As Britain has switched from the "containment" to "delay" phase in response to the spread of COVID-19, the Downing Street hopes to create "herd immunity" to the disease instead of taking proactive and drastic countermeasures.
"Herd immunity," also called "community immunity" or "herd protection," technically means a form of indirect protection from infectious disease that occurs when a large part of a population is vaccinated and becomes immune to infections, thereby protecting vulnerable people such as newborns, seniors and those who are too sick to be vaccinated.
Despite encouragement of more social distancing, travel advice against COVID-19 hotspots and a forthcoming ban on mass gatherings, British Prime Minister Boris Johnson said Thursday that he would not close schools when tackling what he described as "the worst public health crisis in a generation."
While these steps fell quite short of what other countries have done, Patrick Vallance, the British government's chief scientific adviser, said it is hoped that the approach can build up "herd immunity" to the disease.
In this case, millions of British people, around 60 percent, would need to get ill and become immune, so as to lessen the impact of what is likely to become an "annual virus," Vallance explained.
However, some professionals emphasized that the "herd immunity" strategy only works if most people in the population are vaccinated; and as a tactic for fighting a pandemic without any vaccine, it is novel and somewhat alarming.
The strategy has sparked debates, mostly questions and criticism, among medical professionals.
Margaret Harris, a leading official with the World Health Organization (WHO), on Saturday questioned the idea of developing "herd immunity" against the coronavirus in an interview with BBC Radio 4.
"We don't know enough about the science of this virus, it hasn't been in our population long enough for us to know what it does in immunological terms," she said. "We can talk theories, but at the moment we are really facing a situation where we have got to look at action." Rebuking the British government for its slow response to the COVID-19 outbreak, Richard Horton, editor of the prominent British medical journal The Lancet, tweeted that the government is "playing roulette with the public."
In an open letter written to the Downing Street, 229 scientists from British universities said that the current strategy will put the National Health Service under additional stress and "risk many more lives than necessary."
The British Department of Health and Social Care has defended Vallance against the criticism, saying that his comments were misinterpreted.
Meanwhile, some people in the Whitehall's "nudge unit" have voiced support for the "herd immunity" strategy, including David Halpern, chief executive of the government-owned Behavioral Insights Team and a member of the Scientific Advisory Group for Emergencies.
"There's going to be a point, assuming the epidemic flows and grows, as we think it probably will do, where you'll want to cocoon, you'll want to protect those at-risk groups, so that they basically don't catch the disease, and by the time they come out of their cocooning, herd immunity's been achieved in the rest of the population," Halpern told BBC News.
The number of confirmed COVID-19 cases in Britain reached 1,372 as of Sunday, an increase of 232 over the last 24 hours, and 14 more people died, bringing the total number of deaths to 35, according to the health department.