Most people infected with the corona virus are protected from re-infection for at least six months. According to a new study Published by Danish researchers in the medical journal Lancet. However, that immunity decreases significantly with age.
This study underscores the importance of vaccinating older people, but also individuals who have previously been exposed to the virus.
The researchers analyzed data from Denmark National Testing and Monitoring Program, Under which nearly 70 percent of the population was tested for the corona virus last year. They found that natural infections reduce the chance of getting the virus back to 80 percent in people under the age of 65 – and there is no evidence that that protection is weakened over a six-month period.
Of those over 65, the first bout with the virus provided just 47 percent protection against re-infection. The study did not examine the possibility of re-infection from new virus strains, including those first identified in Brazil, the UK and South Africa.
A Commentary published with the study, Two British immunologists at Imperial College London called the results “relevant” and stressed the need to increase vaccination programs.
“The quality, quantity and longevity of immunity expressed by natural infection with SARS-CoV-2 are currently poor compared to the high levels of virus-neutralizing antibodies and T cells induced by globally administered vaccines,” wrote Rosemary Boyden and Danny Altman. “The hope of immunity to protection against natural infections should not be within our borders, and a global vaccination program with highly effective vaccines is the lasting solution.”