Written By: Longjam Dineshwori | Updated : October 14, 2020 12:07 PM IST
COVID-19 has caused over one million deaths worldwide so far.
Cases of COVID-19 reinfection are being reported from across the world suggesting that exposure to the virus may not guarantee future immunity. In fact, a study published in The Lancet Infectious Diseases journal stated that COVID-19 patients may experience more severe symptoms when they get infected for the second time. There are about 25 known cases of COVID-19 reinfections in the world. According to the latest media report, one of these patients from the Netherlands has died after falling ill with COVID-19 for the second time. The patient, an 89-year-old Dutch-origin woman, is believed to be the first known case of death due to re-infection with coronavirus.
When the woman was infected with coronavirus for the first time, she had developed symptoms such as high fever and a strong cough. She was discharged from the hospital after five days and tested negative in two PCR to which she was subjected after the symptoms disappeared. After two months, she got infected with a different strain of the virus and developed fever, cough, and severe shortness of breath, for which she was readmitted to the hospital, the reports said.
The Dutch patient was also suffering from Waldenstr m's Macroglobulinemia, a rare form of bone marrow cancer, which had apparently weakened her immune system. She was found reinfected with COVID-19 two days after her chemotherapy treatment and died two weeks later.
The study published in The Lancet Infectious Diseases journal also reported the first confirmed case of COVID-19 reinfection in the United States. A 25-year-old Nevada man was infected with two distinct variants of COVID-19 virus within a 48-day time frame while testing negative in between infections. As per the paper, the patient suffered more severe symptoms during the second infection, resulting in hospitalisation with oxygen support. He had no known immune disorders or underlying conditions, stated the scientists, including those from the University of Nevada in the US.
The man tested negative for the virus after testing positive for SARS-CoV-2 in April 2020. Then in June 2020, the patient tested positive for a second time and was hospitalised with severe COVID-19 symptoms, including fever, headache, dizziness, cough, nausea, and diarrhea. The patient has recovered from the second infection and discharged from the hospital, the study noted.
There are several hypotheses on the severity of the second infection. One theory is that COVID-19 patients might have encountered a very high dose of the virus which caused a more acute reaction the second time.
According to the Lancet study, the US patient may also have come in contact with a more virulent variant of the virus.
Another plausible reason, according to the researchers, could be the mechanism of antibody dependent enhancement. Some protective proteins produced by the immune system during the first encounter with the virus could make a subsequent infection worse, they explained, adding that this mechanism was also seen with the 2002-03 SARS pandemic virus, as well as dengue fever.
While there are still many unknowns about SARS-CoV-2 infections and the immune system's response, these findings indicate that a previous infection may not guarantee protection against future infection, noted Mark Pandori, lead author of the study from the University of Nevada.
Therefore, all individuals whether previously diagnosed or not should take identical precautions including social distancing, wearing face masks, and handwashing to prevent infection with SARS-CoV-2, he added.
With inputs from agencies
