Major changes are expected for COVID-19 vaccines in the upcoming autumn.
Despite the fact that the original strain of the coronavirus, which initiated the global pandemic, has been surpassed by numerous mutated variants due to the virus’s rapid evolution, the current vaccines still contain the original strain.
The scientific advisers of the Food and Drug Administration (FDA) stated on Thursday that the next series of shots in the United States should specifically target the latest dominant variants, specifically the XBB branch of the omicron family, which is prevalent worldwide.
The FDA will have the final say on this matter. During the meeting, vaccine manufacturers indicated that they could develop updated vaccines within a matter of months, depending on the specific variant.
Although infection rates have been declining, Dr. Peter Marks, the FDA’s vaccine chief, expressed concern about the potential resurgence of the virus during the approaching winter. He emphasized that there is a risk of another wave of COVID-19 as the virus continues to evolve, population immunity weakens, and people spend more time indoors during the winter season.
Here’s what you need to know:
Why are we having another round of shots? The FDA had previously indicated that a revised COVID-19 vaccine would be available in the fall, similar to the annual flu shot. Despite a significant portion of the population having been infected or received at least one round of vaccinations, new variants of the coronavirus continue to emerge.
The current vaccines being used in the U.S. are a combination of Pfizer and Moderna shots that provide protection against the original strain as well as the BA.4 and BA.5 variants of omicron, which were prevalent last year. However, only 17% of Americans have received this combination booster shot.
Although the FDA authorized an additional booster dose for seniors and high-risk individuals this spring, most people will have a significant gap between their last shot and the upcoming fall period.
While the existing vaccines still offer protection against severe illness and death, the efficacy gradually diminishes over time. Furthermore, the vaccines have shown limited effectiveness against milder infections even before the virus evolved into the current XBB variants.
“We need a better vaccine. We should be updating it,” emphasized Dr. Eric Rubin, an infectious disease doctor at Brigham and Women’s Hospital in Boston, expressing the need for vaccine improvement.
In the past, when regulators were faced with the challenge of updating the vaccine, a combination shot seemed like the most prudent choice. At that time, omicron was relatively new, and it was uncertain how long it would persist or if future changes in the coronavirus would resemble the original strain.
However, retaining the original strain in the vaccine has a drawback known as “imprinting.” With repeated exposure to the original strain, people’s immune systems tend to recognize and mount a stronger response against it compared to the newly introduced component of the booster dose.
The FDA advisory panel, along with the World Health Organization’s vaccine advisers and European regulators, agreed that the fall COVID-19 shot should specifically target XBB variants. This consensus was reached recognizing that the variants circulating now are likely to undergo further mutations by the winter season.
Choosing the specific XBB variant to target presents a challenge, similar to the process of determining the composition of the annual flu vaccine. The FDA has identified three XBB subtypes as the primary choices for the strain to be included in the vaccine. Vaccine manufacturers have already been working on developing formulations that target the XBB variants. During the meeting, there was agreement that the most common version of XBB, known as XBB.1.5, should be the target variant for this fall’s vaccine.
The question remains as to how many shots will be recommended. Older adults and individuals with weakened immune systems, who continue to have the highest hospitalization rates from COVID-19, may be advised to receive a single fall shot or possibly more. Additionally, there is uncertainty regarding the number of doses that will be recommended for young children who have not yet been vaccinated.
Ultimately, the final recommendations on who should receive the updated shot and when will be made by the Centers for Disease Control and Prevention (CDC).