Recovered Covid-19 patients likely to have some immunity, says Nipah virus scientist

KUALA LUMPUR: Covid-19 patients are likely to have some level of immunity to re-infection based on past experiences with the related Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) coronaviruses, says a Universiti Malaya research consultant.

Academician Emeritus Professor Datuk Dr Lam Sai Kit, who was central to the discovery of the Nipah virus, said following recovery from SARS and MERS, patients had immunity to re-infection for up to three years due to the presence of specific neutralising antibodies circulating in their body.

"Based on (these) other coronavirus infections in humans, I personally believe there is some protection following SARS-CoV-2 infection (the virus that led to Covid-19 disease).

"We do not know how good the protection is, and whether it will last for weeks, months or years," he said in a statement on Tuesday (April 28).

He said on Sunday (April 26) the World Health Organisation (WHO) had to retract a scientific brief it issued on Friday (April 24) which it stated that currently there was no evidence that people who recovered from Covid-19 and had antibodies were protected from a second infection.

The earlier statement came in response to the idea that governments should grant special documents or "immunity passports" to citizens who test positive for Covid-19 antibodies, allowing them to move about freely and to return to work.

The Friday statement led to an outcry from the scientific community, and the WHO issued a clarification on Sunday, saying that those who had contracted the disease had “some level of protection from reinfection”.

“What we don’t yet know is the level of protection or how long it will last”, said WHO's Sunday statement.

Dr Lam said he was glad WHO had retracted their original statement which helps to clarify the issues.

He said in China, monkeys given Covid-19 candidate vaccines had shown protection to injection of the virus in a challenge test.

"The phase three vaccine trial in humans is also to test for the efficacy of the vaccine in a large cohort of volunteers and should provide further evidence as to whether the antibody produced will offer protection in a natural environment," he said.

He said in the case of Covid-19, the antibodies to SARS-CoV-2 is expected to offer some level of protection, although it was not known yet how strong the immunity would be and for how long.

"We have to continue monitoring it to gather more evidence of protection and disease progression," he said.

Dr Lam is a renowned medical virologist whose outstanding research in infectious diseases earned him many awards, including the Prince Mahidol Award for Public Health from Thailand, a Knighthood of the National Order of Merit by France and the prestigious Merdeka Award 2013 from Malaysia.

He was central in the discovery of Nipah virus in late 1990s, and was instrumental in developing in-house rapid diagnostic techniques to detect dengue virus.