Death rates of coronavirus may be HALF initial estimates by world health chiefs, promising study finds
- International researchers compiled data on COVID-19 cases in Wuhan, China
- They found that overall, the proportion of patients that died was 1.4 per cent
- World Health Organization said in early March the death rate was 3.4 per cent
- The preliminary findings come as the global death toll nears 10,000
- The scientists suggested focusing on how to reduce the severity of the illness
- Coronavirus symptoms: what are they and should you see a doctor?
The death rate of coronavirus may be half of what world health chiefs expected it to be, according to a study.
International researchers compiled data on coronavirus cases in Wuhan, the Chinese city of 11million people where the deadly disease emerged in December 2019.
They found that, overall, the number of people who died after getting sick with the coronavirus was 1.4 per cent.
In comparison, estimations by the World Health Organization in early March said 3.4 per cent of diagnosed patients had died.
And the true figure is likely to be even lower because so many people are believed to be going undiagnosed.
By comparison the death rate of flu is around 0.1 per cent.
Coronavirus patients often don’t know they’re infected – as many as eight out of 10 could have no symptoms in the early stages of an outbreak, according to one study –because they get such mild signs that they don’t think anything of it.
The study, which has not yet been reviewed by scientists, comes as more than 9,300 people around the world have died and more than 224,000 have been confirmed to be ill.
The death rate of coronavirus may be half that initially thought be world health chiefs, according to a study on Wuhan partients. Pictured, masked medical staff talking to a patient at Red Cross Hospital in Wuhan in China’s central Hubei province on March 10
The preliminary findings come as the global death toll of COVID-19 nears 10,000, currently at 9,249, with more than 224,000 infected. A patient suffering from coronavirus disease (COVID-19) is seen in an intensive care unit at the Oglio Po hospital in Cremona, Italy
HOW DO CORONAVIRUS DEATH RATES VARY BY COUNTRY?
These are the death rates of the countries with the largest coronavirus outbreaks, according to Thursday’s data.
Death rates may not be directly comparable. For example, the UK’s rate is inflated because it only tests people in hospital, who are more likely to die, so the ratio of confirmed cases to deaths is smaller.
The study, led by Professor Joseph Wu of the University of Hong Kong, was focused on the city of Wuhan, where the first cases of COVID-19 were reported.
Professor Wu and colleagues from Harvard University used published data on 425 early confirmed cases and 41 fatalities in Wuhan.
But they wanted to get a bigger picture of how many people in the city, which is in the Hubei province, had the disease but showed no symptoms.
Hospitals had been overwhelmed in Wuhan and milder cases were unlikely to have been tested.
The team used a range of global data sources to estimate the full number of cases within Wuhan by taking into account the location and timing of cases outside of the area to work out how many people could be expected to have had it.
By studying real-life patients they found the average time from the start of symptoms – a fever or a cough – to death was 19 days, on average. It ranged between 16 and 24 days.
They worked out that the proportion of patients who died was 1.4 per cent, with a possible range from 0.8 per cent to two per cent.
Mumps – 0.01%
Flu – 0.1%
Measles – 0.2%
COVID-19 – 3.4% (estimated)
Dengue fever – 5% with treatment
Zika – 8.3%
SARS – 10%
Middle East Respiratory Syndrome (MERS) – 34%
Ebola – 50%
Sources: BMJ, WHO, MedScape, CDC
For those aged 15 to 64 years, the average fatality rate was 0.5 per cent, with a reasonable range of between 0.2 per cent and 1.3.
Over 64s had a fatality rate of 2.7 per cent, with low and high estimates of 1.5 per cent and 4.7 per cent.
The findings support what officials have known for a long time – that the elderly are more at risk of death from COVID-19.
However, it is significantly below earlier estimates of two to three per cent death rate which had been predicted by the World Health Organization (WHO).
The WHO released a statement on March 3 that said: ‘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.’
It is also lower than the four per cent death rate which divides deaths in China (3,245) by confirmed cases (80,928).
However, Professor Wu and colleagues said their estimated death rate is still ‘concerning’.
