According to the first global estimates quantifying symptom-less transmission of Covid-19, the virus spreads easily among people living together; even when an infected person is pre-symptomatic or asymptomatic. Published in The Lancet Infectious Diseases journal, the study showed people with Covid are infectious before they develop symptoms as later in their illness. People who are 60 years older are most susceptible to infection.
The study was based on contact-tracing from 349 people with Covid and 1,963 of their close contacts in Guangzhou, China. It included people living together, family not living at the same address, and non-household contacts like co-workers, friends and fellow commuters.
Dr V Ramana Dhara, of the Indian Institute of Public Health, Hyderabad, said, “The study confirms what we already know, which is that household and family clusters are the primary source of infection. The more virus you are exposed to, the more you are likely to get infected, and in high-density housing, where large families live together, infected respiratory droplets can stay suspended in air and infect others.”
“What is significant is the establishment that incubation period is infectious, which means everybody needs to wear a mask all the time. Most people take off their masks inside homes because they feel safe and protected, but given the density of population in India, indoor containment will be a challenge,” they added.
