The Centers for Disease Control and Prevention is ultimately siding with the Food and Drug Administration (FDA) instead of its own advisory committee in recommending that certain populations get a booster shot of the Pfizer vaccine for COVID-19.
The current process for how formal vaccine booster recommendations are issued include a journey from an advisory panel at the FDA to an advisory panel at the CDC and then final sign off by CDC's director.
"This scientific process goes from an advisory committee at the FDA, to the authorization of the FDA, to an advisory committee at the CDC and then recommendations from the CDC. It's a very transparent, scientific, public process and I listened intently," CDC Director Dr. Rochelle Walensky told ABC News Sept. 27.
The CDC's committee, Advisory Committee on Immunization Practices (ACIP), evaluates the safety and effectiveness of the vaccine when given at specific ages, severity of the disease, number of people who get the disease if there is no vaccine, how well a vaccine works for people of different ages and how practical the recommendations are put into practice.
The committee voted Sept. 23 against authorizing boosters for those in high-risk transmission environments (like nurses and teachers), citing that the recommendation is too broad and would enable even young people to unnecessarily get a booster.
As part of the established process, the final decision on the recommendation ultimately comes down to Walensky. Her decision aligned with the FDA's Sept. 22 amendment of its emergency use authorization of the Pfizer vaccine to allow a single booster dose to be administered at least six months after completion of the primary series for certain individuals.
"In a pandemic, even with uncertainty, we must take actions that we anticipate will do the greatest good," Walensky told ABC. "While today’s action was an initial step related to booster shots, it will not distract from our most important focus of primary vaccination in the United States and around the world."
CDC said the agency decided on this recommendation by analyzing recent data on immunity.
“Delta variant may need a very robust antibody response to protect against it. The combination of a waning immunity and the delta variant is what has led us to consider this need for boosters or third doses,” Dr. Peter Marks, director of FDA’s Center for Biologics Evaluation and Research (CBER), said during a Sept. 15 virtual event.
Although COVID-19 vaccination for adults aged 65 years and older remains effective in preventing severe disease, recent data suggest vaccination is less effective at preventing infection or milder illness with symptoms.
Evidence also shows that among health care and frontline workers, vaccine effectiveness decreases over time, due to the combination of decreasing protection as time passes since getting vaccinated as well as the greater infectiousness of the delta variant.
"Data from a small clinical trial show that a Pfizer-BioNTech booster shot increased the immune response in trial participants who finished their primary series six months earlier. With an increased immune response, people should have improved protection against COVID-19, including the delta variant,” CDC said in a press announcement.
Moving forward, both CDC and FDA will continue to evaluate data to determine how and when to expand distribution of both the primary series of the vaccine, as well as boosters. CDC also plans to evaluate potential booster doses for the Moderna and Johnson & Johnson COVID-19 vaccines.
“[The CDC advisory committee] only reviewed data for the Pfizer-BioNTech vaccine. We will address, with the same sense of urgency, recommendations for the Moderna and Johnson & Johnson vaccines as soon as those data are available,” Walensky said in a CDC statement.
Also on the horizon, Pfizer-BioNTech plans to ask for authorization of a COVID-19 vaccine for some children under 12, Pfizer Chairman and CEO Albert Bourla told ABC News Sept. 26. Once the company submits its data for review, it will have to pass through both FDA and CDC’s committees for evaluation.
"We are all enthusiastically awaiting these data," Walensky said during her interview with ABC. "As soon as they get submitted to the FDA, I know the FDA is urgently planning to review these data, it will go from the FDA to the CDC, and we will review it with similar urgency ... I'm hoping in the order of weeks."