close up of shot going into arm

The Pfizer-BioNTech COVID-19 vaccine diminishes in effectiveness as patients get older, according to a new study by researchers at UT Southwestern in Dallas.

While the vaccine limits transmission, hospitalization and death from the virus even by patients infected with variants, the research team said drug companies still need to step up their offense against COVID-19.

“The fact that these antibody functions decrease with age is one reason why the elderly are still more susceptible to severe illness with COVID-19 and highlights the need to develop different approaches for older, vulnerable individuals,” the study’s lead author, Lenette Lu, MD, PhD., said in a statement. 

The Food and Drug Administration approved the Pfizer-BioNTech vaccine in August of 2021. However, the emergence of new variants, such as delta and omicron, left the vaccine less effective in neutralizing SARS-CoV-2 and resulted in increased rates of infection. Still, vaccinated patients continued to be protected against severe disease and death even after being infected with the virus.

In the study, the researchers collected blood from 51 adults between the ages of 21 and 82 who had not been previously infected with COVID-19 and had received two doses of the vaccine between December 2020 and February 2021. The team showed that the antibodies generated in response to the vaccine were effective at neutralizing the original version of SARS-CoV-2 that emerged in 2019, but were not as effective against the delta and omicron variants.

More endorsements for boosters

The antibodies generated differed in function by age. People under 65 carried significantly more antibody activity and functions than those over age 65. Lu said the research suggests boosters are more important in older adults, as well as the need for further vaccine development to prevent infection as new variants emerge.

“Beyond COVID-19, all viruses and bacteria that infect us change over time,” Lu said. “If we understand how antibodies protect us despite these changes, then we can enhance the durability of preventive clinical tools such as vaccines.”

On Wednesday, Sean Christiansen, a policy advisor for the White House Office on COVID Response, urged seniors to get COVID-19 boosters during a press briefing. The Biden administration launched a COVID-19 vaccination campaign last week, which includes $125 million in grants to help senior service organizations get the vaccine into the arms of older adults over the next several weeks.

The COVID-19 pandemic has resulted in nearly 100 million infections and more than 1 million deaths nationwide, according to the Centers for Disease Control and Prevention. People 65 and older have accounted for approximately three-quarters of those deaths.