Relatives wearing protective gear mourn a man who died due to coronavirus in New Delhi. (Reuters Photo)
More than six months into the pandemic, the coronavirus has infected more than 11 million people worldwide, killing more than 525,000. But despite the increasing toll, scientists still do not have a definitive answer to one of the most fundamental questions about the virus: How deadly is it?
A firm estimate could help governments predict how many deaths would ensue if the virus spread out of control. The figure, usually called the infection fatality rate, could tell health officials what to expect as the pandemic spreads to densely populated nations like Brazil, Nigeria and India.
In even poorer countries, where lethal threats like measles and malaria are constant and where hard budget choices are routine, the number could help officials decide whether to spend more on oxygen concentrators or ventilators, or on measles shots and mosquito nets.
The question became even more complex last month, when the Centers for Disease Control and Prevention released data suggesting that for every documented infection in the United States, there were 10 other cases on average that had gone unrecorded, probably because they were very mild or asymptomatic.
If there are many more asymptomatic infections than once thought, then the virus may be less deadly than it has appeared. But even that calculation is a difficult one.
On Thursday, after the World Health Organization held a two-day online meeting of 1,300 scientists from around the world, the agency’s chief scientist, Dr Soumya Swaminathan, said the consensus for now was that the IFR is about 0.6% — which means that the risk of death is less than 1%.
Although she did not note this, 0.6% of the world’s population is 47 million people, and 0.6% of the US population is 2 million people. The virus remains a major threat.
At present, countries have very different case fatality rates, or CFRs, which measure deaths among patients known to have had Covid-19. In m