Decline in Covid-19 cases: Docs cite 'herd immunity- The novel coronavirus can live on various surfaces from four to 16 hours

PARAG BISWAS, SNS, SILIGURI. 29 DECEMBER 20 : While several countries in the world are struggling to come to grips with two mutated and highly infectious strains of the coronavirus, and while many UK returnees in India are testing positive for the new strains, Siliguri reported only six cases yesterday and the country reported 16,432 new covid-19 cases in the past 24 hours ending at 8.00 am on Tuesday the lowest in daily cases in six months, since June 23.

Experts believe that this steady and significant decline in the number of Covid cases could be mainly because a larger segment of the population in India than we currently estimate could have already been infected by Covid- 19, the disease caused by the novel coronavirus.

A renowned medical practitioner of north Bengal, Dr Sekhar Chakraborty, who has been treating and monitoring covid patients in Siliguri since the outbreak of the pandemic in March this year, told this correspondent today that the actual prevalence of Covid-19 could have been 10 times higher than the confirmed cases so far.

"If India has reported close to 1 crore conformed cases now, the actual disease prevalence could be over 10 crore. It is possible that the outbreak has moved faster than we have been able to record and it has probably created herd immunity in over 50 percent of our population," he said.

The noted physician attributed the development of herd immunity in India to easy availability of scheduled drugs and medicines in the open markets in the country. "In India, unlike in countries like England, where the two new strains of the coronavirusare spreading rapidly, you do not need a prescription from your health care provider to buy from a medical store, medicines which are used to treat covid-19 such as Ivermectin, Doxycycline, Dexona, Remdesivir and Hydroxychloroquine. Due to increased knowledge and awareness among the patients about the disease and its treatment now, people with mild symptoms are not going for a Covid test and are isolating themselves and taking these medicines to cure themselves. As a result, herd immunity has been created more quickly and easily in India than in the European countries, and I am certain that even the new strains of the novel coronavirus will not be able to cause much infection in India," he said.

Dr Chakraborty also suggested that the novel coronavirus might have lost some of its severity because of increased exposure. "Every virus has a certain biological life-span. The novel coronavirus can live on various surfaces from four to 16 hours. If during this period, it does not get any potential genuine host to multiply, it cannot survive. Due to population immunity in India, it is perhaps not finding too many potential hosts, and thus, is losing its virulence. However, there is currently no evidence to prove it and we shall have to wait for the results of the findings of the various researches being conducted on the virus across the world at present," he said.

According to the Head of the Department of Microbiology, North Bengal Medical College and Hospital, Dr Arunava Sarkar, who is part of one such research team, like many other Covid testing centres in India, their hospital had also sent 80 selected samples from its Covid testing centre to theNational Institute of Virology in Pune for studies, which would indicate if population immunity was developing among the Indians.

"We have sent 20 samples each from September, October, November and December for sequencing at NIV. The various sequencing and other studies on the different samples from all over India as well as the randomized researches on various age-groups will indicate the degree and level of generation of anti-bodies among different segments of our population. The current decline may be due to a development of immunity against the virus owing to our BCG inoculation process, which is not conducted in many countries of the world. It may also be a seasonal phenomenon. But since there is still no empirical evidence of herd immunity, it is advisable for us to follow the standard operating procedures strictly to prevent a second wave," he said.