COVID-19 vaccine effectiveness declines with age, UTSW research shows: Newsroom

The UTSW researchers’ findings suggest that COVID-19 boosters and catch-up vaccinations are most important for older adults, who are more susceptible to severe illness from the virus. Photo Credit: Getty Images

DALLAS – November 29, 2022 – The Pfizer-BioNTech COVID-19 vaccine limits transmission, hospitalization and death from COVID-19 even among patients infected with variants of the virus, but the effectiveness of the antibodies it generates decreases as the patients get old. according to a study conducted by researchers at UT Southwestern.

Lenette Lu, MD, Ph.D.

“The fact that these antibody functions decline with age is one reason older people remain more susceptible to severe illness with COVID-19 and highlights the need to develop different approaches for the elderly and vulnerable.” said Lenette Lu, MD, Ph. D., Assistant Professor of Internal Medicine and Immunology in the Division of Infectious Diseases and Geographic Medicine, and lead author of the paper published in cell reports.

The vaccine, approved by the US Food and Drug Administration in August 2021, contains a fragment of mRNA encoding the SARS-CoV-2 spike protein, which the virus uses to infect human cells. Initial studies of the vaccine focused on how it led to the generation of antibodies that could prevent SARS-CoV-2 from entering cells, neutralizing the virus before it can cause disease.

The emergence of new variants, including Delta and Omicron, made the vaccine less effective at neutralizing SARS-CoV-2 and resulted in higher infection rates. However, vaccinated people, even when infected with COVID-19, continued to be protected against severe disease and death.

To understand how vaccines protect people without completely neutralizing the virus, blood samples from 51 adults, ranging in age from 21 to 82 years, who had not previously been infected with COVID-19 and who received two doses, were analyzed. of the Pfizer-BioNTech vaccine each. between December 2020 and February 2021. From the samples, the researchers isolated specific antibodies to the SARS-CoV-2 spike protein.

The team showed that the antibodies generated in response to the vaccine were effective in neutralizing the original version of SARS-CoV-2 that emerged in 2019 but, as expected, they were not as effective against the Delta and Omicron variants. In addition, the researchers found that these antibodies led to the activation of immune cells that can carry out a variety of antiviral effector functions after infection.

“In other words, even if an antibody is less able to prevent infection with variants of a virus, it can still block the development of symptoms, the severity of the disease, and the spread from person to person,” said Dr. Lu.

These antibody activities and functions differed by age, with people younger than 65 having significantly more activities and functions compared to people older than 65. Dr. Lu’s team found that these observations could be attributed to different sugars attached to the antibodies. With age, these sugars change and the functions of the antibodies diminish.

The data suggests that boosters and catch-ups are most important for older adults. Additionally, as new variants of SARS-CoV-2 emerge, it is important to better understand how to make vaccines that are effective in preventing disease as well as infection.

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

Other UTSW researchers who contributed to this study include Pei Lu, Ye Jin Kang, Micah Thornton, Chanhee Park, and Daehwan Kim.

This study was supported by grants from the MJ Murdock Charitable Trust, Oregon Health & Science University (1018784), OHSU Foundation, National Institutes of Health (R011R01AI141549-01A1, R01AI145835, T32HL083808), Burroughs Wellcome Fund UT Southwestern Training Resident Doctors as Innovators in Science, and the Disease Oriented Scholars Award from the Department of Internal Medicine and Disease at UT Southwestern.

About UT Southwestern Medical Center

UT Southwestern, one of the nation’s leading academic medical centers, integrates pioneering biomedical research with exceptional education and clinical care. The institution’s faculty has received six Nobel Prizes and includes 24 members of the National Academy of Sciences, 18 members of the National Academy of Medicine, and 14 Howard Hughes Medical Institute Investigators. The full-time faculty of more than 2,900 is responsible for innovative medical advances and is committed to rapidly translating science-driven research into new clinical treatments. UT Southwestern physicians provide care in more than 80 specialties to more than 100,000 hospitalized patients, more than 360,000 emergency room cases and oversee nearly 4 million outpatient visits annually.


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