The FDA decisions mark a big step toward expanding the US booster campaign.
The US drug regulators on Monday announced the extension of booster privileges to Johnson&Johnson and Moderna, and allowed the mix-and-match of COVID vaccines—anyone can now opt for booster inoculations from a different brand that they were initially vaccinated with. The Food and Drug Administration (FDA) decisions mark a big step toward expanding the US booster campaign, which began with extra doses of the Pfizer vaccine last month. The CDC (Centre for Disease Control) will iron out the finer points of who can get what vaccine and when in a meeting to be held today.
The decision was widely expected. Preliminary results from a government study of different booster combinations found an extra dose of any type increased the levels of virus-fighting antibodies regardless of the brand people first received. But recipients of the single-dose J&J vaccination had the most dramatic response—a 76-fold and 35-fold jump in antibody levels, respectively, shortly after either a Moderna or Pfizer booster, compared to a four-fold rise after a second J&J shot.
The latest moves would expand by tens of millions the number of Americans eligible for boosters and formally allow mixing and matching of shots making it simpler to get another dose, especially for people who had a side effect from one brand but still want the proven protection of vaccination.
What are the FDA specifics?
Specifically, the FDA authorised a third Moderna shot for seniors and others at high risk from COVID-19, because of their health problems, jobs or living conditions, six months after their last shot. One big change: Moderna's booster will be half the dose that is used for the first two shots, based on company data showing that was plenty to kickstart immunity again. For J&J's single-shot vaccine, the FDA said all US recipients should get a second dose at least two months following their initial vaccination. The FDA rulings differ because the vaccines are made differently, with different dosing schedules and the J&J vaccine has consistently shown a lower level of effectiveness than either of the two-shot Moderna and Pfizer vaccines.
A recent study in Sweden showed that people who received a first dose of the Oxford-AstraZeneca COVID-19 vaccine, followed by an mRNA vaccine shot, had a lower risk of infection compared to those immunised with both doses of the AstraZeneca preventive.
In the main analysis, about 7,00,000 individuals were included. During a 2.5-month average follow-up period after the second dose, the study showed a 67 per cent lower risk of infection for the combination of AstraZeneca and Pfizer vaccine shots. There was a 79 per cent lower risk of infection for AstraZeneca and Moderna vaccine shots, compared to unvaccinated individuals, the researchers said. For people having received two doses of the AstraZeneca vaccine, the risk reduction was 50.