Almost two months after testing positive for the novel coronavirus for the first time, the 89-year-old woman began receiving chemotherapy treatment for Waldenström's macroglobulinemia, a malignant disorder of the bone marrow and lymphatic tissues.
The elderly patient was the subject of an academic paper recently published by the Oxford University Press which said that the woman died 59 days after the start of her first bout of the virus.
Forty-eight days after he tested positive for the infection for the first time, on June 5, the man contracted coronavirus again, with this time the symptoms being "severe".
She was discharged five days later and her symptoms "subsided entirely". She died two weeks later.
The woman was not tested between infections, so researchers have no confirmed negative tests.
Scientists sequenced the genomes of the patient's virus samples and found significant differences, suggesting the man was infected by two distinct versions of the coronavirus. Based on this they concluded that "it is likely that the second episode was a reinfection rather than prolonged shedding". "Thus, previous exposure to SARS-CoV-2 might not guarantee total immunity in all cases", the study's authors said.
The Nevada case is the fifth confirmation of COVID-19 reinfection globally.
In The Lancet Infectious Diseases, researchers said: "Reinfection with SARS-CoV-2 has been reported in at least four individuals worldwide".
"The implications of reinfections could be relevant for vaccine development and application".
In the U.S., a 25-year-old from Reno (Nevada) reportedly contracted the virus in April after showing mild symptoms, then got sick again in late May with a more serious bout. From a public health perspective, all individuals-whether previously diagnosed or not-must take identical precautions to prevent infection with SARS-CoV-2.
He became re-infected 4.5 months after contracting the virus initially, and showing showed no symptoms the second time round.
Although reinfection has not been common, the case has raised new questions about COVID-19 immunity: Does a recovered patient become immune to the virus?