The Food and Drug Administration has laid the groundwork for drugmakers to be able to react quickly to emerging coronavirus variants and get modified products to the public without the need for extended clinical trials.
"We are using every tool in our toolbox to fight this pandemic, including pivoting as the virus adapts," Dr. Janet Woodcock, acting FDA commissioner, said in a statement Monday.
Evidence so far suggests that the two Covid-19 vaccines authorized in the U.S., from Moderna and Pfizer-BioNTech, appear to offer good protection against new variants.
But the fact that the virus continues to mutate means drugmakers will need to keep up, adapting quickly if necessary. The FDA guidance suggests companies may be able to pull back on lengthy clinical trials to prove safety and effectiveness each time a new variant emerges.
This is not unlike how the flu shot changes from year to year.
"For influenza, we are so accustomed to doing this," Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said on a call with reporters Monday. Because the flu shot is so well studied, human clinical studies are unnecessary each year. Manufacturers simply modify the shots based on the strains that are predicted to be in circulation.
Until experts have more data on Covid-19 vaccines, however, the FDA will continue to require drugmakers to study their vaccines' efficacy against emerging strains.
"We need to understand whether the new vaccine strain is able to cover both the new strain and the old strain," Marks said. Additional safety data, at least in the interim, will be necessary.
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"After we do that three or four times, we'll look at everything, and if everything seems consistent, then we might move more towards the influenza-like model," Marks said.
The FDA guidance also recommends developers of Covid-19 diagnostic tests and makers of monoclonal antibody treatments monitor how emerging variants might affect their effectiveness.