According to a report by the Washington Post, “Asymptomatic Covid-19 cases could be the key to understanding how a larger population can develop immunity against the virus”.
The report is based on the research conducted by Monica Gandhi, Professor of Medicine and Associate Division Chief (Clinical Operations/ Education) of the Division of HIV, Infectious Diseases, and Global Medicine at UCSF/ San Francisco General Hospital.
According to Monica Gandhi, “It is an intriguing hypothesis that asymptomatic infection triggering immunity may lead us to get more population-level immunity. That itself will limit spread.”
Asymptomatic patients of coronavirus account for about 40 per cent of the total infection cases.
The report said, “Further research into why a large number of people infected with the virus show no symptoms and the overall diversity of the illness, can help researchers better understand pandemic control measures. It can help in developing therapeutics and vaccines as well as get a better insight into how it may possibly create a pathway to herd immunity”.
Studying the existing immunity against the coronavirus in some people can help to unravel the reason behind a larger part of the population developing almost no symptoms of the infection. Some studies focused on “T-Cells” memory have estimated that people with a history of having been exposed to other coronaviruses such as a common cold, may have developed the immunity.
According to a study by Alessandro Sette, Shane Crotty and others at the La Jolla Institute for Immunology, “T cell reactivity against SARS-CoV-2 was observed in unexposed people; however, the source and clinical relevance of the reactivity remains unknown. It is speculated that this reflects T cell memory to circulating ‘common cold’ coronaviruses. It will be important to define the specificities of these T cells and assess their association with COVID-19 disease severity and vaccine responses”.
Other researchers estimate that pre-existing vaccines such as the BCG (Bacille Calmette-Guerin, which is a vaccine for tuberculosis) have the potential to elicit positive immune responses against the COVID-19 Virus Infection.
According to research published in one of the journals of the non-profit American Association for the Advancement of Science, BCG vaccine delays the infection rate and death rate in Covid-19 patients.
However, experts are of the opinion that asymptomatic cases should rather be a matter of worry. The transmission rate found in asymptomatic cases is 75 per cent.
US virologist and expert Dr Anthony Fauci remarked theories around asymptomatic cases of COVID-19 as relatively premature.
He said, “There are so many other unknown factors that may determine why someone gets an asymptomatic infection. It’s a very difficult problem to pinpoint one thing.”