COVID boosters are ‘more important’ for older adults, study suggests. Here’s why

Esteban Felix/AP

Older adults may benefit more from the latest COVID-19 boosters and future updates to the vaccines, recent research suggests.

These individuals are being disproportionately affected by the virus in the U.S. compared with younger citizens, government data shows. To date, the majority of deaths attributed to COVID-19 — 75% — are of people ages 65 and older, according to data from the Centers for Disease Control and Prevention.

The pandemic has increasingly distinguished itself as “a plague of the elderly,” the Washington Post reports.

A study conducted by researchers at UT Southwestern Medical Center in Dallas, Texas, found protection offered by two doses of a COVID-19 vaccine decreases with age and is “suboptimal” for older adults. The findings were published in late October in the journal Cell Reports.

Because of this, “COVID-19 boosters and updated vaccines are more important for older adults, who are more susceptible to severe illness with the virus” as newer COVID-19 variants emerge, a Nov. 29 UT Southwestern news release on the research states.

The study involved 51 participants, ages 21 to 82, who received two doses of Pfizer’s original vaccine and were never known to be infected with the virus. Researchers analyzed samples of their blood to examine the effectiveness of two Pfizer shots.

The research comes as more than half of the U.S. population, 68.8%, has gotten two vaccine doses, according to the latest CDC data.

Meanwhile, just 12% of people have gotten an updated booster dose that targets two newer versions of the omicron variant, the CDC reports. About 31% of adults ages 65 and older have gotten the new booster.

But why are two doses of Pfizer’s original vaccine less effective for older adults compared with younger people? It comes down to how antibodies function, researchers say.

More on the study

To guard against COVID-19, mRNA vaccines like Pfizer and Moderna’s kickstart the body’s immune response by causing the production of antibodies, according to the CDC. These antibodies protect against getting sick from the virus.

After a COVID-19 infection or vaccination, antibodies to SARS-CoV-2 can be found in the blood, the CDC says.

The UT Southwestern researchers collected blood samples of 51 participants of varying ages after they received two shots of Pfizer’s vaccine between December 2020 and February 2021, according to the study.

The researchers noticed some differences when it came to antibody functions — specifically that antibodies were less effective and active for older participants after they were vaccinated with Pfizer’s original shots, the release says.

“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,” Dr. Lenette Lu, lead study author and an assistant professor of internal medicine and immunology at UT Southwestern, said in a statement.

The differences, when it comes to age, is due to “different sugars attached to the antibodies,” the release explains. “With age, these sugars change and antibody functions diminish.”

The updated COVID-19 booster doses were developed to better protect against the omicron variant, according to the Food and Drug Administration. Each dose includes a piece of the original virus strain, which the original vaccines were made of, and a second component targeting omicron specifically.

Ultimately, because the study shows receiving two doses of an original vaccine is less effective for older individuals, it “underscores the need for boosters and variant-specific vaccines in older adults,” the release states.

In the U.S., nearly 51.5 million adults 65 and older have gotten two vaccine doses, according to the CDC. To compare, slightly more than 17 million of these individuals have gotten an updated booster dose.

Currently, this age group makes up nearly 9 in 10 COVID-19 deaths based on an analysis of the latest CDC data, according to the Washington Post.

“I think about someone’s grandfather — the plays they wouldn’t watch, the games on the football field they wouldn’t see,” Yellowstone County, Montana health officer John Felton, who has been tracking local virus deaths, told the newspaper.

UT Southwestern study authors wrote some limitations of their research included the small sample size and a lack of “ethnicity, race and clinical data.”

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