Now, the US Food and Drug Administration “is indeed continually looking at the emerging data on the pandemic and variants in the United States and overseas in order to evaluate the potential utility and composition of booster doses,” FDA spokesperson Alison Hunt wrote in an email to CNN on Friday.
She confirmed that although Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, has noted that there is still much uncertainty as to how the pandemic may further evolve, he also has said it is possible that a fourth dose might be recommended as we move into fall.
“As more data become available about the safety and effectiveness of COVID-19 vaccines, including the use of a booster dose, we will continue to evaluate the rapidly changing science and keep the public informed,” Hunt wrote. “Any determination that additional booster doses are needed will be based on data available to the agency.”
If or when the FDA authorizes a fourth dose for the public, the next step would be for the US Centers for Disease Control and Prevention to review the data before making a recommendation for use, as the agency has done for other coronavirus vaccine recommendations.
‘Vaccination and boosting will be critical’
The United States has seen significant improvements recently in Covid-19 cases, hospitalizations and deaths. As of Friday, cases were down 44% from the prior week, hospitalizations dropped 26%, and deaths were 13% lower, according to Johns Hopkins University data.
The “potential future requirement” for an additional boost or a fourth shot of the Pfizer/BioNTech or Moderna mRNA vaccines or a third dose of the Johnson & Johnson vaccine “is being very carefully monitored in real time,” Fauci said. “And recommendations, if needed, will be updated according to the data as it evolves.”
“For the immunocompetent people, a single booster shot continues to provide high levels of protection against severe disease caused by Omicron,” Fauci said Wednesday. “This should not be confused with the fact that for many immunocompromised people, already a second booster shot — namely a fourth dose of an mRNA — is recommended because of what we know about their poor response to the initial regimen.”
Meanwhile, vaccine makers continue to study fourth doses in broader populations.
‘We recognize the need to be prepared’
For that study, participants have been separated into three cohorts. One includes 600 people who got three doses of the current Pfizer/BioNTech coronavirus vaccine before enrolling in the study. As part of the research, they will receive either a fourth dose of the current vaccine or a dose of the Omicron-based vaccine.
“While current research and real-world data show that boosters continue to provide a high level of protection against severe disease and hospitalization with Omicron, we recognize the need to be prepared in the event this protection wanes over time and to potentially help address Omicron and new variants in the future,” Kathrin Jansen, senior vice president and head of vaccine research and development at Pfizer, said in the company’s announcement of the study.
With the Omicron variant dominant in the United States, vaccine effectiveness was 87% against Covid-19 emergency department or urgent care visits and 91% against hospitalizations in the two months after a third dose. Effectiveness fell to 66% and 78%, respectively, by the fourth month, the data showed.
“Nonetheless, the level of 78 is still a good protective area,” Fauci said Wednesday.
The research showing some waning immunity after a third dose has led to more discussion around if or when fourth doses could be needed.
“Just like with everything else, the health departments look at this data that’s coming out and wait for guidance from the CDC and from the drug manufacturers. The drug manufacturers have been monitoring vaccine effectiveness,” Lori Tremmel Freeman, chief executive officer of the National Association of County and City Health Officials, told CNN on Friday.
The timing for fourth doses not only depends on waning immunity “but also depends on whether we see any more variants emerge and what we discover in terms of additional vaccine effectiveness for any emerging new infections,” Freeman said.
If fourth doses are needed, “health departments would go into the mode of preparing to administer the fourth dose in the way they have done previous doses,” Freeman said. However, of greater concern among local public health officers is the slow — and declining — pace of people completing their third doses, she said.
“As time goes on, if there is the necessity of a fourth dose, we’re already behind with people getting the third dose,” Freeman said. “So all of a sudden, we could have a fairly large segment of the population that is not up to date on vaccines because they’re behind by two doses, potentially, and more people could get sick.”
