Facts Vs. Fears: Five Things To Help Weigh Your Coronavirus Risk
The news about the novel coronavirus in China grows more urgent daily. The number of related deaths is now greater than 1,300, while tens of thousands of people have been infected — most of them in China. People returning to the U.S. from China are quarantined for 14 days. It can be frightening to think about the threat, but public health officials in this country constantly remind people that the risk of the disease here is low.
Still, scientists have more questions than answers about important issues surrounding the coronavirus, now officially named COVID-19. Here’s some help in understanding the unknowns and evaluating the risks.
More than 1,300 people have died from this virus since December. That sounds pretty scary. Should I be worried?
All but two of those fatalities occurred in China, where the virus emerged. That country has reported the lion’s share of cases, said Dr. William Schaffner, a professor of preventive medicine, health policy and infectious diseases at Vanderbilt University Medical Center.
The 15 Americans identified so far with the disease had recently been in China or had close contact with someone who became infected in China. In addition, public health officials report that many of the U.S. cases have been relatively mild infections.
The number of deaths in China is startling, but remember, even a virus with a low fatality rate can kill many people if the number of infections is large. For example, influenza kills 0.14% of infected patients, said Dr. Peter Hotez, a professor of pediatrics, molecular virology and microbiology at Baylor College of Medicine in Houston. But because the flu is so common — infecting up to 45 million Americans a season — deaths could climb as high as 61,000 people each flu season just in the U.S., according to the Centers for Disease Control and Prevention.
But the statistics coming out of China are also suspect, and experts don’t yet know how to evaluate them. For example, Chinese officials Thursday suddenly changed their criteria for confirming the disease and added more than 15,000 cases to the patient tally — after two days of reporting a downturn in the number of people affected.
To be sure, it is often difficult to get a good assessment of cases while using most of your public health resources to fight an outbreak.
The number of coronavirus cases may be much higher than China is reporting, said Lawrence Gostin, director of the World Health Organization Collaborating Center on Public Health Law & Human Rights. That may not be a deliberate effort to downplay the outbreak but could signal problems “with China’s capacity for testing and surveillance,” he said. “They are just not picking up all the cases and deaths. An even greater problem is that there is no independent verification.”
The World Health Organization “is relying on data from China and has no ability at present to independently verify those data,” Gostin said. That could change, he added, if WHO experts are allowed into the center of the outbreak, the city of Wuhan in Hubei province. “But I have significant concerns that even then [WHO] won’t have access to full information,” he said.
What is the mortality rate from this virus?
News reports and health officials have reported widely varied estimates of death rates for this outbreak. Schaffner cautions that calculating those numbers in a fast-moving outbreak is difficult.
Mortality rates are determined by dividing the number of deaths by the number of infections. While counting the dead is generally straightforward, it can be impossible to find the total number of infections because some people with the virus develop few noticeable symptoms. Since COVID-19 is new, doctors don’t know what percentage of infections fall into this category, Schaffner said.
It’s not surprising that mortality rates for the coronavirus vary dramatically, based on where diagnoses were made, Schaffner said. For example, a report Monday from the Imperial College of London found a mortality rate of 18% for cases detected in Hubei, where only patients with unusual pneumonia or severe breathing problems were being tested for the virus. Outside China, health officials test anyone with a cough and fever who has visited Hubei — a much larger number — producing a mortality rate of 1.2% to 5.6%.