Coronavirus: Could asymptomatic people be driving the spread in India?2 min read . Updated: 22 Mar 2020, 02:01 PM IST
- Until Saturday, 17,000 samples were tested of those who showed symptoms, had travel history
- Symptoms are not common for all and could take up to 14 days to show
New Delhi: There are rising concerns that people with mild or no symptoms may be driving the spread of novel coronavirus in India amid the government's stance that there is no community transmission in the country as yet.
Since asymptomatic people do not require medical help, scientists say, they could be incubating the virus within and transmitting it to others.
Researchers in US and China, in a recent detailed analysis, estimated that by 18 February, there were at least 37,400 people infected in China of whom authorities did not know about and they ended up exposing the larger population to the virus.
"By our most conservative estimate, at least 59% of the infected individuals were out and about, without being tested and potentially infecting others. This may explain why the virus spread so quickly in Hubei and is now circulating around the world," lead author Wu Tangchun, from Huazhong University of Science and Technology in Wuhan, told journal Nature. The findings are yet to be peer-reviewed.
The symptoms -- sore throat, fever, shortness of breath, running nose and even headaches -- are not the same for all and could take up to 14 days to show. Some people have also reported lack of smell and taste.
Those who were infected but exhibited no symptoms may have probably slipped past temperature checks at airports, or remain un-reported or undetected because authorities are not doing enough testing.
Another research published in the journal Science says the number of undetected cases could be higher and estimates that 86% of all infections were un-documented in China before 23 January when Wuhan was placed under lockdown. "Countries must urgently increase viral surveillance, testing and isolation of the un-documented infections if they are to fully control SARS-CoV2," it says.
This is crucial for India, where the testing rate of samples remains one of the lowest in the world. Despite the surge in number of confirmed cases, India had tested around 17,000 samples until Saturday, largely people who showed symptoms, had travel history or came into contact with someone infected.
But as cases have surged past 341, health authorities had to revise their testing criteria to include all asymptomatic cases who undertook international travel in the last 14 days and those who are direct and high-risk contacts of a confirmed case and would be tested between day 5 and day 15 of them coming into contact.
In addition to these, all symptomatic contacts of confirmed patients and those admitted in hospitals with Severe Acute Respiratory illness (fever/cough/shortness of breath) would also be tested. Health workers remain on priority and would be tested if they show any symptoms - mild or severe.
“Community transmission has not been documented in India till now, its mostly related to travel and local transmission from imported cases and their contacts. Once community transmission is documented, the testing strategy will undergo changes to evolve," the Union health ministry said.