'Herd immunity' is a phrase normally used when large numbers of children have been vaccinated against a disease like measles, reducing the chances that others will get it. As a tactic in fighting a pandemic for which there is no vaccine, it is novel and because it is untested and alarming. It relies on people getting the coronavirus and becoming immune as a result. However, controlling the progress of the disease by allowing the population to build up immunity in this way could increase the risk to the most vulnerable and the largest number of these is old men and women with underlying health problems. This approach stands in stark contrast to the widespread testing, tracking down the contacts of every case and isolating them, that many other countries in Asia and Europe have chosen to do.
According to
Sir Patrick Vallance, the Government’s Chief Scientific Adviser, to reach herd immunity, about 60% of the population of Britain would need to get ill and become immune. The calculations behind this are that for every 2.5 people you sneeze on, you want 1.5 to already be immune. Herd immunity for coronavirus, then, is 1.5 divided by 2.5, or 60%. If indeed it is the Government’s belief that the coronavirus cannot be stopped until we gain herd immunity, then that seems, at least superficially, to be an astonishing admission : an acceptance that more than 40 million people will get the disease. With even a 1% fatality rate, that is 400,000 deaths.
Scientists who understand the strategy are anxious.
Martin Hibberd, Professor of Emerging Infectious Disease at the London School of Hygiene & Tropical Medicine said :
“I do worry that making plans that assume such a large proportion of the population will become infected, and hopefully recovered and immune, may not be the very best that we can do.”
Professor
Anthony Costello, a paediatrician and former World Health Organization Director, said that the British Government was out of kilter with other countries in looking to herd immunity and quoted the Director General of WHO, Dr Tedros Adhanom Ghebreyesus, who has said :
“The idea that countries should shift from containment to mitigation is wrong and dangerous.” Costello also said the Herd Immunity might not even last :
“Does coronavirus cause strong herd immunity or is it like flu where new strains emerge each year needing repeat vaccines? We have much to learn about Co-V immune responses.” Vaccines, he said, were a much safer way of bringing it about.
Richard Horton, Editor of 'The Lancet' is the most prominent medical critic and citing desperate pleas from Italian doctors has said :
“The UK Government — Matt Hancock and Boris Johnson — claim they are following the science. That is not true. The evidence is clear.
The Government is playing roulette with the public. This is a major error. The UK is on the edge of an avoidable calamity.
In addition to deaths preventable by more aggressive Government action, it will be health workers who absorb the brunt of Government complacency. I am not being alarmist. What is happening in Italy is real. Our government is not preparing us for that reality. We need immediate and assertive social distancing and closure policies. We need to prepare the NHS.”
One possible method of avoiding sacrificing Britain's old men and women on the altar of Herd Immunity may be seen in the fact that the 60% who need to get it, need not be a random sample of the population. Instead, with sensible measures and
“cocooning” of those most at risk, it may be possible to protect the old and sick, even as the virus sweeps through the healthy. In other words, the prescription for old men and women in Britain is :
REMAIN COCOONED IN YOUR HOMES FOR THE NEXT 3 - 4 MONTHS AND VENTURE OUT AT YOU PERIL
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