Will we need COVID-19 booster shots?
Data suggest that the messenger RNA-based COVID-19 vaccines developed by Pfizer-BioNTech and Moderna provide protection from infection for at least 6 months.
Recent comments made by the heads of two of those companies raised questions about whether people may need booster doses of the vaccines to combat variants and prolong protection against wild-type SARS-CoV-2.
Pfizer CEO Albert Bourla, DVM, PhD, told CNBC that people are “likely” to need a third dose of the Pfizer-BioNTech vaccine within a year, and may even need an annual shot.
Similarly, Moderna CEO Stéphane Bancel, MSc, said in a virtual event hosted by CVS Health that people who received the Moderna vaccine will “likely” need a third dose after 6 to 12 months, according to CBS News. Bancel said the booster will be available in the U.S. by the fall and will be a combination shot meant to protect against COVID-19 and seasonal influenza.
C. Buddy Creech, MD, MPH, associate professor of pediatrics and director of the Vanderbilt Vaccine Research Program at Vanderbilt University Medical Center, said it is too early to tell what role booster doses of COVID-19 vaccine may have in navigating the pandemic, and what the best timing of the shots would be.
“What we do know is that we need to be prepared,” Creech told Healio.
He underscored the importance of emerging variant strains of SARS-CoV-2 and new variants that could emerge should transmission be left unchecked. The B.1.1.7 variant, first identified in the United Kingdom, has already overtaken wild-type SARS-CoV-2 to become the dominant strain in the United States.
“Fortunately, the current vaccination strategy addresses this particular variant,” Creech said. “What we don’t know is whether future variants that emerge will be as effectively controlled with current vaccines. Therefore, work is underway to modify our vaccines so that we have even better coverage against newer variants that are beginning to circulate, such as the B.1.351 variant first identified in South Africa.”
Study participants have already begun receiving a variant-specific COVID-19 vaccine developed by Moderna that targets the B.1.351 variant, the NIH announced recently.
“At the end of the day, SARS-CoV-2 may become our fifth endemic coronavirus. Since we do not know precisely what disease looks like following immunity — following either natural infection or vaccination — we do not know what the best approach will be,” Creech said.
During a recent appearance on Meet the Press, National Institute of Allergy and Infectious Diseases Director and chief presidential medical advisor Anthony S. Fauci, MD, said public health — and not pharmaceutical companies — will determine the need for a booster dose of COVID-19 vaccine.
He explained that researchers will be able to predict when protection is so low that breakthrough infections are likely.
“When that happens, clearly, you're going to see a recommendation for a booster,” he said.
Paul A. Offit, MD, director of the Vaccine Education Center at The Children's Hospital of Philadelphia, said vaccine makers “have been ramping up production since the beginning with an understanding there may well need to be booster doses.”
He does not agree with Bourla and Bancel that a booster dose will likely be needed, however — at least not so soon.
“The nature of the titer of neutralizing antibodies that seems to be induced after certainly the second dose of messenger RNA vaccine — or even a single dose of the Johnson & Johnson vaccine — predicts longer term protection,” Offit told Healio. “More importantly, I think that the sort of vigorous T-cell response that appeared to be induced after either the second dose of the mRNA vaccines or one dose of Johnson & Johnson vaccine also predicts longer protection. So, we don't know this yet ... but I'm going to guess that it's going to last longer than a year.”
Creech said it was too early to know for sure “exactly what we will have to do to control the severity and frequency of COVID-19.”
However, as more and more individuals develop immunity, preferably through vaccination, we will be in a better position to control this pandemic,” he said.
Fauci said federal health agencies will likely have the necessary data to make a decision on booster doses by the end of summer, when companies are around 1 year since their phase 3 trials.
“I think by the end of the summer, the beginning of the fall, we'll know, and we'll have a pretty good idea whether we'll need the dose,” he said.
Cerullo M. Moderna plans to have third vaccine booster shot ready by fall. April 19, 2021. Accessed April 21, 2021. https://www.cbsnews.com/news/moderna-covid-vaccine-booster-shots/.
Chow D. Covid-19 booster shot likely needed within 12 months, Pfizer's CEO says. April 15, 2021. Accessed April 21, 2021. https://www.nbcnews.com/science/science-news/covid-19-booster-shot-likely-needed-12-months-pfizers-ceo-says-rcna692.
Moderna. Moderna provides clinical and supply updates on COVID-19 vaccine program ahead of 2nd annual vaccines day. https://investors.modernatx.com/news-releases/news-release-details/moderna-provides-clinical-and-supply-updates-covid-19-vaccine. Accessed April 21, 2021.
Pfizer. Pfizer and BioNTech confirm high efficacy and no serious safety concerns through up to 6 months following second dose in updated topline analysis of landmark COVID-19 vaccine study. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-confirm-high-efficacy-and-no-serious. Accessed April 21, 2021.