The probability of dying from COVID-19 after developing symptoms was 1.4 per cent, as low as 0.8 per cent and as high as two per cent, the study in China found. Pictured, workers stand next to coffins and remains of the coronavirus victims, in Bergamo, Italy, 18 March
Professor Wu and colleagues also believe in the worst case scenario, the ‘majority the population will be infected eventually’. Pictured, workers stand next to coffins and remains of the coronavirus victims, in Bergamo, Italy, 18 March
99% OF DEATHS ARE IN THOSE WITH A PRE-EXISTING HEALTH CONDITION
99 per cent of coronavirus deaths in Italy are patients with existing medical problems, a study by the country’s health service has found.
Research into 355 deaths found that only three of the victims, 0.8 per cent, had been clear of illnesses before they were infected.
Nearly half of them – 48.5 per cent – already had three or even more health conditions before they were diagnosed with Covid-19.
Another 25.6 per cent had two other ‘pathologies’, while 25.1 per cent had one.
The research by Italy’s National Institute of Health is consistent with previous findings that people with existing illnesses are more likely to die from coronavirus.
According to the study, the most common of these problems in Italy include high blood pressure, heart disease and diabetes.
Some 76.1 per cent of the patients who died of Covid-19 had previously had problems with high arterial blood pressure, the study found.
More than a third – 35.5 per cent – had diabetes, while 33.0 per cent had suffered from ischemic heart disease.
Nearly a quarter, 24.5 per cent, had suffered from atrial fibrillation. Less common examples included dementia and liver disease.
Scientists have not yet established why people with high blood pressure are more vulnerable to the coronavirus.
The Centers for Disease Control and Prevention in the U.S. says it needs ‘more data to become available’ to investigate the link properly.
‘For the general public, the overriding concern about uncertainty can breed fear, even panic,’ the study authors wrote.
‘There is arguably no greater cause of such anxiety than the relative probability of death and disability caused by infection.
‘While our estimates of symptomatic case fatality risk are concerning, these could be reduced if effective antivirals were identified and widely adopted for treatment of severe cases.’
Outcomes are likely to be better still with measures to ‘flatten the curve’ of the epidemic. This involves slowing the spread of cases by suppressing the peak.
The strategy, adopted by the British Government, has the goal of reducing pressure on health services and bides time to find treatments and vaccines.
Professor Wu and colleagues also believe that in the worst case scenario, the ‘majority of the population will be infected eventually’.
This is based on the fact the virus has never been seen before, meaning no one has immunity to it, and there is currently no vaccine against it.
Unless, they say, drastic public health interventions are applied over prolonged periods ‘and/or vaccines become available sufficiently quickly’.
More realistically, they envision ‘at least a quarter to a half’ will be infected.
But extreme measures, such as closing schools, pubs and restaurants, cancelling sport events and urging social distancing, have been implemented globally following the lead of China.
Wuhan has been sealed off from the outside world since late January, when all citizens were put under a state-imposed lockdown.
Scientists have been scrambling to understand how the never-seen-before coronavirus behaves since it emerged just three months ago.
The authors of this study wrote: ‘The number of severe outcomes or deaths in the population is most strongly dependent on how ill an infected person is likely to become, and this question should be the focus of attention.’
The research team also claim that adults aged between 45 to 65 are three times more susceptible to infection than those aged between 15 and 44 years.
This jumps to 6.4 times in anyone over the age of 64.
But, if their research in Wuahn is anything to go by, only 0.3 per cent of cases will actually be officially recorded due to testing restrictions and asympomatic cases.
The team published the paper on March 13, and it has not been peer-reviewed by other academics yet.
The researchers noted, ‘our modelled estimates have necessarily relied on numerous strong assumptions’ – a variety of data sources were used which each have their own caveats.
The study was undertaken in early February, from which time the WHO has declared a global pandemic and countries have become shut off from one another.
Since then, Wuhan has turned a corner. Hopes were raised when the city reported no new cases for the first time, suggesting its strategies to contain the outbreak may have been successful.
Meanwhile, the virus continues to ravage Europe, the Americas and the rest of the world.
WHAT DO WE KNOW ABOUT THE CORONAVIRUS?
What is the coronavirus?
