Children could be silent carriers of Covid-19 in community, Hong Kong researchers find

A handout photo. The coronavirus survived in stool samples for as long as 36 days in the case of one child.
PHOTO: Reuters via Nexu Science Communication

Children could be more contagious silent carriers of the coronavirus , with over 40 per cent of confirmed cases aged three and below in Hong Kong displaying no symptoms, local researchers have found.

Data collected locally by researchers at Chinese University showed the coronavirus survived in stool samples for as long as 36 days in the case of one child.

Researchers in the city also cited a separate study in the United States that showed toddlers had significantly higher viral loads than even adults who needed intensive care, making them more contagious.

“They are more likely to become a hidden source of infection, and may play a role in community transmission,” Professor Ng Siew-chien, associate director of the Centre for Gut Microbiota Research at the university, said on Tuesday (April 6).

“While we are working intensively to prevent high-risk individuals from being infected, it is important to come up with a solution to avoid unfavourable outcomes in young children.”

The researchers said stool sample testing could be an accurate, safe and effective way to screen for Covid-19 among children, especially as schools will gradually reopen after the Easter break.

A handout photo. (From left) Professor Albert Martin Li, Professor Ng Siew-chien and Professor Paul Chan.
PHOTO: South China Morning Post

Last month, the government said it would ease restrictions on in-person classes to allow two-thirds of pupils to return to schools when term restarts after Easter.

Chinese University started providing free stool sample screening for children last March, completing 17,500 tests between then and March 25 this year. Among those, 22 children tested positive, a rate of up to two for every 1,000 tested.

Hong Kong government public health advisers.
PHOTO: South China Morning Post

Asymptomatic infections made up 70 per cent of the confirmed cases, while 90 per cent were aged six or younger.

Data also showed Hong Kong had a higher proportion of Covid-19 infections among children than mainland China, Italy, Spain and the United States. Up until March 25, out of 11,429 confirmed Covid-19 cases in Hong Kong, 201 were children aged three and below, 40 per cent of whom were asymptomatic.

Hong Kong government.
PHOTO: South China Morning Post

Since then, the coronavirus situation in Hong Kong has eased, with the city confirming just seven new infections on Tuesday, four of which were imported. All three local ones were linked to existing cases. The city’s tally now stands at 11,531 confirmed cases, with 205 related deaths.

Professor Paul Chan Kay-sheung, chairman of Chinese University’s microbiology department, called for more attention on younger populations as they could easily spread the virus through the community.

Another of the researchers, Professor Albert Martin Li, reminded parents to have their children screened for Covid-19, especially if they were exhibiting symptoms such as a fever and cough, which were similar to those of the flu.

“This is especially important for those who feel sick after visiting high-risk areas, or the residential building they live in has to undergo compulsory testing, or there is a reported sickness of unknown cause in school personnel and students.”

This article was first published in South China Morning Post.