A New Wave of Immunity: Updated COVID-19 Vaccines Target Emerging Variants
A summer surge of COVID-19 infections has prompted the US Food and Drug Administration (FDA) to approve updated mRNA vaccines that specifically target currently circulating variants of the coronavirus. These vaccines, developed by Moderna and Pfizer/BioNTech, represent a critical step in the ongoing battle against the evolving virus.
Targeting the Latest Threat: The new vaccines focus on a variant of Omicron called KP.2, one of several "FLiRT variants" responsible for the current surge in cases. FLiRT variants are known for their ability to evade the immune system, making them highly transmissible. “Given waning immunity of the population from previous exposure to the virus and from prior vaccination, we strongly encourage those who are eligible to consider receiving an updated Covid-19 vaccine,” stated Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research.
Boosting Protection: The updated vaccines, formulated for the 2024-2025 season, are designed to bolster protection against hospitalization and death due to COVID-19. Highlighting the urgent need for vaccination, the CDC reports that over 916,300 individuals were hospitalized and more than 75,500 died from COVID-19 in the US alone during 2023. Vaccination is also a crucial tool in mitigating the risk of long COVID, a debilitating condition that can persist for months after infection.
The Importance of Frequent Updates: Similar to the influenza virus, SARS-CoV-2 is constantly evolving and mutating. This ongoing evolution necessitates regular updates to the COVID-19 vaccines to ensure continued effectiveness. Elizabeth Hudson, regional chief of infectious disease at Kaiser Permanente Southern California, emphasizes the rapid pace of SARS-CoV-2 evolution, stating, “It’s spinning through variants more quickly than what we’re seeing with flu.”
Navigating the Evolving Landscape: The FDA’s decision to target KP.2 comes after an advisory committee recommended that manufacturers develop updated vaccines for the fall. Initially, recommendations focused on the JN.1 lineage, but the agency later shifted its guidance based on emerging data, selecting KP.2 as a more appropriate target due to its prominence among circulating variants. This underscores the dynamic nature of the virus and the need for ongoing scientific assessment to guide vaccine development.
A Continuous Cycle of Adaptation: The previous version of the COVID-19 vaccine, approved in September 2023, targeted the XBB.1.5 variant, which dominated the first half of 2023. However, the virus’s rapid evolution has rendered the previous vaccine less effective against the currently circulating FLiRT variants, which are known for their increased transmissibility and immune evasion capabilities.
Navigating Vaccine Timing: While the CDC encourages everyone 6 months and older to receive the updated vaccine, it recommends a three-month delay for individuals who have recently had a COVID-19 infection. This delay allows the body’s natural immune response to fully develop, maximizing the benefit of vaccination.
Balancing Protection and Timing: Even though the peak of respiratory virus infections typically occurs in the winter, COVID-19 exhibits a bi-seasonal pattern, with significant surges occurring both in the winter and summer months. The current summer surge is attributed to the emergence of new variants and waning immunity from previous vaccines. “Any natural immunity or vaccine immunity from 2023 has reached a nadir,” says Hudson. “This is sort of a perfect storm for a more infectious form of Covid.”
The Role of Medical Professionals: Rosha McCoy, a pediatrician and senior director of healthcare affairs at the Association of American Medical Colleges, emphasizes the importance of consultation with healthcare providers regarding vaccine timing. While late September and October are generally recommended for vaccination to provide protection throughout the winter months, individuals at high risk or facing upcoming exposures may need to get vaccinated sooner.
A Call to Action: The approval of updated COVID-19 vaccines underscores the importance of continued vigilance and adaptation in the fight against this evolving virus. Staying informed about current recommendations, consulting with medical professionals, and taking advantage of available vaccine updates are crucial steps in safeguarding individual and community health. As the virus continues to adapt, so too must our preventive strategies, ensuring that we remain one step ahead in the ongoing battle against COVID-19.
