In the Midst of Summer Amid the surge in Covid-19 infections, the US Food and Drug Administration has just approved updated mRNA vaccines that better target the coronavirus variants currently circulating.
The updated vaccines from Moderna and Pfizer/BioNTech target a variant of Omicron called KP.2, one of several so-called FLiRT variants that together are responsible for the current wave of Covid. The modern vaccines are likely to take several weeks to reach pharmacies and doctors’ offices.
“Given waning immunity in the population due to prior exposure to the virus and prior vaccinations, we strongly encourage eligible individuals to consider receiving the updated COVID-19 vaccine,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in a statement Thursday.
The modern formula for 2024-2025 is expected to raise protection against hospitalization and death from Covid. In 2023, more than 916,300 people were hospitalized with Covid-19 and more than 75,500 people died from the virus in the US. Vaccination may also protect against long Covid, a chronic illness that lasts at least three months after infection.
US Centers for Disease Control and Prevention recommends modern vaccine all aged 6 months and olderregardless of whether you have ever been vaccinated against COVID-19.
Like the flu virus, SARS-CoV-2 is constantly changing. Just as flu vaccines are updated every year to match the changing makeup of the virus, Covid vaccines are also being updated. Elizabeth Hudson, regional chief of infectious diseases for Kaiser Permanente Southern California, says SARS-CoV-2 is changing faster than the flu virus, making it hard to predict which variants will be dominant when a vaccine is available. “The variants are circulating faster than what we see in the flu,” she says.
The FDA’s green lithe comes after an advisory committee unanimously recommended in June that manufacturers develop updated Covid vaccines for this fall. Based on evidence at the time, FDA advisers initially recommended that the modern vaccines be targeted at a line called JN.1, an offshoot of Omicron. But the agency updated its guidelinescalling on vaccine makers to instead focus on the KP.2 strain, a descendant of the JN.1 variant, to better match the circulating variants.
The previous version of the Covid vaccine got the green lithe from the FDA on September 11, 2023. That formulation targeted the XBB.1.5 variant, the dominant variant circulating in the U.S. in the first half of 2023. The virus has mutated significantly since then, and the FLiRT variants currently circulating are believed to be more contagious and more effective at evading the immune system than previous versions of the virus.
If you have recently had a COVID-19 infection, the CDC advises that you may want to consider delaying the vaccine dose by three months.
“In most cases, we recommend getting the Covid and flu vaccines in late September, October, to help people get through the winter months,” says Rosha McCoy, a pediatrician and senior director of health services at the Association of American Medical Colleges. “Of course, if someone is at high risk or will be at high risk, they may want to get the vaccine sooner.”
Typically, the largest increases in respiratory viruses occur in winter. But Covid tends to peak in both winter and summer, and the current summer surge is likely due to the emergence of modern variants and waning protection from previous vaccines.
“Any natural immunity or vaccine immunity since 2023 has bottomed out,” Hudson says. “This is kind of the perfect storm for a more contagious form of Covid.”