There is unlikely to be any long-term herd immunity to this virus. Much like other coronaviruses, there is growing evidence that the immune system does not form a permanent memory of SARS2. Reinfections can be as bad as or worse than the first infection. A laissez-faire approach could at best mean a "flu-like" annual cycle of a very large number of infections, with a virus that is less well tolerated and has a wider range of severe symptoms than influenza, not-uncommonly causing long-lasting effects.
From a medical perspective I think three key considerations are:
- Minimising the number of symptomatic infections, because they can lead to disability even in healthy young people
- Keeping the number of severe infections at one time below the number of available hospital beds and doses of antiviral drugs
- Avoiding a sustained exponential rate of transmission of the virus, as that will inevitably overwhelm healthcare and emergency infrastructure
I think there is a fourth consideration that is key to the implementation of public health policy in general:
- Ensuring that there is no personal financial impact to an individual following medical guidance
If the virus is spreading at an exponential rate, then new infections can be drastically decreased by asking everyone who is not a key worker to remain home. This should be done in order to protect existing infrastructure (such as testing centres or intensive care units) and to allow a period in which the government can intervene to build or expand further relevant infrastructure. I believe it's important for compliance - as well as clearly being the compassionate thing to do - that anyone financially impacted by remaining home is fully supported.
If the trajectory of new infections is logistically sustainable (i.e. not exponentially increasing), then policy should focus on minimising and controlling it while allowing people as much freedom to go about their lives as possible. There are four core approaches we can use: 1. Identifying remote working and learning implementations and pursuing them aggressively; 2. Ubiquitous mask usage; 3. Testing of symptomatic people, with isolation if positive; 4. Tracing of the contacts of infected people, who can be isolated.
Remote working and learning are important to reduce the number of people travelling around the country, both daily on public transport which is a vector for infection, and the admixture of populations such as during the seasonal student migrations. Office workers were explicitly encouraged back to the office, and schools and universities were encouraged not to pursue remote solutions for the September term, which was all counterproductive. By encouraging workers, students, and schoolchildren who are able to do so (they have a good laptop, their work/lessons are not "practical", and so on) to work from home, you can free up capacity for safe travel and socially distanced offices / lecture halls / classrooms for those who really need to go in.
Mask usage is particularly important because background exposure to very low viral loads seems to confer immunity. That is, if you are frequently exposed to a very small amount of virus - such as the reduced load that gets through a mask - your immune system has a chance to develop recognition of the virus without having to deal with a full infection. At the moment, compliance with advice on masks is relatively low. The government needs to conduct a large-scale public education campaign and then enforce compliance. Alternative kinds of covering should be used by people distressed by wearing a mask, but no-one should be fully exempt from wearing a covering (alternatives include e.g. snoods, face shields).
At the moment, it seems clear that we have not had sufficient leadership or investment in testing or tracing, and this infrastructure needs to be rapidly expanded. The contracts should clearly not remain with private sector companies who are unable or unwilling to fulfil them.
Finally, because large groups of drunk people are not known for their compliance with sometimes complex medical guidance, I believe nightclubs, bars, and pubs should be closed - or takeaway-only if they serve food - for the foreseeable future.