THE number of people dying from coronavirus is “70 per cent higher than first feared” – as the killer bug is declared a pandemic.
The World Health Organisation (WHO) has estimated that the global mortality rate from Covid-19 is about 3.4 per cent.
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Initially, the agency had suggested that, based on early data from January, the death rate was about two per cent.
But WHO Director-General Dr Tedros Adhanom Ghebreyesus said last week that it was much higher than they had first estimated.
On March 3, he told a press conference: “Globally, about 3.4 per cent of reported Covid-19 cases have died.
“By comparison, seasonal flu generally kills far fewer than one per cent of those infected.”
That jump from two to 3.4 per cent means the death rate is 70 per cent higher than the WHO had initially estimated.
Statistics from China show the death rate was between two and four per cent in Hubei province – where the outbreak began in the city of Wuhan – and 0.7 per cent in other parts of the country.
However, analysts have said that this figure is likely an overestimate – and one even branded it “misleading”.
That’s because the higher figure of 3.4 per cent was calculated by dividing the number of deaths by the number of officially confirmed cases.
It’s thought there are many more mild cases that aren’t reported, which would bring the mortality rate down significantly.
For the UK, where there have been eight deaths and 460 confirmed cases, the mortality rate is believed to be much closer to one per cent – or lower.
UK rate is lower
Prof Chris Whitty, chief medical officer for England, said: “I am reasonably confident one per cent is the upper rate of mortality.
“If you are missing all the mild cases, all the asymptomatic cases, you end up with an exaggerated view of what the mortality rate is.”
Dr Toni Ho, a consultant in infectious diseases at the MRC-University of Glasgow Centre for Virus Research, said: “The quoted mortality rate of 3.4 per cent is taken from confirmed deaths over total reported cases.
“This is likely an overestimate as a number of countries have had limited testing.
“Hence few of the mild cases have been picked up, and what we are observing is the tip of the iceberg.”
Prof Christl Donnelly, from the University of Oxford, and WHO Collaborating Centre for Infectious Disease Modelling, Imperial College London, explained: “In an unfolding epidemic it can be misleading to look at the naïve estimate of deaths so far divided by cases so far.
“Earlier this naïve estimate gave a roughly two per cent case fatality ratio. Now it is 3.4 per cent.
“This increase is due to the delay from the time it takes for individuals to progress from being diagnosed as cases to dying.
“When we make a robust statistical estimate of the case fatality ratio, we adjust for this diagnosis-to-death interval and the adjustment can substantially increase the naïve estimate.”
In an unfolding epidemic it can be misleading to look at the naïve estimate of deaths so far divided by cases so far
Prof Christl Donnelly
She added: “If the case-mix of those being diagnosed stays the same, then it is likely that the 3.4 per cent figure will increase further.
“Our analyses have included estimates of the case fatality ratio, but also the infection fatality ratio.
“The infection fatality ratio is the proportion of infections (including those with no symptoms or mild symptoms) that die of the disease.
“Our estimate for this is one per cent. This is lower than the observed 3.4 per cent figure because asymptomatic and mildly symptomatic cases are included in the denominator.”
By comparison, about one per cent of people who contract seasonal flu die each year.
Speaking on This Morning earlier this week, Dr Sara Kayat said: “We know that the flu has a mortality of one per cent. It’s an infection that we know so much about.
“But the coronavirus is new, we don’t know that much about it.
“The World Health Organisation says the mortality rate is around 3.4 per cent but in the UK modelling has suggested it’s more like one per cent.
“It’s somewhat equivocal to that of the flu but with the flu, we have vaccines – whereas we don’t have vaccines for the coronavirus.”
Last night, the WHO declared the coronavirus outbreak a pandemic.
Dr Tedros said the number of cases outside China has increased 13-fold in the past two weeks, and the number of affected countries has tripled.
He said there had been “alarming levels of inaction” in some parts of the world.
But Dr Tedros advised that despite the change in the language, WHO is still advising countries to remain in the containment phase.
However, Boris Johnson is expected to accept that the coronavirus outbreak can no longer be contained in the UK, signalling the start of the next phase in the battle against Covid-19.
The Prime Minister will chair a Cobra meeting at lunchtime on Thursday where ministers are expected to agree to move into the “delay” stage of the process.
Moving to delay would mean social distancing measures could be brought in, such as restricting public gatherings and issuing more widespread advice to stay at home.
The expected shift in UK policy came as Donald Trump dramatically escalated the US response to the coronavirus pandemic, slapping a travel ban on continental Europe.
The suspension of travel between the United States and Europe – excluding the UK and Ireland – will last for 30 days starting on Friday.
Meanwhile, the Chinese government’s senior medical adviser said the pandemic is likely to be over by June.
Zhong Nanshan, an 83-year-old epidemiologist renowned for helping combat the SARS outbreak in 2003, said a lot of imported cases into China are asymptomatic patients and the re-infection rates among recovered patients are low.