Vials of Pfizer BioNTech and Moderna Coronavirus Disease (COVID-19) vaccine labels can be seen in this illustration image dated March 19, 2021.

Given Ruvic | Reuters

A group of scientists from the Centers for Disease Control and Prevention said Wednesday that there is currently insufficient data to support the recommendation of Covid-19 booster vaccinations for the general population, but that more vulnerable groups such as the elderly or Transplant recipients may need an additional dose.

The CDC’s Covid-19 Working Group on Immunization Practices Advisory Committee did not rule out the possibility that the general population may need booster vaccinations if immunity to the vaccines wanes or a variant reduces the effectiveness of current vaccinations.

“Boosters can be needed for a large population. However, it could also be that the need for boosters of the Covid vaccine can only be demonstrated in some populations, “said Dr. Sarah Oliver, co-leader of the working group and medical epidemiologist with the National Center for Immunization and Respiratory Diseases of the CDC.

A study by researchers at Johns Hopkins University recently published in the Annals of Internal Medicine showed that booster shots can be beneficial for people with compromised immune systems. Oliver said the agency should monitor residents of long-term care facilities, the elderly, medical workers and the immunocompromised.

The working group recommended that the CDC only consider booster vaccinations “after signs of waning protection,” Oliver said, which means if the vaccines became less effective over time or if the antibodies to Covid waned over time. The agency could also consider using booster syringes if a variant emerges that significantly reduces the effectiveness of the vaccine.

“I have to agree with the interpretation of the working group in the sense that there is currently no data to support recommendations to support boosters,” said Dr. Sharon Frey, ACIP member and clinical director of the Center for Vaccine Development at Saint Louis University Medical School. “There is currently no evidence against the denial of protection.”

However, Frey said she was open to giving transplant patients a third chance or if infections increase in the general population, indicating many landmark cases in fully vaccinated individuals. There have been at least 3,729 breakthrough infections in the United States to date, leading to hospitalization or death, according to CDC data.

“I think the only thing we can do right now is if we see an increase in reinfection in people or new infections in people who have been vaccinated, that’s our indication that we need to act quickly,” Frey said.

Dr. Grace Lee, chair of the ACIP safety group and professor of pediatrics at Stanford University School of Medicine, also said she would like to see more evidence of breakthrough cases before recommending a booster vaccination.

“I’d like to see more certainty with the safety data if we talk about an increase before it is clear what the risk data will be,” said Lee. “When we see serious breakthrough cases, I think decision-making continues even when the security data is uncertain.”