Thread by @ProfLWiley

The key US failures around testing back in January-February-March (and continuing like a broken record) were well documented in this piece, which I've gone back to again and again in my writing projects: nytimes.com/2020/03/28/us/…

Yesterday's companion piece documents the key global governance failures around understanding and communicating the role of asymptompatic/presymptomatic spread is a similar tour de force: nytimes.com/2020/06/27/wor…

The two problems - asymptomatic spread and lack of widespread testing - exacerbate each other in ways that have been devastating for the US response.

In the absence of effective vaccines or therapeutics, pandemic responses resort to separating the sick from the well. When infectious individuals can be identified through testing or symptoms, they can be isolated & contacts traced & quarantined, achieving containment.

Many countries successfully used strict, short-term social distancing buy the government time to massively ramp up #TestTraceIsolate to achieve containment (eradication of local transmission) or suppression (very low levels of local transmission).

Achieving containment or suppression is a huge win. Life has returned to something much closer to normal in several parts of the world that were hard hit early on. It requires constant vigilance & resources (& tourism takes a big hit), but worth it to reopen schools, businesses.

In the US, we instituted the same strict social distancing, but because of federal failures to develop fast & effective tests, free up lab capacity, & coordinate supply chains, we didn't use the time bought by strict social distancing implement widespread testing & tracing.

States & locals lifted strict social distancing when it became clear the federal government wasn't going to step up w/ the resources necessary for states to meet stringent gating criteria.

Strict social distancing (stay at home orders, prohibition on all on-site nonessential activity outside the home) only makes sense if it can be used short-term to buy time to implement a modern public health response based on testing & tracing.

W/o a well funded & coordinated national testing strategy, it made sense for state & local governments to shift to a mitigation strategy (slow the spread, flatten the curve) because strict social distancing can't achieve containment/suppression by itself long-term.

Sustainable social distancing measures are needed long-term for mitigation to work. E.g., limits on bars, restaurants & other places large groups tend to gather indoors for an hour +. Several states lifted these restrictions too fast, so now mitigation may be failing in places.

If only symptomatic carriers spread infection, strategies focused on screening travelers, temperature checks & urging people to stay home/mask might have been enough to achieve containment. But it only takes a modest amount of asymptomatic/presymptomatic spread for that to fail.

Given that there's at least some asymptomatic/presymptomatic spread, testing is absolutely critical. But US officials DID NOT prioritize it.