A Nevada man is the first person in the U.S. confirmed to be infected with the coronavirus for a second time, with scientists saying there is evidence to show he wasn't having a relapse of the original infection. The case study reinforces that people who have contracted COVID-19 once may not necessarily be immune.
The study, published in The Lancet, says the 25-year-old man tested positive at a community testing event on April 18 after showing several symptoms associated with COVID-19. The patient had no history of clinically significant underlying conditions, the study said. He recovered nine days later.
The patient felt severe symptoms again on May 31 and went to urgent care. Five days later, he followed up with his doctor and then went to the emergency room. He tested positive on June 5 and again on June 6. He recovered from his second bout.
"The second infection was symptomatically more severe than the first," the study's findings read. It also found the genetic discordance in the first and second cases was too great for it to be a recurrence of the original infection. The man had also tested negative twice between the infections -- on May 9 and May 26.
"Thus, previous exposure to SARS-CoV-2 might not guarantee total immunity in all cases," the study authors wrote. They said anyone who has previously been infected with COVID-19 should still take precautions to avoid being infected again.
The authors say the implications of reinfection could affect the development and application of a vaccine.
This is the first U.S. case of reinfection and the fifth worldwide. In one of those cases, in Ecuador, the patient also got sicker the second time. The other confirmed reinfection cases are from Hong Kong, the Netherlands and Belgium.