Herd immunity: Why Britain wants 60% of its population to get coronavirus

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Britain's Prime Minister Boris Johnson (centre), Chief Medical Officer for England Chris Whitty (left) and Chief Scientific Adviser Patrick Vallance at a press conference at Downing Street on the government's coronavirus action plan. (Photo: AP)

As Europe was declared the epicentre of the novel coronavirus outbreak last week, Britain announced a different strategy to tackle the situation. Patrick Vallance, the chief scientific adviser to the UK government, said authorities would contain the spread of the virus but would “not suppress it completely”.

Vallance said “a 60 per cent infection rate would help build up a degree of ‘herd immunity’.”

Explained: What is herd immunity?

Herd immunity is when a large number of people are vaccinated against a disease, lowering the chances of others being infected by it. When a sufficient percentage of a population is vaccinated, it slows the spread of disease. It is also referred to as community immunity or herd protection.

On its website, the World Health Organisation (WHO) explains: “Herd protection of the unvaccinated occurs when a sufficient proportion of the group is immune. The decline of disease incidence is greater than the proportion of individuals immunized because vaccination reduces the spread of an infectious agent by reducing the amount and/or duration of pathogen shedding by vaccines, retarding transmission.”

So, what happens in the case of coronavirus where there is no vaccine? The approach would require those exposed to the virus to build natural immunity and stop the human-to-human transmission. This will, it is believed, subsequently halt its spread.

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Britain’s approach to coronavirus

Britain has faced criticism for its soft approach to the coronavirus. The scientific advisor’s statement, too, led to a barrage of criticism from medical professionals and the public.

Vallance, however, defended his statement, saying, “One of the questions when you start something is how are you going to undo it… When you undo it, if you don’t get it right, it bounces back.”

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Attempting to downplay the approach amid criticism, Matt Hancock, Britain’s Secretary of State for Health and Social Care, said Sunday herd immunity was not the government’s policy or goal.

Herd immunity: Can it work?

Dr Richard Horton, editor of The Lancet, called the strategy “a grave error”. Taking to Twitter Saturday, he said: “What troubles me about the UK govt’s response to COVID-19 is its strategic objective. The goal seems to have been herd immunity, delaying urgent action to allow an epidemic to infect large numbers of people. Instead, the goal should have been to save lives. A grave error.”

He also criticised the government for “playing roulette with the public”, and said there was an urgent need to implement social distancing and closure policies.

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Earlier this month, WHO said COVID-19 was “a new virus to which no one has immunity”. “That means more people are susceptible to infection, and some will suffer severe disease,” it added.