LTC residents with prior COVID-19 infection may have big immune advantage, study finds – Clinical Daily News

Nursing home residents who have weathered a prior COVID-19 infection are more likely to show robust signs of immunity to SARS-CoV-2 six months after vaccination, a study across five facilities has found. But age and frailty may play a role in weakening this vaccine response, researchers say.

Participants, recruited from long-term care facilities in Dublin, Ireland, were assessed for the presence of anti-spike antibodies (markers of coronavirus immunity) in their blood before receiving the Pfizer-BioNTech COVID-19 vaccine. These antibody titers were also measured at five weeks and six months post-vaccination. Just under half of the 86 participants (45%) had evidence of previous SARS-CoV-2 infection.

All participants had a significant antibody response to vaccination at five weeks and a significant decline in this response by six months, reported Sean P. Kennelly, Ph.D., of the Tallaght University Hospital and St. James’s Hospital Campus, each in Dublin. 

In older residents, a history of SARS-CoV-2 infection was the strongest predictor that anti-spike antibody titers would be found in the blood at six months, Kennelly and colleagues found. The presence of these antibody measures were also tied to COVID-19 immune response in lab tests, the researchers noted. 

In contrast, age and frailty were independently associated with lower anti-spike antibody measures at six months. 

Taken together, the findings support booster programs, particularly for residents who have not been infected, the researchers said. Additional vaccine doses “could be beneficial if they are to boost antibody responses in this vulnerable population, particularly in those with no history of SARS-CoV-2 infection,” they concluded.

Full findings were published in JAMDA.