Pharmacist Karen Flynn gives a second Moderna booster shot to...

Pharmacist Karen Flynn gives a second Moderna booster shot to her mother Joann Pangonis, of New Boston, Pa., at Morris Drug in Mahanoy City, Pa., on Friday afternoon, April 1, 2022. (Jacqueline Dormer/Republican-Herald via AP) Credit: AP/Jacqueline Dormer

A fourth dose of the Pfizer-BioNTech COVID-19 vaccine provides "only short-term protection and a modest absolute benefit" against omicron infections in older adults but is effective in preventing severe illness, hospitalization and death, according to a new study from Israel.

The analysis, published Tuesday in the New England Journal of Medicine, tracked 1.25 million Israelis 60 or older who received their second booster from Jan. 10 through March 2 — a period when omicron rapidly spread throughout the population. 

The findings come a week after the U.S. Food and Drug Administration approved a second booster dose for Americans ages 50 and older and those who are immunocompromised who had their first booster at least four months prior.

"Protection against confirmed infection appeared short-lived, whereas protection against severe illness did not wane during the study period," researchers wrote.

          WHAT TO KNOW

  • A second Pfizer-BioNTech booster dose provides just short-term protection against omicron infection, according to a new study based on data out of Israel
  • But the findings, published in the New England Journal of Medicine, show the fourth shot provides continued protection against severe COVID illness
  • Area doctors said the data shows there's a benefit for older and immunocompromised Americans to get a second booster but that an additional shot may not be needed yet for healthy, younger individuals

Dr. Aaron Glatt, chair of the department of medicine at Mount Sinai South Nassau hospital in Oceanside, said the data shows a "slight benefit" for older and immunocompromised individuals to get a second booster.

"It's not absolute and it's not crystal clear that every single person should be getting a fourth dose," Glatt said. "But I do think, for people who are older and have underlying medical problems, it's reasonable to get a fourth dose."

Dr. Aaron Glatt outside Mount Sinai South Nassau at 1...

Dr. Aaron Glatt outside Mount Sinai South Nassau at 1 Healthy Way in Oceanside in 2020. Credit: Jeff Bachner

The study found that the second booster's effectiveness in preventing infection peaked after four weeks by a factor of 3.5 compared to those who received a single booster shot. But by the eighth week, "protection against confirmed infection wanes," the authors wrote.

The booster's protection against severe illness, however, did not decline in the six weeks after the fourth shot, researchers found. The rate of severe disease, for example, in the three-dose group was 3.5 times higher than those who received a second booster, the report found.

But the authors acknowledge the follow-up period was too short to determine how long protection against serious illness lasts.

Dr. Bruce Polsky, chairman of medicine and an infectious disease specialist at NYU Langone Hospital-Long Island, said the goal of vaccination is not to eliminate all infections but to prevent severe disease leading to hospitalization or death. He calls the findings "good news" and said it confirms the usefulness of a second booster.

"The vaccine is doing what it was intended to do in this population: prevent severe disease compared to the group who did not get the fourth shot," Polsky said. "It's encouraging in the sense that it supports what we've been saying, and should provide a degree of confidence in the population for which a fourth dose has been recommended that it's a good thing to do and will derive a benefit."

The study does not provide data on the booster's effectiveness among those under the age of 60 or who are unvaccinated. Previous research in Israel showed the second booster provided limited protection against infection among younger people.

"Overall, these analyses provided evidence for the effectiveness of a fourth vaccine dose against severe illness caused by the omicron variant, as compared with a third dose administered more than 4 months earlier," the authors wrote. "For confirmed infection, a fourth dose appeared to provide only short-term protection and a modest absolute benefit."

The report is likely to add fuel to the debate regarding the need for a second booster shot.

Federal regulators met Wednesday to discuss the potential need for annual boosters, similar to influenza, and whether to move forward with variant-specific vaccines. COVID has mutated repeatedly since the vaccine was created, reducing the shot's effectiveness in preventing infection, particularly against omicron, Polsky said.

"This vaccine was developed against the ancestral strain," of the virus, he said. "Which is a different virus in many respects."

To date, two-thirds of Americans have received at least one dose of the vaccine — and almost 90% of all New Yorkers, according to the CDC. But only 30% of Americans, and nearly 39% of New Yorkers, have received a booster shot, the data shows.

Glatt said it's still unclear if the second booster is needed for the entire population.

"For healthy, younger persons without underlying medical issues, I don't think it's as evident that the booster is needed," Glatt said.

The state's COVID positivity rate inched up again Tuesday to 3.2% on a 7-day average while the rate was 3.3% on Long Island, with 266 new cases in Nassau and 178 in Suffolk, according to the state Health Department. Six New Yorkers succumbed to COVID Tuesday, including one in Nassau.

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