Coronavirus in India: Contact tracing study shows ‘superspreaders’ behind spike in new Covid-19 cases

A small percentage of Covid-19 infected people have been responsible for large scale spread of the disease in the country, according to the findings of a recently conducted contact tracing study in Andhra Pradesh and Tamil Nadu. The small group of infected people who are termed as ‘super-spreaders’ along with Covid-19 infected children have been the biggest source of the spread of the disease in the majority of new infections, PTI reported.

Researchers from the governments of Tamil Nadu and Andhra Pradesh have found that about 70 percent of the infected people in the country were not the source for infecting even a single new patient. On the other hand, the researchers have zeroed in on a small group of about 8 percent Covid-19 patients who are understood to have transported the virus to about 60 percent of the new Covid-19 infections. The study also found that most cases of Coronavirus infections and resultant deaths were found in the 40-69 year age group.

The study which was published in the journal Science on Wednesday analysed the disease transmission patterns in over 5.75 lakh people who were exposed to the virus by being in contact with about 84,000 confirmed patients of Coronavirus in Andhra Pradesh and Tamil Nadu. On the basis of the findings of the study, scientists including Ramanan Laxminarayan from the Center for Disease Dynamics, Economics, and Policy, New Delhi, said that in most cases, infections and death occurred among people in the age group of 40-69 years, in contrast to the prevalence of infection in higher age groups in higher income countries. The study also said that the risk of infection was also the greatest among the contacts of Coronavirus patients in the same age group.

According to the data collected by the researchers, only 17.9 percent Covid-related deaths before August 1 occurred among patients aged above 75 in the two states. On the other hand, Covid-related deaths of patients aged above 75 accounted for about 58.1 of the total deaths in the United States.

Considerable difference was also found in the average number of days spent by Coronavirus patients in hospital before succumbing to the disease in these two states in comparison to the higher income countries. While the median number of days of patients in hospital was five before death in these two states, the median number of days spent in hospital was 13 days for patients who died of the disease in the US.

Through the method of follow up testing of the contacts of confirmed Coronavirus cases, the researchers found that 70 percent of the patients did not spread the disease to anyone, about 8 percent of patients caused infection in 60 percent of the new cases.