A Nevada man has been reinfected with the coronavirus, the first documented case in the United States.

His second infection was worse than the first, USA Today reports: “He has recovered, but his case raises questions about how long people are protected after being infected with the coronavirus that causes the disease, and potentially how protective a vaccine might be. … It's too soon to know whether the man from Washoe County, Nevada, who had no known health problems other than his double infection, was highly unusual or if many people could easily get infected more than once with SARS-CoV-2, [Dr. William] Schaffner said.”

There have been 22 documented cases of COVID reinfection globally.

In related news, a Johnson & Johnson COVID vaccine trial has been halted due to an unexplained illness in one of the participants.

Said the company: “We must respect this participant's privacy. We're also learning more about this participant's illness, and it's important to have all the facts before we share additional information.”

STAT News reports: “J&J emphasized that so-called adverse events — illnesses, accidents, and other bad medical outcomes — are an expected part of a clinical study, and also emphasized the difference between a study pause and a clinical hold, which is a formal regulatory action that can last much longer. The vaccine study is not currently under a clinical hold. J&J said that while it normally communicates clinical holds to the public, it does not usually inform the public of study pauses.”