I read the systematic review on mass gatherings that is linked to in the government pandemic plan. This is *not* to say this is what the UK acted on for Covid, but I think it’s helpful to share

The review, broadly, does conclude with a view that bakcs the govt original stance. But it also says something that has been hinted at but not really said explicitly, which is that different types of mass-gatherings have different types of risk attached to them

If we start with mass outdoor gatherings, they might “seed” influenza (introduce a new strain) to an area - but don't seem to lead to high rates of *spread*. Look at how many people were there and look at how small the numbers getting flu are. I was really suprised by this!

Short duration sports events are, according to this evidence, even less likely to spread flu. It might sound counter-intuitive but there really is little evidence even mass-spectator sporting events have much impact on spreading respiratory diseases (at least amongst spectators)

The report authors suggest that the fact that mass events take place outside, in well-spaced and ventilated areas might mitigate the impact. This is important to keep emphasising. The *duration* of the events matters as does the *location*

Contrast that with the attack rate from a conference. Indoors and close contact. Same as in ships and here again we see very high attack rates. *This* is the evidence that is really important

Mass-events like football matches *seem* like an obvious bad idea BUT much of the evidence for flu *and* covid suggest transmission is much more likely inside, with prolonged contact. And that especially means *within* households!

But the other thing I took away from this is that the evidence base is largely weak. It's not a slam dunk one way or the other & the authors are rly more saying "there's not much evidence to support banning events" but that's NOT the same as "evidence says don't ban events"

But if I was a govt minister and I read both the original plan and the evidence review - I think I would have supported what was said at the time. Especially about football. I *might* have thought differently about Cheltnham.... but that's easy to say in hindsight!

Anyway. Like I say. I don't know if the govt used this in its decision. You might read it an come to a different conclusion! But I do think it's helpful