China will start releasing information from Wednesday on coronavirus patients who show no symptoms and order them into quarantine, a health official said on Tuesday after the Chinese mainland saw its first rise in infections in five days.

As local infections peter out and new cases surface among travelers, the existence of virus carriers with no symptoms is fueling concern that people could be spreading it without knowing they are ill.

From Wednesday, the daily report of the National Health Commission will include details of such cases for the first time, Chang Jile, a commission official, told a briefing. People in close contact with them face 14 days of medical observation.

Asymptomatic patients under observation numbered 1,541 by Monday, with 205 cases coming from overseas.

Monday’s 48 new infections and one death in China’s mainland were up from 31 the previous day, reversing four days of declines. All were imported, taking China’s tally of such cases to 771, with no new local infection reported.

Many are students returning from overseas. Thirty-five Chinese students studying abroad have been diagnosed with COVID-19 so far, with 11 already cured, education ministry official Liu Jin said.

Shanghai saw 11 new imported cases on Monday, while Beijing had three. Among the newly diagnosed cases in Shanghai, six are Chinese students studying abroad — five in the UK and one in France. Shanghai has 170 such cases and another 21 suspects are undergoing tests. Three patients had recovered and were discharged.