In a study of more than 80 men and women from Baltimore, Maryland, Johns Hopkins researchers added to the evidence that COVID-19 booster shots are essential for maintaining long-term immunity against infection, especially in the elderly.
The results of the study, published on August 15 in Clinical infectious diseasesdirectly support CDC vaccination guidelines recommending COVID-19 boosters, investigators say.
A previous study documented a significant decline in the protective antibody response in all vaccinees six months after an initial two-dose series of mRNA vaccines, particularly in older adults whose immune systems weaken with age and responds less effectively to viral and bacterial infections. These earlier studies also showed a greater decline in immune response in males compared to females in adults over 74 years of age.
During clinical trials of COVID-19 mRNA vaccines prior to U.S. Food and Drug Administration approval, antibody response was found to be elevated in the elderly, conferring robust protection against infection and hospitalization. However, continued monitoring of these people showed a decline in antibodies after six months.
For the new study, Johns Hopkins Medicine investigators tested COVID-19 antibody levels in blood samples from more than 80 adults aged 75 to 98 who had received two initial doses of mRNA vaccines made by Pfizer. or Moderna and no known history of COVID infection. .
As a comparison group, the researchers also tested the blood of 84 adults under the age of 75 with the same vaccination and infection history.
These initial samples showed that the older adults overall had three to eight times lower antibody levels than the younger group, but the older men in particular had one to three times lower antibody levels than the younger group. their female counterparts.
However, when blood samples were taken again and tested 14 to 30 days after a booster shot, the elderly people’s antibody levels matched those of the younger group. A third dose also eliminated disparities between men and women within the same age group.
The data supports the CDC guidelines for COVID-19 vaccination and asserts that the vaccine is initially capable of mounting a good antibody response.
Sean Leng, MD, Ph.D., Professor of Medicine, Johns Hopkins University School of Medicine
Dr. Sean Leng specializes in geriatric medicine at Johns Hopkins University School of Medicine.
But, he adds, older people should be especially encouraged to get vaccinated and vaccinated to protect them from breakthrough infections as immunity wanes.
Leng says the study also underscores the importance of continued research into factors that can affect immunity, such as type of vaccine, age, gender and frailty.
Shapiro, JR. et al. (2022) Association of frailty, age, and biological sex with severe acute respiratory syndrome coronavirus 2 messenger RNA vaccine-induced immunity in the elderly. Clinical infectious diseases. doi.org/10.1093/cid/ciac397.