A 25-year-old man from Nevada and a 42-year-old man in Virginia experienced second bouts of COVID-19 about 2 months after they tested positive the first time. Gene tests show both men had two slightly different strains of the virus, suggesting that they caught the infection twice.
Researchers say these are the first documented cases of COVID-19 reinfection in the U.S. About two dozen other cases of COVID-19 reinfection have been reported around the globe, from Hong Kong, Belgium, the Netherlands, India, and Ecuador. A third U.S. case, in a 60-year-old in Washington, has been reported but hasn't yet been peer reviewed.
Until now, immunologists haven't been too concerned about these reinfections because most second infections have been milder than the first, indicating that the immune system is doing its job and fighting off the virus when it is recognized a second time.
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