Covid-19: How long does immunity last in the elderly?
Previous studies had already analyzed the duration of acquired immunity after infection with the coronavirus. But a doubt hung over the elderly, with immunity, as we know, more fragile.
Several studies have already shown that our body preserves the memory of infection with a respiratory virus such as SARS-CoV2 and that it is able to reactivate the production of antibodies if necessary. According to the latest estimates, immunity would be at least eight to ten months.
But what about older people? We wonder about its ability to retain this ability to defend itself over time, because we know that the immune system weakens over the years.
A new study is reassuring. British researchers from the University of London analyzed the SARS-COV2 infection rate of nearly 700 nursing home residents, with an average age of 86, and more than 1,400 nursing home caregivers at the end of 2020. Their results show that patients (such as caregivers, younger than 65 years old) who had Covid-19 saw their risk of a new infection reduced by 85% up to ten months after the illness, compared to those who had never been in contact with the virus.
According to their findings, published in The Lancet Healthy Longevity, natural immunity could last up to ten months, even in this most fragile population. "It is very good news that natural infection protects against re-infection in this way during that period," the scientists said. As this study was conducted before vaccination was established, researchers must now determine whether the immunity provided by vaccines provides the same benefits and whether the arrival of coronavirus variants could lead to a different long-term immune response.