First Confirmed US Case of Coronavirus Reinfection Raises Questions Over Efficacy of COVID-19 Vaccines

Genomic sequencing of a US COVID-19 patient’s virus samples performed in two different months has displayed significant genetic discordance between the two cases, implying that the patient was infected twice.

Scientists at the Reno School of Medicine (UNR Med) of the University of Nevada (Reno, NV, USA), led by its Nevada State Public Health Laboratory (NSPHL) are studying a likely case of COVID-19 reinfection in the US. Forty-eight days after testing positive for SARS-CoV-2 in April 2020 and after testing negative consecutively twice, the patient tested positive again, in June. The patient had tested negative on two separate occasions in the interim. The genomes of the patient’s virus samples were sequenced in April and June, displaying significant genetic discordance between the two cases, implying the patient was infected twice.

“We examined the genomic material of the viruses and samples to investigate this,” said Mark Pandori, Ph.D., director, NSPHL. “It is just one finding, but it shows that a person can possibly become infected with SARS-CoV-2 a second time.”

There are currently many more unknowns than knowns about immune responses to COVID-19. “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,” added Pandori.

According to Pandori and the NSPHL-led research team, reinfection cases are a potential warning sign that it is possible to catch COVID-19 more than once, and with unpredictable severity. “If reinfection is possible on such a short timeline, there may be implications for the efficacy of vaccines developed to fight the disease. It may also have implications for herd immunity,” said Pandori.

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