‘Reinfected patients may have worse symptoms’
PARIS/ LONDON: Covid- 19 patients may experience more severe symptoms the second time they are infected, according to research released on Tuesday, confirming it is possible to catch the potentially deadly disease more than once.
A study published in The Lancet Infectious Diseases journal charts the first confirmed case of Covid-19 reinfection in the US and indicates that exposure to the virus may not guarantee future immunity.
The patient, a 25-year-old Nevada man, was infected with two distinct variants of SarsCoV-2 within a 48-day time frame. The second infection was more severe than the first, resulting in the patient being hospitalised with oxygen support.
The paper noted four other cases of reinfection confirmed globally, with one patient each in Belgium, the Netherlands, Hong Kong and Ecuador.
“The possibility of reinfections could have significant implications for our understanding of Covid-19 immunity,” said Mark Pandori, for the Nevada State Public Health Laboratory and lead study author. “We need more research to understand how long immunity may last for people exposed to Sars-CoV-2 and why some of these second infections, while rare, are presenting as more severe.”
The authors said the US patient could have been exposed to a high dose of the virus the second time around, triggering a more acute reaction. Alternatively, it may have been a more virulent strain of the virus.
Another hypothesis is a mechanism known as antibody dependent enhancement - that is, when antibodies make subsequent infections worse, such as with dengue fever.
Britain, meanwhile, is moving closer to carrying out studies that would intentionally infect healthy people with the coronavirus to help researchers in their quest for Covid-19 vaccines, and thousands of volunteers are ready to go. Open Orphan, parent of human challenge trial specialist hVivo, has said it’s in talks with potential customers including the UK to conduct tests of Covid shots.
China launched a drive to test all residents of Qingdao after cases were detected on Sunday. More than 4mn samples had been collected and 1.9mn results returned as of Tuesday afternoon, Qingdao authorities said.