Comprehensive Analysis of 85,000 COVID Cases Reveals New Insight on Transmission

A comprehensive analysis among “575,071 individuals exposed to 84,965 confirmed cases” of COVID-19 in India, revealed “infection probabilities ranged from 4.7-10.7% for low-risk and high-risk contact types”.

High-risk contact types referred to those living in the same household, having direct physical contact, and/or touching bodily fluids. The data implies that if a member of your household contracts COVID-19, there is a 10.7% chance you contract the disease. Or if you shared something like a room, train car, or cab with someone who has COVID-19, the risk of transmission is 4.7%.

“No positive contacts were identified for 70.7% of index cases for whom reliable contact-tracing data, including test results, were available”, i.e., 70.7% of the 85,000 studied COVID-19 cases did not transmit the disease onto anyone else.

Analysis also showed that the fatality ratios spanned as low as 0.05% for ages 5-17 years to as high as 16.6% for ages 85 years and older. Of the examined fatalities, the most prevalent pre-existing conditions were diabetes (45.0%) and high blood pressure (36.2%).

Individuals were tested “5-14 days after their contact with a primary case, irrespective of symptoms, to identify onward transmission”. Roughly seven contacts were tested for each of the 85,000 case subjects.