The 58-year-old patient with a history of asthma tested positive for the virus in September. He had a fever and difficulty breathing, but recovered in several days and tested negative twice the following month, scientists wrote in a paper recently published in Clinical Infectious Diseases.
More than 100 days later, he developed symptoms and tested positive yet again. Sequencing revealed several mutations characteristic of the B.1.351 variant, altering the surface spike proteins. A week later, the man’s condition worsened and he required ventilation.
Scientists said the strain behind the first positive test wasn’t available for sequencing, though they noted the case occurred before the strain emerged in South Africa and months before it was detected in France.
"This is, to our knowledge, the first description of reinfection with the South African SARS-CoV-2 VOC 501Y.V2 causing severe COVID-19, four months after a first mild infection," study authors wrote.
The strain has sparked significant concern because it has increased transmissibility and showed to diminish vaccines’ efficacy, with several companies now planning for variant booster shots to raise protection against the strains.
The team of French researchers said "reinfections have been described but remain rare albeit probably underestimated," and due to undersurveillance, it is difficult to confirm whether the researchers found the first true case of reinfection with the variant, per the Washington Post.
This strain has spread worldwide since late last year, and there are 17 reported cases across eight U.S. states, according to the Centers for Disease Control and Prevention (CDC). Study authors say it is still "controversial" whether prior infection can protect against reinfections.
"Our case illustrates that the 501Y.V2 SARS-CoV-2 variant can also be responsible for severe reinfections after a first mild infection with non-VOC SARS-CoV-2," reads the study. "Further investigation is urgently needed to assess cross immunity against VOC 501Y.V2, and to monitor vaccine effectiveness against new variants."