WHO: Allowing Spread of Virus to Achieve Herd Immunity is “Unethical”

He also stressed the many long-term health problems of infection, which researchers are only just beginning to understand.

And he pointed out that it has been estimated that less than 10 percent of the population in most countries are believed to have contracted the disease.

"The vast majority of people in most countries remain susceptible to this virus," he said.

"Letting the virus circulate unchecked therefore means allowing unnecessary infections, suffering and death."

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Overall, it is estimated that 0.6 percent of people who contract Covid-19 die from the disease, Maria Van Kerkhove, WHO's technical lead on the virus, told Monday's briefing.

"That may not sound like a lot," she acknowledged, stressing though that it "is a lot higher than (for) influenza".

She also pointed out that "the infection fatality ratio increases dramatically with age."

While the elderly and people with underlying health conditions are clearly most likely to fall seriously ill from Covid-19, Tedros stressed that they are not the only ones at risk.

"People of all ages have died," he said.

The UN agency also voiced optimism at the speed at which Covid-19 vaccines against the virus are being developed, with 40 vaccine candidates in clinical trials, including 10 in late-stage Phase 3 trials.

Read also: Clinical Trials of a Coronavirus Vaccine Back on Track

US President Trump has repeatedly promised that a Covid-19 vaccine will be ready before next month's US elections.

But WHO chief scientist Soumya Swaminathan said the vaccines in late-stage trials were not expected to produce sufficient data to request regulatory approval until December, at "the earliest".

"Into the early part of 2021, we expect a number of trials to start providing data for regulators to look at," she said.