Some 242 deaths from the new coronavirus were recorded in the Chinese province of Hubei on Wednesday – the deadliest day of the outbreak.
There was also a huge increase in the number of cases, with 14,840 people diagnosed with Covid-19.
Hubei has started using a broader definition to diagnose people – which accounts for most of the rise in cases.
China sacked two top officials in Hubei province hours after the new figures were revealed.
Until Wednesday’s increases, the number of people with the virus in Hubei, where the outbreak emerged, was stabilising.
But the new cases and deaths in the province have pushed the national death toll above 1,350 – with almost 60,000 infections in total.
China has been accused of suppressing the full extent of the outbreak in the past, says the BBC’s Nick Beake in Hong Kong.
Professor David Heymann, Professor of Infectious Disease Epidemiology from the London School of Hygiene and Tropical Medicine, said: “What has happened in China is that they have changed the definition of what the disease really is – now they are taking people who have lesser symptoms.
“The deaths are quite worrisome, there are an increased number of deaths reported, but if you look overall at the total number of deaths and the total number of cases, the fatality ratio is about the same as it has been – but it is still high, as high as the death rate in influenza.”
Only Hubei province – which accounts for more than 80% of overall Chinese infections – is using the new definition to diagnose new cases.
Just about everyone who’s been following China’s official coronavirus numbers has been able to see that they have been incomplete. Government officials know this too. There’s no way they’ve accounted for everybody infected. How could they?
But at least we had what appeared to be a trend. We could observe the pattern to try and estimate the trajectory of outbreak.
Now that’s gone too.
You can understand why it has been decided that people who have virus symptoms, plus a CT scan showing chest infection, are now being counted in the “definitely infected” column.
However, this has thrown the trend mapping into chaos.
Over the past 24 hours, in Hubei alone, nearly 15,000 people were moved into the infected column. This would have sent shockwaves around the world, but actually, if you consider Wednesday’s cases by the old definition, the rate could well mean another day of decline: a completely different picture.
So now, we’re scratching our heads: do we start looking at the pattern all over again from Thursday onwards?
This has also left many wondering what the real death rate must have been over recent weeks and the extent to which we should be treating the overall figures seriously anyway.
Meanwhile, the Communist Party secretary in Hubei, Jiang Chaoliang, has been replaced by the Shanghai party chief, Ying Yong, according to state media. The party chief of the capital city, Wuhan, has also been relieved of his duties.
It is the first major change of Hubei party officials since the outbreak began.
What is the new diagnosis method?
The province now includes “clinically diagnosed cases” in the number of confirmed cases.
This means it includes those showing symptoms, and having a CT scan showing an infected lung, rather than relying only on the standard nucleic acid tests.
Of the 242 new deaths in Wuhan, 135 are such “clinically diagnosed” cases.
That means, even without the new definition, the number of deaths in Hubei on Wednesday was 107 – a new high for the province.
The province’s 14,840 new infections include 13,332 clinically diagnosed cases.
Overall, the province now has 48,206 confirmed infections.