I'm an advocate for better ventilation in schools and workplaces. I think it could make a significant difference both in terms of reducing the spread of covid, but also other airborne diseases.

There is an argument which says some of the reduction in R is due to immunity build up through prior infections and as such we may not be able to sustain R<1 indefinitely. Personally though I would prefer to gain immunity through a regular safe and effective vaccine rather than through infection. It is certainly the case that reductions in transmission provided by ventilation would reduce the effective reproduction number relative to what it would be otherwise, taking the edge of the peaks of waves that we might otherwise experience.

I don't believe though that ventilation/filtration is a silver bullet which will end the pandemic on its own. I think it is a tool in a multi-layered protection strategy that we should be implementing which includes vaccination, improved sick pay, mask wearing in some settings, messaging and testing.

We wrote an opinion piece about this in the BMJ earlier this year: https://www.bmj.com/content/376/bmj.o1