Prof Chuang did not disclose the name of the mystery senior Beijing health official who confirmed the human transmission conclusion, although he revealed it was not George Gao, head of the Chinese Centre for Disease Control and Prevention.

He does not know how far up the chain of command the knowledge reached, nor why local officials chose to sit on the alarming data for days before warning the public or taking more preventive action.

On January 22, as millions travelled round China for Lunar New Year celebrations, the WHO issued a statement saying there was evidence of human-to-human transmission in Wuhan but more investigation was needed to understand the full extent of transmission.

Prior to the statement, on January 18, Wuhan’s leaders gave the green light to a Guinness world-record attempt to create the largest ever potluck dinner, with 40,000 families in attendance. By early February, dozens of residential buildings in that neighbourhood had been designated “fever buildings.”

Zhou Xianwang, then Wuhan mayor, said permission for the event was granted on the basis that human transmission was “limited.”

But for Prof Chuang, who by that point was back in Taipei warning the Taiwanese government to tighten border controls and step up its epidemic prevention measures, “limited” still meant the virus was spreading between humans.

He does not know if the pandemic could have been stopped in Wuhan but said: “At least they could have tried to minimise the impact and to contain the pandemic in a limited area, limiting the possibility of it spreading to the rest of the world.”

It could have been a mistake, or the authorities were perhaps not taking the situation seriously enough, he suggested.  

However, the Wuhan briefing had raised more questions than it answered. He was “suspicious” when their hosts only gave an oral presentation, without offering written epidemiological, objective data as would have been expected. “I had kind of an off feeling,” he said.

The session began with a statement clarifying the number of cases was 41, with 28 linked to the Huanan market. No explanation was given for the remaining 13.

With hindsight, Prof Chuang realised they had been given “outdated” information. “They only released what they wanted to release,” he said.

Taiwan has long distrusted China on healthcare matters. Taipei has previously accused Beijing – which claims Taiwan as its own territory – of delaying vital assistance during the deadly Sars outbreak in 2003.

But Hong Kong experts also felt growing disquiet in early January 2020. One, who had close knowledge of the Chinese CDC at the start of the pandemic, said he was “horrified” when officials insisted the situation was under control even as Wuhan locked down on January 23.

The expert, who spoke anonymously out of fear of repercussions, alleged the Chinese had initially persuaded the WHO not to call the crisis a Public Health Emergency of International Concern – despite evidence to the contrary – “so they didn’t lose face in the eyes of the world.”

This PHEIC declaration was finally made on January 30.

However, Prof Chuang admits that he too, in the chaotic early days of the pandemic, had no idea about the full significance of the meeting or the predicament the world was now facing.

“I didn’t expect that from then on Covid-19 would become a pandemic, and very serious infection, until now. I didn’t expect that,” he said.

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