“Guided by the science”  (Owl has been discussing this with trusted friends knowledgeable in health matters). Here is a digest of that discussion.

Owl understands that computer models are being used to test and guide the most appropriate strategy to counter Coronavirus. Since this is a novel virus there is much we don’t know. These models, therefore, have to be built on a raft of assumptions. The truly scientific approach would be to make these assumptions openly available and to use the models to test the sensitivity of strategy formulation against the likely range of assumption uncertainty. This should highlight the critical assumptions, allowing debate to be focussed on the issues that really matter. Hopefully, robust strategies can be found that are sound against a range of uncertainties. Where this is not possible, decisions becomes a matter for political decision and judgement. Where the scientist has to be careful is when he/she has an underlying “agenda”. 

Yesterday (Saturday 14 March) both the Times and Guardian carried a number of letters from eminent scientists, clinicians  and epidemiologists calling for publication of these assumptions. There are official admissions (repeated on every BBC news bulletin) that the number of cases might be as high as 10,000. To have that many undetected i.e. mild or asymptomatic cases can surely only come from a radically different set of assumptions? On what evidence is this based and why is it being said?

The UK appears to be following a very different strategy to other nations. This short article discusses the central Herd immunity strategy.

Sarah Boseley  www.theguardian.com

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 some say alarming.

It relies on people getting the disease – in this case Covid-19 – and becoming immune as a result. Generally it is thought that those who recover will be immune, at least for now, so they won’t get it twice.

But allowing the population to build up immunity in this way – rather than through widespread testing, tracking down the contacts of every case and isolating them, as many other countries in Asia and Europe have chosen to do – could increase the risk to the most vulnerable: older people with underlying health problems.

To reach herd immunity, about 60% of the population would need to get ill and become immune, according to Sir Patrick Vallance, the government’s chief scientific adviser. Though it could need as much as 70% or more. Even scientists who understand the strategy are anxious. “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,” said Martin Hibberd, professor of emerging infectious disease at the London School of Hygiene & Tropical Medicine.

“Another strategy might be to try to contain [it] longer and perhaps long enough for a therapy to emerge that might allow some kind of treatment. This seems to be the strategy of countries such as Singapore. While this containment approach is clearly difficult (and may be impossible for many countries), it does seem a worthy goal; and those countries that can should aim to do.”

The government’s “nudge unit” seems to favour this strategy. Dr David Halpern, a psychologist who heads the Behavioural Insights Team, said on BBC News: “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.”

But Anthony Costello, a paediatrician and former World Health Organization director, said that the UK government was out of kilter with other countries in looking to herd immunity as the answer. It could conflict with WHO policy, he said in a series of Twitter posts, which is to contain the virus by tracking and tracing all cases. He quoted Dr Tedros Adhanom Ghebreyesus, the WHO director general, who said: “The idea that countries should shift from containment to mitigation is wrong and dangerous.”

Herd immunity might not even last, Costello said. “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.

It need not be this way

Gordon Brown, based on his experience of the banking crisis, writes: (full text on seperate post)

It need not be this way but one of the most disastrous weeks in the history of global medicine and global economics has ended with country after country retreating into their national silos. They are fighting their own individual battles against coronavirus and in their own way.

Each country has, of course, its own distinctive health systems that it relies on, rightly values its own medical experts and the disease is at a different stage in each. But why is there, as yet, no internationally coordinated medical project – equivalent to the wartime Manhattan Project – mobilising all available global resources to discover a coronavirus vaccine and to fast-track a cure?

Why, as the disease engulfs more than 100 countries, has there been no consistent, coordinated global approach not just to tracking, testing and travel but to openly learning from each other about the relative merits of quarantine and social distancing? And why, when a world recession now threatens, is there not yet an attempt at a combined effort on the part of governments and central banks to deliver a global economic response?

Instead, ours is a divided, leaderless world and we are all suffering from the tendency to go it alone: an initial cover-up in Wuhan; China’s delayed reporting to the international community; the World Health Organization (WHO) meekly agreeing that the crisis was “moderate”; and even when on 30 January it apologised and declared an international emergency, still the world continued to receive confused travel advice.