Thread by @LeylaDAsadi

This is certainly concerning but I think it's important not to draw conclusions on vaccine effectiveness against delta variant based on this!

First, we have no details on second dose timing or symptoms of the fully vaccinated.

https://twitter.com/globeandmail/status/1403293318419681280

Second, we know the virus is characterized by super spreading events and is highly overdispersed (so 80-90% caused by just 10-20% of people). So cases will be clustered & I suspect it follows that breakthrough infections will also be clustered.

We can't use this 1 small sample size of interconnected cases (with potentially the same source of exposure or same environmental conditions, ie. ventilation) to make VE determination. That's where the UK data is so helpful & far more reliable! For now, it's our best info source.

Third, going forward, we're most likely to find our breakthroughs in health care workers because we'll actually be testing the asymptomatic/double vaccinated there (but likely ignoring them elsewhere).

Finally, we need to really double down on airborne mitigation strategies & rapid tests in these high risk settings. Community rates are much lower now. Public health restrictions are necessary but they cannot be the only tools we reach for.

#covid19ab