The FDA’s new strategy to adapt drugs, tests and vaccines to variants is the cornerstone of the government’s battle plan, drawn up in part by years of experience in combating the rapidly changing flu virus. The work consumed FDA employees, according to an industry executive. Meanwhile, officials at the National Institutes of Health – the broad scientific campus where Anthony Fauci leads infectious disease research – are working with at least two vaccine manufacturers, including Moderna, to start human trials next month of vaccines with variant targets.
FDA team chief Julie Tierney said on Thursday that the agency anticipated the need to assess the effectiveness of vaccines against emerging variants. “This is an issue that we are definitely thinking about and working with individual sponsors of,” Tierney told the Food and Drug Law Institute. “And we are looking for a more public process to disseminate our thinking in the very near future.”
At a news conference on Thursday, the agency’s acting director, Janet Woodcock, emphasized the value of giving uniform written advice to manufacturers of drugs, vaccines and tests. “It will also provide the scientific community and the public [a chance to] comment on what we’re thinking, and maybe we can refine our thinking, “she said.
Public health experts say there are important lessons for the FDA in the long-standing global approach to influenza. Vaccines made annually to fight the flu depend on a basic vaccine that is then changed to combat the specific variants that appear each season. Taking advantage of flu vaccine practices would mean that manufacturers could skip tests for months involving thousands of people and instead prove safety and effectiveness in smaller studies that track a few hundred volunteers for weeks.
Peter Marks, the FDA’s top vaccine official, signaled on Friday that the agency is leaning towards this approach. The agency is “working with industry partners to put together a manual of what it will look like if we need to move to a different sequence,” said the director of the Center for Biological Research and Evaluation during an American Medical Association event. I would intend to be very agile with this, as agile as possible when you are dealing with a large infrastructure, such as vaccine manufacturing, so we cover these variants as quickly as possible. “
Quick responses from these tests will be critical as the country faces the spread of coronavirus strains. Each has its own peculiarities, but what emerged in South Africa, B.1.315, alarms regulators after the main vaccines are less effective, but still protective, against him in tests. The variant has already been found in at least two U.S. states. The researchers say the other strains, which appear to be more transmissible than the original virus, may also acquire resistance to the B.1.315 vaccine.
Adapting the flu strategy is an approach advocated by scientists. It is not practical to carry out complete end-stage tests for booster vaccines or revised Covid-19 vaccines, said Paul Offit, a vaccine expert at the University of Pennsylvania who sits on the FDA’s vaccine advisory board.
“The flu model is the only thing that makes sense,” said Offit, and not just because the limited tests could be carried out quickly. “Thirty million people have already had vaccines, 20% of people are already immune. You would have trouble doing an effectiveness test, ”signing up thousands for a strain of the virus.
Instead, health officials would use what is known as a transition study, which involves applying specific research data related to broader assumptions about the effectiveness or safety of a vaccine. In the case of coronavirus vaccines, scientists could measure the levels of antibodies in someone who has recovered from a strain like B.1.351 and use those levels to assess the potency of potential booster doses, suggested former FDA commissioner Scott Gottlieb in a recent Wall Street Journal op-ed.
The FDA also appears to endorse the change. “We do not believe there is a need to start from scratch with any of these products – we recognize that we are in a pandemic and we need to equip health professionals with the most appropriate tools to fight this pandemic on the front lines. We do not want to create obstacles to take these tools to the front line, “said Woodcock in the statement.
But the challenges hardly end with ensuring that modified vaccines are safe and effective. Manufacturers that are already struggling to meet the worldwide demand for doses of existing vaccines also need to increase production and distribution of new versions.
These complicated distribution plans may be on the horizon, but for now health officials are simply planning on the possibility of quickly needed reinforcements. “We haven’t crossed the line yet,” said Offit. “The line is crossed when people who have been fully vaccinated with two doses of one of these [authorized] vaccines are, however, hospitalized with one of these variant strains. “
This did not happened. Although manufacturers, including Moderna and Johnson & Johnson, report that their vaccines appear less effective against the strain first found in South Africa, they still elicit a strong enough response to protect most people from serious illnesses.
Moderna, which worked closely with the NIH to develop its original vaccine, aims to place a booster injection in human trials next month. NIH is also working with Gritstone Oncology, a biotechnology company with experimental technology that could incorporate protection against multiple strains of coronavirus into a vaccine.
Until the booster or new vaccines are ready, tracking the movements of the variants through accurate genetic sequencing of patient samples and diagnostic tests will be vital to prevent an outbreak of infections from the new strains.
FDA’s director of diagnostics, Tim Stenzel, asked diagnostic manufacturers to consider how the variants may affect the performance of their Covid-19 tests and said the agency would be happy to speak with developers looking to make updates. The regulator said earlier that the FDA would work with the CDC to assess how well antigen tests that are already on the market detect emerging variants, but it is unclear how quickly the effort is progressing.