A coronavirus is a type of virus which can cause illness in animals and people. Viruses break into cells inside their host and use them to reproduce itself and disrupt the body’s normal functions. Coronaviruses are named after the Latin word ‘corona’, which means crown, because they are encased by a spiked shell which resembles a royal crown.
The coronavirus from Wuhan is one which has never been seen before this outbreak. It has been named SARS-CoV-2 by the International Committee on Taxonomy of Viruses. The name stands for Severe Acute Respiratory Syndrome coronavirus 2.
Experts say the bug, which has killed around one in 50 patients since the outbreak began in December, is a ‘sister’ of the SARS illness which hit China in 2002, so has been named after it.
The disease that the virus causes has been named COVID-19, which stands for coronavirus disease 2019.
Dr Helena Maier, from the Pirbright Institute, said: ‘Coronaviruses are a family of viruses that infect a wide range of different species including humans, cattle, pigs, chickens, dogs, cats and wild animals.
‘Until this new coronavirus was identified, there were only six different coronaviruses known to infect humans. Four of these cause a mild common cold-type illness, but since 2002 there has been the emergence of two new coronaviruses that can infect humans and result in more severe disease (Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses).
‘Coronaviruses are known to be able to occasionally jump from one species to another and that is what happened in the case of SARS, MERS and the new coronavirus. The animal origin of the new coronavirus is not yet known.’
The first human cases were publicly reported from the Chinese city of Wuhan, where approximately 11million people live, after medics first started publicly reporting infections on December 31.
By January 8, 59 suspected cases had been reported and seven people were in critical condition. Tests were developed for the new virus and recorded cases started to surge.
The first person died that week and, by January 16, two were dead and 41 cases were confirmed. The next day, scientists predicted that 1,700 people had become infected, possibly up to 7,000.
Where does the virus come from?
According to scientists, the virus almost certainly came from bats. Coronaviruses in general tend to originate in animals – the similar SARS and MERS viruses are believed to have originated in civet cats and camels, respectively.
The first cases of COVID-19 came from people visiting or working in a live animal market in Wuhan, which has since been closed down for investigation.
Although the market is officially a seafood market, other dead and living animals were being sold there, including wolf cubs, salamanders, snakes, peacocks, porcupines and camel meat.
A study by the Wuhan Institute of Virology, published in February 2020 in the scientific journal Nature, found that the genetic make-up virus samples found in patients in China is 96 per cent identical to a coronavirus they found in bats.
However, there were not many bats at the market so scientists say it was likely there was an animal which acted as a middle-man, contracting it from a bat before then transmitting it to a human. It has not yet been confirmed what type of animal this was.
Dr Michael Skinner, a virologist at Imperial College London, was not involved with the research but said: ‘The discovery definitely places the origin of nCoV in bats in China.
‘We still do not know whether another species served as an intermediate host to amplify the virus, and possibly even to bring it to the market, nor what species that host might have been.’
So far the fatalities are quite low. Why are health experts so worried about it?
Experts say the international community is concerned about the virus because so little is known about it and it appears to be spreading quickly.
It is similar to SARS, which infected 8,000 people and killed nearly 800 in an outbreak in Asia in 2003, in that it is a type of coronavirus which infects humans’ lungs. It is less deadly than SARS, however, which killed around one in 10 people, compared to approximately one in 50 for COVID-19.
Another reason for concern is that nobody has any immunity to the virus because they’ve never encountered it before. This means it may be able to cause more damage than viruses we come across often, like the flu or common cold.
Speaking at a briefing in January, Oxford University professor, Dr Peter Horby, said: ‘Novel viruses can spread much faster through the population than viruses which circulate all the time because we have no immunity to them.
‘Most seasonal flu viruses have a case fatality rate of less than one in 1,000 people. Here we’re talking about a virus where we don’t understand fully the severity spectrum but it’s possible the case fatality rate could be as high as two per cent.’
If the death rate is truly two per cent, that means two out of every 100 patients who get it will die.
‘My feeling is it’s lower,’ Dr Horby added. ‘We’re probably missing this iceberg of milder cases. But that’s the current circumstance we’re in.
‘Two per cent case fatality rate is comparable to the Spanish Flu pandemic in 1918 so it is a significant concern globally.’
