Experts: Too soon to know whether COVID vaccine booster needed
It remains unclear whether people will need to receive annual doses of the COVID-19 vaccine, but it seems possible that even fully vaccinated people will need at least one more dose, experts said.
“It looks pretty likely that in fall we are going to need a booster that includes any variants that have been identified,” said Dr. Zane Saul, chief of infectious disease at Bridgeport Hospital.
Since the vaccines entered the market late last year, there has been discussions about how long the immunity produced by these shots would last, and whether vaccinations would need to administered annually like the flu shot .
Right now, a lot is still unknown, said Dr. Paul Nee, an infectious disease specialist with Danbury Hospital and COVID-19 clinical coordinator for Nuvance Health, which includes hospitals in Danbury, New Milford, Norwalk and Sharon.
“We just don’t know a lot of answers to questions about the durability,” of the vaccine response, Nee said. “All the science coming out is new and it’s changing — day by day, in some cases.”
Even the Centers for Disease for Control and Prevention has said that
“we don’t know how long protection lasts for those who are vaccinated . ... Experts are working to learn more about both natural immunity and vaccine-induced immunity.”
Nee said one concern is that immunity to coronaviruses — a group that includes not just COVID-19, but also less serious illnesses, such as the common cold — can wane over time.
“Immunity doesn’t last very long with coronaviruses,” said Lisa Cuchara, professor of biomedical science in Quinnipiac University’s School of Health Sciences. She added that there is some indication that vaccine-based immunity can last longer than natural immunity, which stems from antibodies produced after someone has fought off an illness.
Another factor to consider is how well the current vaccines protect against the variants of COVID-19 that have popped up in recent months. Both Pfizer-BioNTech and Moderna have announced that they are launching studies of booster shots of each companies’ two-dose vaccines, mainly to address the variants, including the B.1.351 variant that first showed up in South Africa.
Pfizer said the study of its proposed booster would draw on participants from its clinical study, who would be offered a booster shot 6 to 12 months after receiving their initial twodose regimen. The study would investigate “the effect of a booster on immunity against COVID-19 caused by the circulating and potential newly emerging SARS-CoV-2 variants.”
Pfizer and BioNTech also are in discussions with regulatory authorities, including the U.S. Food and Drug Administration about a clinical study that would evaluate a variant-specific vaccine.
“This study would use a new construct of the Pfizer-BioNTech vaccine based on the B.1.351 lineage, first identified in South Africa,” a company press release read.
Moderna has announced that it is evaluating three different approaches to boosting its vaccine, including a variant-specific vaccine based on the South African strain. It is also studying a third dose of its existing vaccine, as well as a vaccine that combines the existing vaccine with the variant-specific vaccine.
It will likely be several months before those studies are complete. In the meantime, experts think it’s too soon to know when a booster will be needed or when it will be delivered.
“It’s all speculation,” Saul said.