U.S. researchers have confirmed the country’s first case of COVID-19 reinfection, indicating that exposure to the virus may not translate to total immunity.
The first study to confirm a case of coronavirus reinfection in the U.S. found evidence that an individual with no known immune disorders or underlying health conditions was infected with SARS-CoV-2, the virus that causes COVID-19, in two separate instances.
According to a new case study, published Monday in The Lancet, the 25-year-old Nevada man was infected by two different SARS-CoV-2 variants within a 48-day timeframe, while testing negative between each infection.
Researchers reported that the patient’s second infection was more severe, resulting in hospitalization with oxygen support.
Dr. Mark Pandori, director of the Nevada State Public Health Laboratory, said the findings indicate that previous exposure to COVID-19 does not mean an individual is guaranteed total immunity from the disease. However, he says more research is needed.
“There are still many unknowns about SARS-CoV-2 infections and the immune system’s response, but our findings signal that a previous SARS-CoV-2 infection may not necessarily protect against future infection,” Pandori said in the study.
The patient was first diagnosed with COVID-19 in April, according to the study. He got better around April 27, and tested negative for the virus twice afterwards.
In June after experiencing severe COVID-19 symptoms including fever, headache, dizziness, cough, nausea and diarrhea, the patient was hospitalized and tested positive for the virus a second time.
The genomes of the patient’s virus samples were sequenced in April and June, displaying “significant genetic differences” between the two cases. Researchers say this implies that the patient was infected twice by two distinct SARS-CoV-2 infections.
The study says the patient has since been discharged from the hospital and has recovered from the second infection.
Pandori noted that all individuals, whether previously diagnosed with the novel coronavirus or not, should continue to take the necessary safety precautions to prevent infection such as physical distancing, wearing a face mask and handwashing.
“It is important to note this is a singular finding and does not provide generalizability of this phenomenon. While more research is needed, the possibility of reinfections could have significant implications for our understanding of COVID-19 immunity, especially in the absence of an effective vaccine,” Pandori said.
The new case marks the fifth confirmation of COVID-19 reinfection globally.