The Biden administration has maintained that the third shot is not necessary.
A new study is making a further case for COVID-19 booster shots, but public health experts are still skeptical of the need.
In the study, which has not been peer-reviewed or published in a medical journal, researchers from Pfizer found that the company’s two-dose vaccine produced a 96 percent efficacy rate against symptomatic COVID-19 two months after the second shot, but the protection fell every two months after that coming to about 83.7 percent efficacy after four to six months.
This is part of the company’s intended push to have a booster shot of their vaccine, BNT162b2, approved by the Food and Drug Administration (FDA).
Earlier in July, Pfizer announced that a third dose of the vaccine given six months after the second dose has a consistent tolerability profile and elicits high neutralization titers five or 10 times higher than the primary doses.
The impetus for speculation about booster shots is the rise of the Delta variant of COVID-19 which is now the most dominant strain in the U.S. The variant is more transmissible and has led to an uptick in breakthrough cases among the fully-vaccinated population.
This has led the Centers for Disease Control and Prevention (CDC) to recommend that people fully vaccinated against COVID-19 re-don their masks indoors at public spaces in parts of the country seeing large outbreaks of the disease.
President Joe R. Biden’s administration, though, is still resistant to recommending booster shots. A joint statement from the CDC and FDA denied the need for the additional vaccinations.
“Americans who have been fully vaccinated do not need a booster shot at this time. FDA, CDC, and NIH are engaged in a science-based, rigorous process to consider whether or when a booster might be necessary,” the statement says. “This process takes into account laboratory data, clinical trial data, and cohort data – which can include data from specific pharmaceutical companies, but does not rely on those data exclusively. We continue to review any new data as it becomes available and will keep the public informed. We are prepared for booster doses if and when the science demonstrates that they are needed.”