That protection seems to be slipping, shows a new study led by the National Institute of Allergy and Infectious Diseases’ Infectious Diseases Clinical Research Consortium.
According to the June study, most boosters—whether from Pfizer, Moderna, or Johnson & Johnson—did offer strong protection against Omicron. Specifically, they elicited high levels of neutralizing antibodies against an early strain of Omicron, BA.1. However, by three months after the booster shot, antibody levels decreased between 2.4- and 5.3-fold.
The data also shows that later types of Omicron—BA.2.12.1 and BA.4/BA.5—were 1.5 and 2.5 times less susceptible to booster shot neutralization than BA.1, respectively. According to the authors, the findings suggest that Omicron is gaining increasing resistance to vaccines over time.
“It’s data like this that drove the Food and Drug Administration (FDA) and the vaccine manufacturers to look at vaccines that contained Omicron spike protein,” Andy Pekosz, PhD, virologist at the Johns Hopkins Bloomberg School of Public Health, told Verywell.
Last month, the FDA advised vaccine manufacturers to develop modified, bivalent vaccines that include the Omicron BA.4/BA.5 spike protein component in addition to the current vaccine composition. Pfizer-BioNTech and Moderna have already shared the data of their bivalent vaccine candidates with regulators.
These should provide stronger protection against Omicron and older variants in the fall, Pekosz said.
What Could This Mean for COVID Vaccination Schedules?
It’s possible that the U.S will eventually transition to a vaccine schedule similar to its annual approach to influenza, based on the evidence and experience with COVID-19 thus far, Mark Loafman, MD, MPH, a family physician and chair of the Family and Community Medicine Department at Cook County Health in Chicago, told Verywell.
The flu shot is formulated annually based on the strain that is projected to be in circulation for the flu season. However, COVID-19 is different because it does not follow a fixed seasonal cycle that comes and goes.
It’s important to find out whether we’ll continue to need regular COVID-19 boosters in the long run, and if so, whether once a year will be the right schedule, Loafman said.
“Overall, COVID-19 vaccines are saving lives and preventing serious illness, especially for those who are boosted,” he said. “While it is disappointing that vaccines and boosters are not stopping infection as had been hoped, they are still a miracle in terms of preventing death and serious illness.”
Loafman emphasized that the protective benefit of vaccines persists even though antibody levels decline a few months after a dose is administered. But we have yet to know how low is too low, or how that may vary person by person.
Time and more clinical trials will help answer these questions.
“The boost in immunity to Omicron induced by the standard booster will provide protection and it will help your immune system respond faster to an Omicron infection,” Pekosz said. “If you are in a booster-eligible population, you should get it now and then see what the official guidance will be for the fall bivalent booster.”
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.
