Reacting to this, the World Health Organization says this may provide important information for scientists studying immunity and developing a vaccine.
Margaret Harris, spokeswoman for the WHO said on Tuesday that news of a Hong Kong man getting infected twice with the Covid, offers the first proof that reinfection with the virus that causes COVID-19 is possible. She acknowledged the first “clear documentation” , but also advised caution that the number of such cases in all probability is going to be very low.
She noted that the case in Hong Kong was just one in 23 million lab-confirmed coronavirus infections worldwide so far.
“We will probably see other documented cases, but it seems to be not a regular event,” she told reporters.
“It is not the same as the immune protection that a vaccine provides,” she added, noting that part of the development of vaccines involves ensuring that they confer immunity.
“With the vaccine, you ideally want stronger immunity. That’s one of the things you’re looking for when you’re studying what sort of immunity your candidate vaccine stimulates,” Harris said.
According to Megan Culler Freeman, a virologist with expertise in coronaviruses and enteroviruses, only way to really answer the question of reinfection is by sequencing the viral genome at the time of each infection and looking for differences in the genetic code.
In an article published in the Conversation, she has addressed some question raised by the news of a 33-year old man having a second SARS-CoV-2 infection.
- Immunity to endemic coronaviruses is very short-lived. There is a high chance of reinfections caused by the same reason.
- Reinfection with COVID-19 should not be considered as a big surprise, says she.
- Multiple mechanisms are responsible for producing immunity against any disease. These complex mechanisms have the generation of antibodies.
- Studies are still going on around the world to learn about immunity to SARS-CoV-2, that causes COVID-19.
So, can’t say for sure, based on this one case, whether reinfection will be a cause for broad concern, she says.
Paper, written by the University of Hong Kong scientists, on Covid-19 reinfection, has been accepted by the journal Clinical Infectious Diseases but not yet published, and some independent experts urged caution until full results are available.
Mark Slifka, a viral immunologist at Oregon Health & Science University, does not seem to agree with this paper. His takeaway from the paper is the opposite of what the authors claim.
“Even though [the patient] got infected with a very different strain that’s distinct from the first time around, they were protected from disease,” he says. “That is good news.”