Food and Drug Administration scientists on Tuesday declined to take a stance on whether or not booster shots of the Covid-19 vaccine should be supported by Moderna, saying the data shows two doses are still enough to last in the U.S. protect against serious illness and death

“Some real-world efficacy studies have shown that the effectiveness of the Moderna COVID-19 vaccine wears off over time against symptomatic infection or against the Delta variant, while others have not,” they wrote in a 45-page publication Document published on the Agency’s website. “However, the overall data suggests that COVID-19 vaccines currently licensed or approved in the United States still offer protection from severe COVID-19 illness and death in the United States.”

FDA staff also took no position on Pfizer’s Covid Booster vaccinations last month. That hasn’t stopped the Agency’s Advisory Committee on Vaccines and Related Biological Products from recommending third vaccinations. The committee rejected Pfizer’s original plan to distribute the boosters to everyone aged 16 and over, narrowing it down to those most at risk from Covid, including the elderly and those with other health problems. FDA officials later expanded eligibility to include those who worked or lived in environments that put them at high risk of exposure, such as healthcare workers and grocery stores.

Maryland National Guard specialist James Truong (L) administered Jan.

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The report by FDA scientists is set to brief the committee, which will meet on Thursday to review Moderna’s application to clear the adult Covid booster doses. The published documents give an insight into the agency’s perspective on third shots.

The meeting comes less than a month after U.S. regulators approved Covid booster shots of Pfizer and BioNTech’s vaccine for a wide variety of Americans, including the elderly, adults with pre-existing medical conditions, and those in high-risk environments like health and Grocery store worker.

The FDA advisory group is due to discuss data on the safety and effectiveness of the booster vaccination of Moderna in adults on Thursday and that of Johnson & Johnson on Friday. The agency could make a final decision within days of the meetings and hand it over to the Centers for Disease Control and Prevention and their Vaccine Advisory Committee, expected to make their own decision next week.

Moderna filed for FDA approval for a booster dose on September 1. The company said the results are based on a clinical study of about 170 adults, fewer than the 318 people screened for the Pfizer booster. Moderna said a third shot at half the dose used for the first two injections was safe and elicited a stronger immune response than after the second dose in its Phase III clinical trial.

Moderna is asking the FDA to release boosters for the same vulnerable groups eligible to receive the third dose of Pfizer – people 65 years of age and older, adults at high risk of severe Covid cases, and workers over 18 with an increased chance of occupational exposure towards the virus.

The side effects of Moderna’s boosters were similar to those after the second dose, the company wrote in a separate document released Tuesday by the FDA. Most of the side effects were of minor severity and Moderna reported no cases of rare heart inflammation, myocarditis, or pericarditis in subjects for up to 29 days after receiving the booster.

The Biden government hopes the extra dose will continue to provide long-term and permanent protection from serious illness, hospitalization, and death for the U.S. population as the fast-paced Delta variant continues to spread.

The exposure led to an increase in hospital admissions in the US, mainly among the unvaccinated. Still, some vaccinated Americans have suffered what are known as breakthrough infections and, according to the CDC, only more than 19,000 of them – less than 1% – had been hospitalized or died of Covid by September 20.