How much protection against future infections does prior infection with SARS-CoV-2 infection provide? This is an important question for advising individual patients, as well as for projecting future outbreaks of SARS-CoV-2.
In this issue of JAMA Internal Medicine, Vitale and colleagues1 use the results of diagnostic reverse-transcriptase–polymerase chain reaction tests in Lombardy, Italy, to compare the incidence of SARS-CoV-2 infection among persons with prior SARS-CoV-2 infection with persons who tested negative for the virus.