Although the infection fatality ratio – or, how many people who are infected with Covid-19 die from it – sounds low, it is actually “quite high,” especially when compared with other pandemics, according to officials at the World Health Organization.
There are different ways that mortality can be calculated, and at this point, many groups are looking at the infection fatality ratio – which is the number of deaths among all the people who have been infected, Maria Van Kerkhove, WHO’s technical lead for coronavirus response, said at a press briefing in Geneva on Monday.
“Right now, we don’t know how many people have been infected because there are challenges with surveillance in detecting every single one of the cases, and certainly there are many unrecognized cases,” Van Kerkhove said.
While there are challenges, Van Kerkhove said that some studies have estimated the infection fatality ratio at 0.6%. That “may not sound like a lot, but it is quite high,” she said.
We know that mortality increase with age, and among people with underlying conditions, she said.
“We must do everything that we can to prevent ourselves, and those individuals, from getting infected,” Van Kerkhove said.
Dr. Mike Ryan, executive director of WHO’s Health Emergencies Programme, put some perspective on the 0.6% infection mortality rate, saying “that 0.6% is just over 1 in 200 people infected, potentially dying.”
He did say that this was hugely skewed by age, with the risk being much higher in older ages groups.
Ryan compared this number with the 2009 H1N1 pandemic, where “it was more like 1 in 10,000 or 1 in 100,000,” he said. “But when you think 1 in 200 versus 1 in 10,000 or 1 in 100,000, you get a sense of just how more deadly this virus is in communities.”
This points to the fact, he said, that everyone should try to avoid getting infected.
“When we talk about death and fatality, that is the outcome of an infection, and an infection is the outcome of an exposure” Ryan said. “If people are not exposed to the virus, they cannot be infected. If they’re not infected, they cannot infect anyone else, and they don’t die.”
“I hope if we focus on that exposure reduction, infection reduction, then we will be talking about mortality going down,” he said.