SYDNEY, March 30 (Xinhua) -- Australian Nobel laureate immunologist Peter Doherty said it is highly improbable that people who have recovered from COVID-19 will be infected again, and even if it turns out to be the case, the secondary infection would be mild or inapparent.
In a written interview with Xinhua, Doherty said the PCR test used to detect virus is very sensitive. The more likely explanation to why there were reports saying people tested positive after being released from hospital is that for someone who has recovered clinically, the virus has not been fully cleared, even though they may have had a prior negative test.
"What would support the idea of reinfection is if the lab found significant gene sequence difference for the early and late isolates," he said.
"Of course, we have only known about this virus for a very short time, and it's always possible that it may have some nasty surprises for us."
Doherty shared the Nobel Prize in Physiology or Medicine in 1996 with Swiss scientist Rolf Zinkernagel for their discoveries concerning the specificity of the cell-mediated immune defence and the biological role of the major histocompatibility complex. The leading Peter Doherty Institute for Infection and Immunity, which is named in honor of him, is also engaged in the research of the virus and the development of the vaccine.
"Candidate vaccines are going into lab animals or humans already, and there will be many to follow. The vaccine we're working with is a comparable SARS-CoV-2 product generated using a novel 'protein clamp' technology. This originates from Paul Young's group at the University of Queensland, and is being grown up by the CSIRO (the Commonwealth Scientific and Industrial Research Organization) who will also do the advanced animal experiments at their high security lab in Geelong and we are helping with the lab testing. Very early results look promising," Doherty said.
"The long lead times suggested for these vaccines reflect the need for rigorous efficacy and safety testing. Maybe, if everything goes very well for at least one of them, we may see a product out there and into people's arms sooner rather than later," he noted.
As for how to boost the immunity, he said, without a fully functioning immune system people will die from the COVID-19. However, nothing much people can do to boost the basic immunity in the absence of a vaccine. Eating a balanced diet may help. Most of the products that claim to "boost immunity" have, when tested, failed to show that they are of any benefit.
As for the claim that kids seem to be less likely contracted with the virus, Doherty said it could be that kids have less receptors for the virus on their cells, or they make very good immune responses. "We don't know why, but over time we will find out."
