Pfizer and Moderna vaccines attacking Omicron given the green light by the FDA
The FDA approved on Wednesday, 31 August, the new version of Pfizer and Moderna’s COVID-19 vaccines targeting the Omicron variant, hoping to contain a new wave of infections feared this winter.
Pfizer and Moderna and their two updated vaccines are approved for a booster dose, starting at age 12 for Pfizer’s vaccine and at age 18 for Moderna’s vaccine, the U.S. Food and Drug Administration said in a statement. This new generation of anti-COVID vaccine, known as bivalent, targets both the original strain of coronavirus and the BA.4 and BA.5 lineages of the Omicron variant. The latter lineage currently accounts for nearly 90% of infections in the US.
“A new wave is expected when we spend more time indoors this fall and winter,” FDA chief Robert Califf warned at a press conference, saying it was “anticipating” this rise in infections. Even though the virus has largely faded from the daily lives of Americans, the US is still recording some 80,000 new cases and 400 deaths from COVID-19 every day. Earlier this summer, the US Department of Health announced that it had purchased 105 million of these further doses from Pfizer and 66 million from Moderna.
The two updated vaccines still need to be recommended by the Centers for Disease Control and Prevention (CDC) before injections can begin. An independent panel of experts is to be convened by the CDC to discuss the matter on Thursday, 1 September. Then the head of the agency, Rochelle Walensky, will be responsible for giving the final go-ahead.
Pfizer and Moderna have indicated that the new doses are ready to be shipped, potentially available next week in the country. The challenge will be to convince Americans to take the new shots since only about half of those eligible have already had their first booster dose.
The initial vaccination program will continue to be offered with the previous vaccines, for the time being, to provide a “baseline” of immunity, Califf said. Updated boosters will be available for two months after receiving a previous dose (booster or initial vaccination). The dosage is 30 micrograms for Pfizer and 50 micrograms for Moderna.
The vaccines currently in circulation were, for the moment, based solely on the initial strain of the virus that appeared in Wuhan, China. Still, they have gradually proved less effective against variants that have occurred over time due to the rapid evolution of the virus.
The FDA’s approval is based partly on clinical trials to evaluate another updated vaccine version, using the BA.1 lineage. This version of Moderna’s vaccine was licensed in the UK in mid-August. So far, vaccines specifically using BA.4 and BA.5 have only been evaluated in pre-clinical animal studies.
But the FDA reiterates that the change in strain threatens the safety of the vaccines. “What we do here is what we do every year for the flu vaccine,” said Peter Marks of the FDA. Some US experts, however, questioned the extent to which these updated vaccines could be more effective, as this can only be measured through clinical trials.
“The hope is to “restore” a level of immunity similar to that conferred by the vaccines when they were first introduced, and to provide a “longer duration of protection” so that boosters do not have to be repeated too often, said Peter Marks. Studies will be conducted to assess the actual effectiveness.
Asked about the need to include the young population in this large-scale booster campaign, Marks said that these vaccines could help protect against “long COVID,” which affects all ages. Pfizer and Moderna have also submitted an application to the European Medicines Agency (EMA) for an updated vaccine version.