Thread by @DiseaseEcology

Is re-instituting lockdowns necessary to stop rapidly rising #COVID19 cases globally?
Answer: No. But we're failing at 2 other approaches, due to poor messaging, human behavior & limited public health capacity.
Deaths & lockdowns are unnecessary but we'll have both again.
Thread

Well-known: if we live our normal lives SARS-CoV-2 spreads exponentially with R=2-3 cases/case every 5-7 days until herd immunity builds up. This leads to huge # of deaths (early UK & US estimates: 500K, 2.2M).
Warning: Things can get bad quickly!
imperial.ac.uk/media/imperial…

Note: total deaths would be less than these early predictions due to interventions we've taken: less overshoot.
(Lockdowns have already paid dividends, but aren't enough!)
See nice work @DeirdreHoll on impact of temporary interventions for flu (Fig 3).
journals.plos.org/ploscompbiol/a…

We're sadly nowhere near herd immunity in 99% of world yet, so returning to normal life will put us back on an exponential trajectory which will overwhelm hospitals and lead to carnage.

https://twitter.com/DrSamirBhatt/status/1271233923599785990

The main strategy used in most countries to stop exponential rise in cases were lockdowns, including closing a large fraction of businesses. Lockdowns were very effective in stopping the exponential rise in cases but devastating to economies and society.

Most countries are now re-opening businesses, which is badly needed, but carries the risk of returning to exponentially rising cases & disaster. Can anything prevent us from having to go through lockdown all over again? For many people & businesses it would spell financial ruin.

Evidence clearly shows there are 2 ways to reduce local transmission, neither of which require lockdown:
1) test-contact trace-isolate (T-CT-I)
2) personal behavior (masks, social distancing including 6'/2m, telework, hygiene)

https://twitter.com/bencowling88/status/1270548060653776897

doi.org/10.1016/S0140-…

The problem is that in most places we aren't doing either well.
Effective T-CT-I requires people get tested very soon after symptom onset. For 3 months limited testing capacity has led to people being told opposite message (stay home unless severly ill).
science.sciencemag.org/content/368/64…

We need huge public health messaging effort to get people to get tested at the first sign of (any) symptoms. Given the wide variety of COVID symptoms this will require ample testing capacity. Testing newly symptomatic people should be top testing priority.
cdc.gov/coronavirus/20…

Next testing priorities:
2) contacts of cases who can't isolate for 14d
3) high risk individuals for onward transmission (those with many close contacts), especially those that could transmit to those at high risk of severe illness. