Scientists say Hong Kong man got coronavirus a second time

University of Hong Kong scientists claim to have first evidence of someone being reinfected with virus that causes COVID-19. Genetic tests revealed that a 33-year-old man returning to Hong Kong from a trip to Spain in mid-August h a different strain of coronavirus than one he'd previously been infected within March, said Dr Kelvin Kai-Wang To, microbiologist who led work. man h mild symptoms first time and ne second time; his more recent infection was detected through screening and testing at Hong Kong airport.

“It shows that some people do t have lifelong immunity” to virus if y've alrey h it, To said.

“We don't kw how many people can get reinfected. re are probably more out re.”

paper has been accepted by journal Clinical Infectious Diseases but t yet published, and some independent experts urged caution until full results are available. Wher people who have h COVID-19 are immune to new infections and for how long are key questions that have implications for vaccine development and decisions about returning to work, school and social activities.

Even if someone can be infected a second time, it's t kwn if y have some protection against serious illness, because immune system generally remembers how to make antibodies against a virus it's seen before. It's t clear how different a virus needs to be to trigger illness, but new work suggests that “COVID patients should t be complacent about prevention measures” and should continue social distancing, wearing masks and or ways to reduce infection, To said. Two experts with with role in work agreed.

“We've always kwn reinfection was a possibility and I think this is highly suggestive” that it occurred in this case, said Dr Jesse Goodman, a former US Food and Drug ministration chief scientist w at Georgetown University.

“If re is a reinfection, it suggests possibility re was residual immunity ... that helped protect patient” from getting sick again, Goodman said.

However, “if immunity wanes from natural infection, it could be a challenge for vaccines” and may mean booster shots are needed, he ded. Julie Fischer, a microbiologist at CRDF Global, a nprofit health group in Arlington, Virginia, said study gives convincing evidence that reinfection can happen.

“ real question is what this means for severity of disease” if that occurs, and wher such people can infect ors, she said.

One expert saw report as good news. Dr Paul Offit, a vaccine expert at Children's Hospital of Philelphia, said it's encouraging reported reinfection was without symptoms.

“That's a win as far as I'm concerned” because it suggests a first infection may protect a person from moderate to severe disease second time around, he said in an interview streamed by Journal of American Medical Association.

A mid-May survey by doctors' information-sharing site Sermo found that 13% of 4,173 doctors responding believed that y h treated one or more patients who were reinfected. Among respondents, 7% of those in US and 16% in or countries thought y'd seen such a case. However, health officials have also wondered wher people who tested positive long after ir initial illness were simply showing signs of t completely clearing virus rar than being infected anew.