Thread. The herd immunity mentality. I agree with Jeremy Farrar that UK might be on track for the largest COVID-19 death toll in Europe. I believe that this will also likely mean that it will suffer the worst economic consequences of the outbreak. https://www.mirror.co.uk/news/politics/breaking-uk-could-worst-hit-21853582

This is despite UK having the natural advantage of being one of the latest countries in Europe to have a large number of cases. This should have given the country more time to prepare. It must be said that one of the reasons it did not is the ambiguous position of its scientists.

This is due to the herd immunity mentality, which still very much exists and matters. Its controversial whether it was ever exactly a "strategy" but anyway noone is directly advocating for that in the public space now, making it hard to address. So I'll focus on the mentality.

To do so, I will respond to the tweets of my colleague and occasional drinking partner from UCL Francois Balloux. I like and respect Francois, just as he does me. But I find his position on this and actually also the mode of argumentation damaging, so I need to respond carefully.

Im going to focus on this tweet https://twitter.com/BallouxFrancois/status/1249269502296100864 which accuses a fellow academic of empty sloganeering. I want to show that actually what Francois is doing is sloganeering.

Francois says: "There is no other realistic way out of #COVID19 to building up 'herd immunity' through vaccination/infection." *This* in my mind is the herd immunity mentality. Its a way of framing the argument.

My alternative framing is: "there is no other realistic way out other than reducing viral transmission to zero". The only benefit of 'herd immunity' is that it makes transmission less common. So my framing encapsulates his.

Herd immunity through infection will never be a way of reducing viral transmission to zero because a proportion of the population will not be infected. It will need to be accompanied by other measures. At most, its just an aid, and an aid that paid for in lives and disability

not to mention economic damage. I am pretty sure that as in 1918, the places that engage in most active viral suppression will also emerge best from this economically. Furthermore, Chinese example suggests that zero herd immunity is necessary if suppression is committed enough.

Obviously, herd immunity through vaccination can be comprehensive and we can all agree that it would be vastly preferable, especially if the vaccine worked. But thats not on the table immediately, so put it aside.

What the herd immunity mentality leads to is dismissing interventions on the grounds of pointlessness or inapplicability. For example in the tweet above he says "testing is pointless in itself". Its true, but it facilitates or improves almost every other worthwhile intervention.

If the strategy is that everyone should wait to become infected and then stay at home until they die or recover, then testing would be pointless. But in hospitals its better to treat COVID-19 patients separately from others, to avoid exposing others to high viral loads.

I have argued that to reduce transmission, it is necessary to separate infected people from susceptible ones, and testing must be at the bedrock of that, whether there is low herd immunity or high. https://twitter.com/DanielFalush/status/1248243912893796353

I often tweet about the interventions used in China that have been successful in reducing transmission. The herd immunity mentality response is "that is not applicable to the West", rather than considering how to make it applicable. https://twitter.com/BallouxFrancois/status/1248265201448816640

Sorry to single you out Francois. I know your intentions are good but the herd immunity mentality is presented as realism, but all too often it just ends up functioning as a justification for accepting defeat. It needs to be firmly rebutted. END.