Policy makers are taking full account of the 16 March paper from the Imperial College Covid-19 Response Team – Impact of non-pharmaceutical interventions (NPIs) to reduce Covid-19 mortality and healthcare demand. They are right to do so. There are no certainties in epidemiology, but no team in the world is better qualified to advise how to slow or blunt the spread of the virus. The team there includes a WHO Collaborating Centre for Infectious Disease Modelling, and the Medical Research Council Centre for Global Infectious Disease Analysis. Read the report yourself. We don't need commentators to inform our thinking.
Look at the science and look at the evidence. Models are models and theirs will be increasingly informed as the pandemic progresses. The authors acknowledge that there are significant uncertainties as things stand. Their message is clear: they are saying that in a mitigated epidemic hundreds of thousands of deaths might occur worldwide; there have been around 10,000 at the time of writing. But mitigation is not the option being pursued; suppression strategies are being adopted, aimed at reversing spread of the epidemic.
Mitigation seeks only to slow transmission. It won't stop the epidemic. Suppression, on the other hand, aims to reduce case numbers to low levels through social distancing and home quarantine. The scientists from Imperial said that these measures may need to be supplemented by school and college closures (as has now happened), though they acknowledge these will also have negative effects. No one is happy with the situation. But the only reasonable conclusion is that the government has looked at the facts and the state of our current knowledge and has responded with a sensible and balanced policy.
The key reference point here is what they call the reproduction number (R), shorthand for the number of people to whom each infected person will transmit the virus. Reduce it below one and the number of cases will start to fall. Only suppression strategies can achieve this. The vast majority of people who contract Covid-19 will make an uneventful recovery and can be assumed to be immune to reinfection, at least in the short term. Evidence from the Flu-Watch cohort studies suggests that re-infections with seasonal circulating coronavirus is highly unlikely in the same or the following season.
But hundreds of thousands of people in our society, especially those with existing illnesses, are at risk of losing their lives prematurely. That's why we must act collectively in our own and in their interests by listening carefully to and sharing the evidence-based strategy being advocated by government.
