Covid-19 Vaccine Immune Response Linked To Age

OREGON CITY, Ore. — A new laboratory study from Oregon Health and Science University suggests that older people have fewer antibodies against the novel coronavirus.

The study titled “Age-Dependent Neutralization of SARS-CoV-2 and P.1 Variant by Vaccine Immune Serum Samples” was published in the “Journal of the American Medical Association.”

Antibodies are blood proteins that are made by the immune system to protect against infection. They are vital players in protection against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

“Our older populations are potentially more susceptible to the variants even if they are vaccinated,” Fikadu Tafesse, Ph.D., senior author, and assistant professor of molecular microbiology and immunology in the School of Medicine of the Oregon Health and Science University, said.

Tafesse and colleagues emphasized that even though they measured diminished antibody response in older people, the vaccine still appeared to be effective enough to prevent infection and severe illness in most people of all ages.

“The good news is that our vaccines are really strong,” Tafesse said.

However, with vaccine uptake slowing in Oregon and across the United States, researchers say their findings underscore the importance of promoting vaccinations in local communities.

Vaccinations reduce the spread of the virus and new and potentially more transmissible variants, especially for older people who appear to be more susceptible to breakthrough infections.

“The more people get vaccinated, the less the virus circulates,” Tafesse said.

“Older people aren’t entirely safe just because they’re vaccinated; the people around them really need to be vaccinated as well. At the end of the day, this study really means that everybody needs to be vaccinated to protect the community (sic).”

Researchers measured the immune response in the blood of 50 people two weeks after their second dose of the Pfizer vaccine against Covid-19. They grouped participants into age groups and then exposed their blood serum in test tubes to the original “wild-type” SARS-CoV-2 virus and the P.1 variant (also known as gamma) that originated in Brazil.

The youngest group — all in their 20s — had a nearly seven-fold increase in antibody response than the oldest group of people between 70 and 82 years of age. The laboratory results reflected a clear linear progression from youngest to oldest: The younger a participant, the more robust the antibody response.

“Older people might be more susceptible to variants than younger individuals,” Tafesse said.

Marcel Curlin, Doctor of Medicine (MD), co-author and associate professor of medicine (infectious diseases) in the School of Medicine of the Oregon Health and Science University, says that the findings highlight the importance of vaccinating older people as well as others who may be more vulnerable to Covid-19.

“The vaccine still produces strong immune responses compared with natural infection in most older individuals, even if they are lower than their younger counterparts,” Curlin said.

“Vaccination in this group may make the difference between serious and mild disease, and likely reduces the chances of transmitting SARS-CoV-2 to another person.”

(With inputs from ANI)

(Edited by Amrita Das and Nikita Nikhil)