Moderna filed a request with the Food and Drug Administration (FDA) on Thursday to have a fourth dose of their COVID-19 vaccine approved for adults age 18 and above. Earlier on Tuesday, Pfizer with partner BioNTech also requested to have the FDA approve the fourth dose of vaccines for people aged 65 above, USA Today writes.

Moderna and Pfizer Ask FDA to Authorize Fourth COVID-19 Doses against Omicron

The booster shot request filed by Moderna is more expansive than the one made by Pfizer, but Moderna said it is to enable the FDA to determine what classes of adults are most appropriate for the proposed doses. Without being specific, Moderna said it based the request on US and Israeli data, which revealed that the Omicron COVID-19 variant is spreading fast and with the potential to overcome third doses earlier administered.

In January 2022, Israel approved a fourth vaccine shot for people who are above age 18 and more at risk. A related study of over one million Israelis above the age of 60 showed that a fourth dose of the Pfizer vaccine provided double protection and that people are four times less likely to be critically ill from an infection, more than those with three shots.

Other research indicated that coronavirus vaccines such as those manufactured by Pfizer and Moderna begin to lose their efficacy three months after a third dose is received. This situation made vaccine critics and anti-vaxxers question the wisdom of vaccination and the efficacy of booster shots.

Public health and infectious disease experts said annual COVID-19 vaccine shots appear to be where the world is headed, just like yearly flu shots. Peter Marks, the FDA’s top vaccine regulator, said the federal health agency is open to yearly vaccinations if no other coronavirus variants emerge.

“Barring any surprises from new variants, maybe the best thing is to think about our booster strategy in conjunction with the influenza vaccine next fall, and get as many people as possible boosted then,” Marks said.

The FDA has not revealed if the requests will be entertained or if its expert panel will be asked to review them.