The UK’s initial ‘herd immunity’ approach to COVID-19 has its origins in “animal husbandry” and is a concept that can lead to a “brutal arithmetic” which does not focus on “people and life and suffering” if applied to humans, an executive director of the World Health Organisation has said.
Dr Mike Ryan, who works on the WHO’s health emergencies programme and leads the team responsible for the international containment and treatment of COVID-19, told a press briefing today that he was concerned about the use of the term ‘herd immunity’ in relation to the Coronavirus because it usually applies to vaccination not natural infection.
“Humans are not herds and, as such, the concept of herd immunity is generally reserved for calculating how many people would need to be vaccinated in a population in order to generate that same effect. So I think we need to be really careful when we use terms in this way around natural infections in humans. It can lead to very brutal arithmetic which does not put people and life and suffering at the centre of that equation.”
“Herd immunity is a term taken sometimes from veterinary epidemiology where people are concerned in animal husbandry with the overall health of the herd,” he said. “An individual animal in that sense doesn’t matter from the perspective of the brutal economics of [that] decision-making.
Letting a disease such as COVID-19 to move through a population in order to allow people to become immune to it – at the cost of vulnerable people dying – is “a really dangerous calculation”, Dr Ryan added.
His comments followed those of Dr Maria Van Kerkhove, also based in the WHO’s health emergencies programme, who said that studies conducted in Europe, the US and Asia have shown a “consistent pattern so far that a low proportion of people have these antibodies” for COVID-19. In some of the studies, there is evidence of just one to 10% of people having antibodies for the virus.
“That is important because… [of] herd immunity, which is normally a phrase that’s used when you think about vaccination, and you think what amount of the population needs to have an immunity to be able to protect the rest of the population and we don’t know exactly what that level needs to be in terms of COVID-19,” she said, adding that it needs to be much higher than suggested so far by studies. She concluded that a large degree of the population therefore remains susceptible to the Coronavirus.
An approach of ‘herd immunity’ was first put into the public domain in the UK by the Prime Minister himself, when he alluded to it on 5 March on This Morning. Asked whether delaying the Coronavirus was about ‘flattening the curve’ of the pandemic, he said: “That’s where a lot of debate has been and one of the theories is that perhaps you could take it on the chin, take it all in one go and allow the disease, as it were, to move through the population, without taking as many draconian measures… I think it would be better if we take all the measures that we can now to stop the peak of the disease.”
The following week, the Government’s Chief Scientific Advisor Sir Patrick Vallance told Sky News: “We think this virus is likely to be one that comes year on year, becomes like a seasonal virus. Communities will become immune to it and that’s going to be an important part of controlling this longer term. About 60% is the sort of figure you need to get herd immunity.”
Health Secretary Matt Hancock has subsequently said that ‘herd immunity’ was never a “goal and strategy” of the Government, but questions remain about why Johnson’s administration – unlike in most other countries around the world – did not introduce early social distancing and lockdown measures when it knew that COVID-19 was spreading; and why it has continued a lax approach to mass testing, contact tracing, quarantine, the procurement of personal protective equipment, the closing of borders and strict public health messaging.