Britannic Herd Immunity and Coronavirus

Epidemiologist William Hanage was more than perplexed by the plan, reflecting in The Guardian:

When I heard about Britain's 'herd immunity' coronavirus plan, I thought it was satire.

Much public policy, foolishly considered and expertly bungled, tends to succumb to satire; having Prime Minister Boris Johnson leading the show provides an even better chance of that happening.

Herd immunity, as a policy, would involve easing off risk and preventive measures, allowing what would effectively be a mass infection, and focusing on recovery from younger members of the populace. Doing so would provide the assurance of immunity to prevent the calamity of another wave come winter. The result is a true peculiarity in health policy: a reluctance to ban mass gatherings, close spaces of public contact and deploy mass quarantine measures.

This, suggests Hanage, is erroneous; it presumes the same rationale used in mass vaccination whereas:

This is an actual pandemic that will make a very large number of people sick, and some of them will actually die. Even though the mortality rate is quite likely quite low, a small fraction of a very large number is still a large number.

On March 12, Johnson's press statement had a certain dressing of alarm. All that seemed to evaporate before a sense of fatalism. Loved ones would be lost. Major public events, he had been told by his experts, would not be banned, because doing so "will have little effect on the spread." To close down schools would cause more harm than good. As for those suffering symptoms that might be coronavirus-related, avoid seeking testing and disturbing the health system. Surf the internet, instead.

Sir Patrick Vallance, Britain's chief scientific adviser, seemed to more than hint that herd immunity as an idea had taken an infectious hold. On Radio Four's Today programme on Friday, he stated that:

Our aim is to try and reduce the peak, broaden the peak, not suppress it completely; also, because the vast majority of people get mild illness, to build up some kind of herd immunity so more people are immune to this disease and we reduce the transmission.

This might have struck those with susceptibility and an assortment of vulnerable conditions as terrifying, though Sir Patrick was insisting that they, too, be protected. Even with a mortality rate of 1%, the death rate would be impressively contained.

That was certainly a scenario entertained by the UK chief medical officer Chris Whitty. A percent of deaths would equate to a loss of 500,000 people in circumstances where 80% of the country would contract the virus. For herd immunity to be achieved, calculated Vallance, "probably about 60%" of people needed infection.

Fuelling this particular approach was a worry shared by Johnson and his advisors that behavioural fatigue might set in. An early imposition of strict restrictions would see a lack of cooperation and caution. Besides, containing the virus initially might work with harsh measures, but not make it go away before the cold spell.

This general view jars with the European response to the outbreak of COVID-19. Owen Matthews, writing in Foreign Policy, noted that:

While continental Europeans were closing schools and putting soldiers on the streets to enforce strict quarantine rules, the British government's official advice to its citizens was, essentially, just to keep calm and carry on.

The Johnson method of governance requires constant cross-checking. Signals are mixed, contradictory and chaotic. Health Secretary Matt Hancock did his little bit of mixed signalling by suggesting UK health policy towards COVID-19 was not quite as Sir Patrick had intended it writing in The Sunday Telegraph:

Herd immunity is not part of it, This is a scientific concept, not a goal or a strategy. Our goal is to protect life from this virus, our strategy is to protect the most vulnerable and the protect the NHS through contain, delay, research and mitigate.

Hancock's hurriedly revised position was assisted, in no small part, by a modelling analysis from immunologists based at the Imperial College of London and the London School of Hygiene and Tropical Medicine, though it was unclear whether he had ever embraced, at least directly, the herd immunity idea. (There is no mention of the term in the coronavirus action plan.) The researchers, in the 9^th report from the WHO Collaborating Centre for Infectious Diseases and Modelling, took a particular interest in comparing potential impacts of COVID-19 to the devastating flu outbreak of 1918.

Two strategies were considered by the research team: suppression, which would involve the reduction of case numbers to low levels or their total elimination; and mitigation, which would not interrupt transmission totally but:

(would) reduce the health impact of an epidemic, akin to the strategy adopted by some US cities in 1918, and by the world more generally in the 1957, 1968, and 2009 influenza pandemics.

In what is an absorbing, if unnerving study, policy makers would have latched onto the conclusion:

that mitigation is unlikely to be feasible without emergency surge capacity limits of the UK and US healthcare systems being exceeded many times over.

The predictions were also rightly sobering. Britain would suffer some 510,000 deaths, and the US 2.2 million were the epidemic to be unmitigated. Using mitigation strategies would see a rough halving: 250,000 deaths in Britain; 1.1-1.2 million in the US.

In the words of the report:

We therefore conclude that suppression is the only viable strategy at the current time.

Cue Prime Minister Johnson's appearance for his No. 10 Downing Street press briefing. In his March 17 statement, he considered COVID-19 to be:

a disease that is so dangerous and so infectious that without drastic measures to check its progress it would overwhelm any health system in the world.

He insisted on steps to avoid unnecessary contact to protect the vulnerable. Capacity for the National Health Service would be increased; public services would be strengthened. Science and research would be boosted. Any measures, as those of a wartime government, should be taken to bolster the economy. Millions of businesses and tens of millions of families needed to be supported. But not a word about bans, closures, testing of the public and strict controls.

The COVID-19 reaction formula still remains a Britannia goes it alone approach though closer to that adopted by the Trump administration. Keep it voluntary; take measures as a matter of good sense. Responses on the European continent remain determinedly autocratic in an effort to flatten the curve of infection. French President Emmanuel Macron has resorted to war metaphors, implementing measures akin to that: mandatory registration of intent to leave homes or face a fine of 38 euros. In Britain, however, Johnson's preference is to prepare for the worst, wash your hands and surf the Internet.