The potential of the asymptomatics and the mild COVID19 cases
Dr. Nerges Mistry, The Foundation for Medical Research, Mumbai. E-mail: fmr@fmrindia.org
Willy nilly the ICMR has transitioned from dismissing community transmission into accepting that it may be a reality. A big gap in our knowledge of COVID19 is the variety of immune responses that it may engender in different individuals and the possibility of the presence of viral carriers.
As reported by researchers from Columbia University asymptomatic infections were first seen in China and then subsequently from Germany and Italy. Measured to be only 55% contagious than those with symptoms, they were shown to contribute to 79% of infections. Prevalence of such transmitters were estimated to range from 1 asymptomatic to 5–10 symptomatics.
Given their importance in tracking of transmission of COVID19, the restricted sampling strategy in SARIs admitted in hospitals, begs questioning especially since temporal details such as duration of illness with respect to initiation of testing in various locales is obscure. In line with the recommendation of Dr.Ashish Jha from Harvard University, an epidemiology based random sampling of asymptomatic individuals in circumscribed areas of COVID19 clusters may yield a better picture of extent of community transmission and yield insights into the immune features of the Indian epidemic.
If we institute insightful surveillance, we will expect to see individuals with no overt or extremely mild symptoms reflecting in all probability a carrier or quasi carrier state. It would be logical to hypothesize that these would be younger people, healthy enough not to fall prey to the cytokine storm set off by the virus, but not capable of preventing viral spread. What would be their predominant age group, their health profile and the repertoire of their innate immunity. Could we not pick up correlates of protective immunity from these individuals which would help in the evaluation of a vaccine (apart from a robust IgG response).
A second angle of this issue would be a deep study of viral genomics from viral isolates from such individuals. Are these isolates any different from those that infect individuals who have increased severity of symptoms normalized for age and health profile.
The recovering Chinese population in Wuhan many of whom whose retrospective data would have been recorded would be an excellent source for the study of the abovementioned issues strengthened with the creation of a strategically selected viral repository. Have our national agencies, ICMR and DBT had the foresight to create such a viral repository complete with valuable metadata.
Whilst we fight the epidemic with conventional measures, the search for helpful knowledge that illuminates how our species and other protected species reacts to COVID19 over a period of time should not be belittled nor postponed. The ICMR (as its very name suggests) could have instituted a dedicated cell for basic research to understand the features of the COVID 19 epidemic in India, e.g. rapid genomics to understand the virus make-up and its evolution, the significance of antibody responses in COVID infection and the protective corelate of human response to COVID 19.
This knowledge will contribute significantly to our survival in the next pandemic when it comes. Its not a question of “if”.
