Houston: COVID-19 patients infected with the novel coronavirus for a second time might experience more severe symptoms. This is according to a study which is the first to confirm a case of re-infection with the virus in the US. The study has been published in the journal ‘Lancet Infectious Diseases’. It has found evidence that an individual with no known immune disorders or underlying conditions was infected with the SARS-CoV-2 virus in two separate occurrences.
The scientists, including those from the University of Nevada, said the patient, a 25-year old male, was infected with two distinct SARS-CoV-2 variants within a 48-day time frame. In between he had tested negative for COVID infections. The study noted that the patient’s second infection was more severe. It resulted in hospitalisation with oxygen support. The development indicated previous exposure to COVID-19 may not translate to guaranteed total immunity.
The patient tested negative for the virus after testing positive for SARS-CoV-2 in April 2020. Then in June 2020, after experiencing severe COVID-19 symptoms, including fever, headache, dizziness and diarrhea, the patient was hospitalized. He then tested positive for a second time, said researchers.
The patient has since been discharged from the hospital. He has recovered from the second infection, the study noted.
While further research into re-infections is required, the scientists believe all individuals – whether previously diagnosed or not – should take identical precautions to prevent infection with SARS-CoV-2.
“There are still many unknowns about SARS-CoV-2 infections and the immune system’s response. However, our findings signal that a previous SARS-CoV-2 infection may not necessarily protect against future infection,” said Mark Pandori. He is the lead author of the study from the University of Nevada.
“It is important to note this is a singular finding and does not provide generalisability of this phenomenon. The possibility of re-infections could have significant implications for understanding COVID-19 immunity, especially in the absence of an effective vaccine. It also strongly suggests that individuals who have tested positive for SARS-CoV-2 should continue to take serious precautions. They include social distancing, wearing face masks, and handwashing,” Pandori added.
According to the scientists, at least four other re-infection cases have been confirmed globally in Belgium, the Netherlands, Hong Kong, and Ecuador.
“We need more research to understand how long immunity may last for people exposed to SARS-CoV-2. Also time is required to find out why some of these second infections, while rare are more severe,” Pandori said.
“So far, we’ve only seen a handful of re-infection cases, but that doesn’t mean there aren’t more. Right now, we can only speculate about the cause of re-infection,” he added.
The study noted several hypotheses that may explain the severity of the second infection, including the possibility the patient subsequently encountered a very high dose of the virus which caused a more acute reaction the second time. According to the researchers, the patient may also have come in contact with a more virulent variant of the virus.