How does the virus spread?
The illness can spread between people just through coughs and sneezes, making it an extremely contagious infection. And it may also spread even before someone has symptoms.
It is believed to travel in the saliva and even through water in the eyes, therefore close contact, kissing, and sharing cutlery or utensils are all risky. It can also live on surfaces, such as plastic and steel, for up to 72 hours, meaning people can catch it by touching contaminated surfaces.
Originally, people were thought to be catching it from a live animal market in Wuhan city. But cases soon began to emerge in people who had never been there, which forced medics to realise it was spreading from person to person.
What does the virus do to you? What are the symptoms?
Once someone has caught the COVID-19 virus it may take between two and 14 days, or even longer, for them to show any symptoms – but they may still be contagious during this time.
If and when they do become ill, typical signs include a runny nose, a cough, sore throat and a fever (high temperature). The vast majority of patients will recover from these without any issues, and many will need no medical help at all.
In a small group of patients, who seem mainly to be the elderly or those with long-term illnesses, it can lead to pneumonia. Pneumonia is an infection in which the insides of the lungs swell up and fill with fluid. It makes it increasingly difficult to breathe and, if left untreated, can be fatal and suffocate people.
Figures are showing that young children do not seem to be particularly badly affected by the virus, which they say is peculiar considering their susceptibility to flu, but it is not clear why.
What have genetic tests revealed about the virus?
Scientists in China have recorded the genetic sequences of around 19 strains of the virus and released them to experts working around the world.
This allows others to study them, develop tests and potentially look into treating the illness they cause.
Examinations have revealed the coronavirus did not change much – changing is known as mutating – much during the early stages of its spread.
However, the director-general of China’s Center for Disease Control and Prevention, Gao Fu, said the virus was mutating and adapting as it spread through people.
This means efforts to study the virus and to potentially control it may be made extra difficult because the virus might look different every time scientists analyse it.
More study may be able to reveal whether the virus first infected a small number of people then change and spread from them, or whether there were various versions of the virus coming from animals which have developed separately.
How dangerous is the virus?
The virus has a death rate of around two per cent. This is a similar death rate to the Spanish Flu outbreak which, in 1918, went on to kill around 50million people.
Experts have been conflicted since the beginning of the outbreak about whether the true number of people who are infected is significantly higher than the official numbers of recorded cases. Some people are expected to have such mild symptoms that they never even realise they are ill unless they’re tested, so only the more serious cases get discovered, making the death toll seem higher than it really is.
However, an investigation into government surveillance in China said it had found no reason to believe this was true.
Dr Bruce Aylward, a World Health Organization official who went on a mission to China, said there was no evidence that figures were only showing the tip of the iceberg, and said recording appeared to be accurate, Stat News reported.
Can the virus be cured?
The COVID-19 virus cannot be cured and it is proving difficult to contain.
Antibiotics do not work against viruses, so they are out of the question. Antiviral drugs can work, but the process of understanding a virus then developing and producing drugs to treat it would take years and huge amounts of money.
No vaccine exists for the coronavirus yet and it’s not likely one will be developed in time to be of any use in this outbreak, for similar reasons to the above.
The National Institutes of Health in the US, and Baylor University in Waco, Texas, say they are working on a vaccine based on what they know about coronaviruses in general, using information from the SARS outbreak. But this may take a year or more to develop, according to Pharmaceutical Technology.
Currently, governments and health authorities are working to contain the virus and to care for patients who are sick and stop them infecting other people.
People who catch the illness are being quarantined in hospitals, where their symptoms can be treated and they will be away from the uninfected public.
And airports around the world are putting in place screening measures such as having doctors on-site, taking people’s temperatures to check for fevers and using thermal screening to spot those who might be ill (infection causes a raised temperature).
However, it can take weeks for symptoms to appear, so there is only a small likelihood that patients will be spotted up in an airport.
Is this outbreak an epidemic or a pandemic?
The outbreak was declared a pandemic on March 11. A pandemic is defined by the World Health Organization as the ‘worldwide spread of a new disease’.
Previously, the UN agency said most cases outside of Hubei had been ‘spillover’ from the epicentre, so the disease wasn’t actually spreading actively around the world.
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