Assessment of protection against reinfection with SARS-CoV-2 among 4 million PCR-tested individuals in Denmark in 2020: a population-level observational study
Analysis (n >10m test results) found natural infection with SARS-CoV-2 led to observed protection against reinfection estimated to be ~ 80% after 6 mths but observed low natural immunity in age≥ 65yrs underlines need to vaccinate previously infected, particularly this age group.
Source:
The Lancet
SPS commentary:
According to a commentary, the quality, quantity, and durability of protective immunity elicited by natural infection with SARS-CoV-2 are poor relative to the much higher levels of virus-neutralising antibodies and T cells induced by the vaccines currently being administered globally. In addition, emergence of variants of SARS-CoV-2 with variable escape from natural and vaccine-induced immunity complicates matters further, and might shift immunity below a protective margin, prompting the need for updated vaccines. It notes that interestingly, vaccine responses even after single dose are substantially enhanced in individuals with a history of infection with SARS-CoV-2. It suggests these data are all confirmation, if it were needed, that for SARS-CoV-2 the hope of protective immunity through natural infections might not be within reach, and a global vaccination programme with high efficacy vaccines is the enduring solution.