Their official stance before that was rigorous test, isolate, and trace, which was not done seriously anywhere outside China.
In my mind it was ‘mask before the apparition of symptoms’, and I realise that my wording was not ideal in the context.
I am fairly certain that the US government reversed itself on masks before the WHO did (Wikipedia says WHO changed its advice in June).
Did it have to do with a lack of evidence, or was it a cynical ploy to preserve mask stocks for medical professionals? I recall it being the latter: https://www.nytimes.com/2020/03/17/opinion/coronavirus-face-...
I feel like the reporting from the WHO was deliberately sub-par for political reasons. For example the vacillating on masks - everyone knew that masks helped, but the WHO tried to be on the fence about it because some countries were experiencing shortages. Another example of the WHO playing politics was when they neglected to publish the advice not to trust folk remedies, since that would have gone against a Chinese government campaign to try softly promote TCM, perhaps as a form of psychological comfort to the hundreds of millions stuck in lockdown.
Living through corona has helped me to realize that successful public health policy isn't just about giving everyone the raw facts, it's also about managing people's morale and trying to influence their behavior through propaganda. I think the WHO tried to do this, but it wasn't universally successful.