New Delhi, October 1
COVID-19 transmission in India has been primarily driven by “super-spreaders” or a small percentage of infected people, according to the country’s largest contact tracing study, which also shows that children are key to the spread of the new coronavirus. .
Researchers, including those from the government of Tamil Nadu and Andhra Pradesh, found that more than 70 percent of COVID-19-infected patients in the country did not infect any of their contacts, while 8 percent of those infected they accounted for 60 percent. of new infections observed.
The study of more than half a million people in India found that both cases and deaths due to the disease had been more concentrated in the age group 40 to 69 years than in high-income countries, among other trends.
The researchers also found a high prevalence of infection among children who were contacts of other cases their own age.
The study, published in the journal Science on Wednesday, evaluated disease transmission patterns in 5,75,071 people exposed to 84,965 confirmed COVID-19 cases in the two states, based on data collected by tens of thousands of contact markers. .
According to scientists, including Ramanan Laxminarayan of the New Delhi Center for Disease Dynamics, Economics and Policy, the findings offer a glimpse into the trajectory of the pandemic in a low- and middle-income country, where the majority of cases have occurred. of COVID-19.
Based on the data, the scientists said that both cases and deaths in the two Indian states were concentrated in younger cohorts than expected from observations in higher-income countries.
The study noted that contacts of the same age were associated with the highest risk of infection, a pattern that the researchers said was strongest among children ages 0 to 14 and among adults 65 and older.
They said the ratio of deaths to the number of infected people, known as the case fatality rate (CFR), ranged from 0.05% between the ages of 5 and 17 to 16.6% in ages over 85 years.
The researchers also observed that COVID-19 patients in the two states had an average stay of five days in the hospital before death compared to 13 days to death from the date of admission to the hospital in the United States. .
Follow-up testing of exposed contacts revealed that 70 percent of infected people did not infect any of their contacts, while 8 percent of coronavirus-positive patients accounted for 60 percent of new infections observed.
The researchers said that this finding presented the largest empirical demonstration of superpropagation, which is when an unusually large number of individuals were infected by a few other people.
They said the findings “may indicate the identification of less serious infections through active case finding.”
“Andhra Pradesh and Tamil Nadu are among the states in India with the largest workforce in health care and public health expenditures per capita and are known for their effective models of primary health care delivery,” the study noted.
He said that 63 percent of those who died had at least one comorbidity and 36 percent had two or more underlying health conditions that made them more susceptible to the disease.
About 45 percent of those who died were diabetic, the scientists said.
Unlike observations in high-income countries, they said that deaths in India were concentrated in the ages 50 to 64. In the two Indian states in particular, they said that only 17.9 percent of COVID-19 deaths that occurred on or before August 1, 2020, were among people over the age of 75, compared to 58. , 1 percent of deaths from the disease in the US.
“This study was made possible by the significant contact tracing effort in Andhra Pradesh and Tamil Nadu, which involved tens of thousands of healthcare workers,” Laxminarayan said.
“The results on disease transmission and mortality have the potential to inform policy to combat COVID-19. The study also speaks to the ability of research emerging from India to help inform the global response to COVID-19, “he added. PTI
