in the U.S. are currently eligible for two doses of the Jynneos vaccine. About 634,213 vials had been sent to jurisdictions as of Friday, according to the U.S. Department of Health and Human Services.
The low-dose intradermal strategy immediately caught the attention of some public health experts, including the limited number of studies surrounding this new approach.
“This approach raises red flags after red flags and appears to be working in the absence of data on efficacy, safety, or alternative dosing strategies,” David Harvey, executive director of the National Coalition of STD Directors, said in a statement this week. Move forward in a hurry.”
Chaplin, chief executive of Bavarian Nordic, also raised concerns. CNN reported that Chaplin wrote Tuesday in a letter to California and HHS Secretary Xavier Becerra that he was concerned about the “very limited safety data available” for the newly announced vaccination strategy and that clinical A relatively high percentage of people in the study — 20 percent — did not get a second shot.
“While we have some reservations, we are working hard to find support [emergency use authorization] By collecting more data and adapting the response to assist state officials in the rollout,” Chaplin wrote. “We are also investing in expanding the manufacturing capacity of BN and external facilities, with more announcements likely to follow soon.