A study published Wednesday in the New England Journal of Medicine found that a fourth dose of the COVID-19 vaccine is “somewhat efficacious,” but still “immunogenic” and “safe.”

Authors of the study wrote that there was no significant difference in immune response or “in levels of omicron-specific neutralizing antibodies” between a third and fourth dose of the vaccine.

“Our results suggest that maximal immunogenicity of mRNA vaccines is achieved after three doses and that antibody levels can be restored by a fourth dose,” the authors said. “A fourth vaccination of healthy young health care workers may have only marginal benefits.”

The authors noted that they did not evaluate older and more immunocompromised individuals.

Pfizer CEO Albert Bourla said earlier this week that protection following a third dose “doesn’t last very long” and that a fourth shot "is necessary." According to WebMD, Bourla claims that the company has sent data to the Food and Drug Administration that will prove the necessity of a fourth dose.

The Wall Street Journal reports that the FDA may authorize a second booster shot in the near future.

Dr. Matthew Harris of Northwell Health says that “a more likely scenario is that the COVID-19 vaccines will become part of a seasonal vaccination akin to the influenza vaccine."

The Centers for Disease Control and Prevention suggests that everyone above the age of 12 get a third dose, and recommends the standard two-dose vaccine for people aged 5 to 11.