August 31, 2020 -- The first U.S. case of a confirmed coronavirus reinfection looks to be a patient in Nevada, according to NBC News. The U.S. case comes a few days after the first reinfection in the world was announced in Hong Kong.
The Nevada case is detailed in a new paper published Thursday on an online preprint server. The study has not yet been reviewed by peers.
Reinfection is rare, researchers said, but people should still be cautious.
“If you’ve had it, you can’t necessarily be considered invulnerable to the infection,” Mark Pandori, one of the authors and director of the Nevada State Public Health Laboratory, told NBC.
According to the report, the 25-year-old man from Reno, Nevada, first tested positive for COVID-19 in mid-April after experiencing a sore throat, cough, headache, nausea, and diarrhea. He recovered but got sick again in late May, marking 48 days between two positive tests after two negative tests in between the infections. During the second round, his illness was more severe, and he was hospitalized with pneumonia.
Researchers found that the genetic sequencing of the virus varied, and the patient was infected with slightly different strains of the coronavirus. They aren’t sure why he was reinfected, which could be related to the virus itself or the patient’s immune system.
In Hong Kong, the 33-year-old man with a reinfection also had slightly different strains of the coronavirus, according to STAT. However, he had a milder infection the second time, indicating that an initial immune response might protect the body against subsequent infections to some extent.
Also this week, researchers in Belgium and the Netherlands confirmed reports of coronavirus reinfections, STAT reported. For now, scientists are considering these cases “outliers” and are trying to understand how the immune system responds to the virus. As with many respiratory viruses, including other coronaviruses, antibodies tend to decline over time, which may make people vulnerable again.
“After one recovers from COVID-19, we still do not know how much immunity is built up, how long it may last, or how well antibodies play a role in protection against a reinfection,” Pandori said in a statement from the University of Nevada at Reno.
In reality, infections and immune responses likely vary widely in different people.
“This is a novel disease,” Pandori added. “We still have a steep learning curve ahead and lots of work to do, especially as inconvenient truths arise.”