FDA Vaccine Committee Discusses the Future of COVID-19 Boosters

Today, the US Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) met to discuss considerations for COVID-19 vaccine strain selection and booster doses.

As immunity wanes over time and with new infectious variants, the committee discussed how to proceed with COVID-19 vaccinations and booster doses. Some of the major questions the committee debated throughout the day included: Should there be 1 universal strain approved for COVID-19 boosters? Is it sustainable to continue regularly getting boosters? How active of a role should VRBPAC play in leading COVID-19 booster decisions? VRBPAC examined COVID-19 infection and hospitalization data to inform future booster dose recommendations.

LCDR. Ruth Link-Gelles, PhD, gave a presentation on the current status of vaccine efficacy across various stages of vaccination and COVID-19 variants. Link-Gelles noted that the BA.2 variant is now responsible for approximately 72% of new COVID-19 cases in the US. “The patterns here show a clear benefit of a third dose over a second dose during Omicron,” Link-Gelles concluded.

However, breakthrough infections are occurring even in individuals who are fully vaccinated and boosted. Israel has begun rollout of a fourth mRNA vaccine dose, and VRBPAC examined this initiative as a case study with the potential to guide US booster decisions. To expound upon the real-world results, Sharon Alroy-Preis, MD, MPH, MBA, the director of the Public Health Services Ministry of Health in Jerusalem, Israel, shared the study findings.

Approximately 50% of Israeli adults 60 years and older received a fourth dose of the Pfizer-BioNTech vaccine, with a total of 753156 second booster doses administered. Among these, there were 442 mild reports and 12 serious reports of adverse events. Alroy-Preis noted that the vast majority of adverse events were systemic, such as fever.

The committee debated whether COVID-19 vaccines should be administered yearly, like the influenza vaccine. VRBPAC members frequently used the influenza vaccine to model expected vaccine efficacy, saying that breakthrough infections are to be expected. Some experts pointed to data suggesting that although COVID-19 vaccination efficacy decreases over time and with the emergence of highly infectious variants, protection against hospitalization and death remains robust.

One VRBPAC panelist pointed out that the committee should be leading the COVID-19 vaccine strain decisions, rather than manufacturers choosing a strain and then seeking approval. VRBPAC noted that the original Wuhan strain used in vaccines is still effective against COVID-19 mutations like Delta and Omicron. Changing the COVID-19 vaccine strain composition is a complicated process that requires extensive research and discussion. VRBPAC reiterated that presenting a clear, unified message to guide public health decisions remains the highest priority.

The committee did not vote on any recommendations today, but the consensus was that any available clinical trial data should be prioritized when making future decisions.