BEIJING (Reuters) – Days before China’s once-a-year parliament is due to meet, dozens of staff at the Beijing headquarters of Industrial and Commercial Bank of China came down with fever in what turned out to be a novel coronavirus scare.

Beijing has not reported any new coronavirus cases since April 15. The annual meeting of parliament, due to begin in the city on Friday, is China’s most important political gathering since the coronavirus emerged in a central city late last year.

Thirty-three people had been admitted into medical care by midnight on Sunday, said Chen Xin, director of a district health commission, referring to the bank by its address, not by its name.

All of them tested negative for the coronavirus and were instead diagnosed wuith a bacterial respiratory infection, Chen told a media briefing.

Many of the patients had blamed the fever on their building’s air-conditioning system, Chen added.

Earlier on Monday, the central bank in Beijing told its bureaus and departments in an internal notice that ICBC had reported fevers, according to two sources who saw the notice.

The People’s Bank of China (PBOC) said it would review bankers who had been temporarily transferred from ICBC as well as their relatives, and would ask them to work from home for at least a week, the bank said in the notice.

ICBC referred Reuters to a transcript of the Beijing media briefing posted online. PBOC did not immediately respond to a faxed request for comment.

(Reporting by Kevin Huang, Cheng Leng, Ryan Woo and Beijing Newsroom; Additional reporting by Rong Ma)