Chinese authorities have shifted their focus to tackling “silent”, or asymptomatic, carriers of the coronavirus as part of the next phase of the pandemic, amid concern among US health chiefs that a quarter of patients do not suffer symptoms.

The National Health Commission in China said it would start releasing a tally of asymptomatic patients from Wednesday and would order those cases into quarantine for 14 days, after the mainland witnessed its first rise in infections in five days.

Authorities reported 130 new asymptomatic cases on Wednesday, bringing the total number of such cases under observation to 1,367. Previously, China has regarded asymptomatic patients as a low risk and not included them in their tally of confirmed cases. Asymptomatic patients, found through tracing the contacts of confirmed cases, had been quarantined and then released if they did not show symptoms.

Recent new infections likely caused by asymptomatic patients have prompted widespread public concern as the country lifts lockdown measures and citizens go back to work. On Monday, Chinese premier Li Keqiang called for increased tracking and monitoring of patients without symptoms amid fears of a resurgence of cases, leading several provinces to introduce tougher measures on Tuesday. In Zhejiang, all asymptomatic patients undergo mandatory medical observation at a hospital for 14 days.

Those concerns were reflected on Tuesday by Robert Redfield, the director of the US Centers for Disease Control and Prevention (CDC), who said in a rare interview that as a many as one in four cases have no symptoms. He told NPR: “That’s important because now you have individuals that may not have any symptoms that can contribute to transmission, and we have learned that in fact they do contribute to transmission.”

As a result, the CDC was now “aggressively reviewing” its recommendations on use of face masks, potentially extending their use based on the assumption that more people in “high transmission zones” were already infected but without symptoms.

US healthcare workers are already facing acute shortages of personal protective equipment, and Dr Anthony Fauci, the head of Donald Trump’s coronavirus task force, warned on Tuesday that, although widening use of masks was being considered, it must not come at a cost to frontline health workers.

Trump advised the public on Tuesday to “use a scarf if you want ... rather than going out and getting a mask.”

Chinese researchers estimate that 59% of those who contracted the virus had mild or no symptoms. Documents seen by the South China Morning Post reportedly showed more than 40,000 asymptomatic patients that would not have been included in China’s total number of infections of more than 80,000.

By Monday, the latest day for which data is available, total infections stood at 81,518 in mainland China, with 3,305 deaths.

Fears in China have increased after a case emerged in Henan province in which a women was confirmed to have been infected after coming into contact with an asymptomatic patient. The country is seeking to loosen lockdowns but has achieved mixed results with cinemas, tourist attractions and a smattering of cafes and karaoke bars ordered to close after a tentative re-opening.

On Tuesday, China’s Global Times newspaper reported the transmission risk of asymptomatic patients was similar to those with symptoms. It said 6.3% of a confirmed case’s close contacts were infected with the virus, as opposed to 4.4% for an asymptomatic carrier, according to the Ningbo Center for Disease Control and Prevention in Zhejiang Province.

In other developments around the world:

Donald Trump has warned of a “very painful” two weeks ahead, amid forecasts from officials of as many as 240,000 deaths in the US, even with existing containment measures in force.

The captain of the aircraft carrier the USS Theodore Roosevelt has urged authorities to evacuate at least 4,000 sailors from his vessel in Guam to tackle an outbreak of the virus. Lives were at risk, said Captain Brett Crozier, because the vessel did not have enough quarantine facilities.

Brutal enforcement of lockdown measures across the world has emerged, with reports of deaths during curfew enforcement, beatings and other humiliating punishments.

France, Italy, Spain, Russia and the UK recorded their highest daily death tolls. UK deaths were up 381 from 1,408 on the previous 24 hours and represents a 27% day-on-day increase – by far the biggest. Italy’s death toll rose by 837.



