Cause for alarm?
Despite evidence that reinfection is relatively rare, “many will find the data reported by Hansen and colleagues about protection through natural infection relatively alarming,” Dr. Boyton and Dr. Altmann wrote in their commentary. The 80% protection rate from reinfection in general and the 47% rate among people aged 65 and older “are more concerning figures than offered by previous studies.”
Vaccines appear to provide better quality, quantity, and durability of protection against repeated infection – measured in terms of neutralizing antibodies and T cells – compared with previous infection with SARS-CoV-2, Dr. Boyton and Dr. Altmann wrote.
More research needed
The duration of natural protection against reinfection remains an unanswered question, the researchers noted, “because too little time has elapsed since the beginning of the pandemic.”
Future prospective and longitudinal cohort studies coupled with molecular surveillance are needed to characterize antibody titers and waning of protection against repeat infections, the authors noted. Furthermore, more answers are needed regarding how some virus variants might contribute to reinfection risk.
No funding for the study has been reported. Dr. Michlmayr, Dr. Hirschwerk, Dr. Wherry, Dr. Boyton, and Dr. Altmann have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.