The Vaccines and the Variants

The FDA has just released an updated Guidance that outlines the Agency’s current scientific recommendations for modifications to authorized vaccines to meet the challenge of the new variants that are present – and increasing – in the United States. As Dr. Robert Edwards explained in his recent Alert entitled “Novel Coronavirus Mutations and Variants - What Do They Mean for Us?” there are currently three COVID-19 mutations or variants that are of concern: the United Kingdom variant, the South African variant, and the Brazilian variant. As Dr. Edwards stated, the United Kingdom variant is expected to become the dominant form of the virus in the US next month – in March 2021.

The FDA’s newest Guidance will allow for booster shots to be made available once manufacturers have tested a modified vaccine in a few hundred research subjects over a couple of months rather than the current requirements that are necessary for new vaccines which require testing in thousands of research subjects over several months.

While FDA says that “available information suggests that the FDA-authorized vaccines remain effective in protecting the American public against currently circulating strains of SARS-CoV-2,” there is some concern that the variants will spread very fast and might very well lower the immunity protection that the existing vaccines provide. As a result, vaccine manufacturers are rushing to develop second-generation booster shots to combat these variants.

In its new Guidance (which updates an October 2020 Guidance that sets forth requirements for Emergency Use Authorizations - EUAs), the FDA provides recommendations to those vaccine developers who have already received (or have filed or are about to file) EUAs for their COVID-19 vaccines and are seeking to amend their EUA to address the new variants.

The new Guidance provides for a streamlined mechanism for existing vaccine manufacturers to obtain authorization booster shots for the new variants. On manufacturing information, FDA expects that this will remain generally the same for an authorized vaccine and the modified vaccine candidate from the same manufacturer and therefore it need not be provided in any great detail in any amended EUA. For clinical data, the guidance recommends that effectiveness be supported by data from clinical immunogenicity studies, which would compare a recipient’s immune response to virus variants induced by the modified vaccine against the immune response to the authorized vaccine. Studies would only need to be conducted in a single age group and the results could be extrapolated to other age groups. Manufacturers are also encouraged to study the modified vaccine in both naïve (non-vaccinated) individuals and in individuals previously vaccinated with the authorized vaccine. For safety, FDA states that assessments need only occur daily for at least seven days after the study vaccination, though it is recommending longer-term assessments be conducted to see if serious adverse events occur.

The Guidance can be found here.