Confirmed COVID reinfection in the US raises questions about immunity to...

The first confirmed US case of coronavirus reinfection has been reported by researchers.

A 25-year-old man with no known immune or underlying diseases was infected twice with COVID-19, according to a study published in the Lancet Infectious Diseases Journal.

While the authors said more research was needed, they added that prior exposure to the virus may not guarantee complete immunity.

According to researchers, this is the fifth confirmation of re-infection in the world. At least four other cases have been confirmed in Belgium, the Netherlands, Hong Kong and Ecuador.

The patient, who lives in Nevada, had a second infection that was more severe than the first and resulted in an oxygen-assisted hospitalization.

Researchers at the Nevada State Public Health Laboratory and the University of Nevada said he tested positive for the virus in April this year and later tested negative twice.

When he experienced COVID-19 symptoms such as fever, headache, dizziness, cough, nausea, and diarrhea in June, he was hospitalized and tested positive a second time.

Genetic sequencing of the virus showed that it was infected twice with different Sars-CoV-2 strains, according to researchers.

Lead author Mark Pandori of the Nevada State Public Health Laboratory said it was important to note that the individual finding should not be generalized.

“While more research is needed, the possibility of reinfection could have a significant impact on our understanding of COVID-19 immunity, especially in the absence of an effective vaccine,” he said.

“It is also highly recommended that people who test positive for Sars-CoV-2 should continue to take serious precautions regarding the virus, including social distancing, wearing face masks, and hand washing.”

He added that more research is needed to understand how long immunity can last for those exposed to the virus and why secondary infections, although rare, are more serious.

The authors made several explanations as to the severity of the second infection, including the fact that if the patient was reinfected, they encountered a very high dose of the virus.

According to researchers, he may also have come into contact with a more virulent version of the virus.

They added that confirmed reinfections have occurred in patients who have shown symptoms, meaning that reinfections can occur in patients who are asymptomatic and therefore go undetected.

Pandori said there was a lack of “comprehensive genomic sequencing of positive COVID-19 cases” worldwide, as well as a lack of screening and testing, which limited the researchers.