How deadly is the coronavirus? It may take months to find out

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The World Health Organization announced this week the COVID-19 fatality rate is higher than previously believed, leading to concerns about the potential implications as the new virus makes its way around the world.

But public health experts say the fatality rate is merely a snapshot in time and that there’s good reason to believe the actual figure is likely lower.

On Tuesday, the World Health Organization director general Tedros Adhanom Ghebreyesus said the current fatality rate for COVID-19, the name of the disease caused by the new coronavirus, is 3.4 per cent. Previous estimates pegged the death rate between 1 per cent and 2 per cent.

The WHO noted that the virus is more deadly than the flu and that countries need to be prepared to respond. While the majority of people who get infected with the new virus recover well, about 20 per cent experience a severe illness, with a subset of those falling critically ill and dying.

People over 65 with existing health problems tend to be more susceptible to severe illness and death linked to COVID-19. There is not yet a vaccine or cure for the disease.

David Fisman, an epidemiologist at the University of Toronto’s Dalla Lana School of Public Health, said there are a number of reasons why the death rate is rising and that it likely doesn’t reflect the actual figure.

One aspect is that countries likely aren’t counting the total number of cases they have, Dr. Fisman said. Many people with COVID-19 report having mild symptoms, meaning that a number of people who are infected likely aren’t going to hospitals or being tested for the illness. That means the total number of cases around the world is likely higher than reports suggest, which would make the overall fatality rate lower.

Second, countries such as Iran and Italy had major outbreaks of COVID-19 before health officials realized it. In those countries, the epidemics only came to light because seriously ill people started showing up in hospitals and dying. But the actual number of cases in those countries is probably higher than reported, Dr. Fisman said.

Outbreaks at hospitals and among the elderly are also going to inflate the death rate, Dr. Fisman said. Earlier this week, U.S. officials realized that patients at a long-term care facility in the Seattle area had COVID-19 and that several had died as a result. Those clusters of outbreaks among highly vulnerable people could inflate the death rate, he said.

Another reason is that it typically takes weeks for patients to die of COVID-19. So some severely sick patients in China may have been hospitalized for weeks, but are only dying now. The outbreak in China has been going on for months, so as more patients there die, it can make it appear as though the overall fatality rate of COVID-19 is higher than it is. But in several months, the true figure will become much clearer, as countries start to track cases more diligently and experts are able to gather more data.

The challenge that continues to face health care officials is the fact COVID-19 is so new. Researchers around the world are continuing to track data and trying to learn as much as possible about the transmissibility of the illness. But in the meantime, many experts say people should remain calm and avoid sources of misinformation, such as social media.

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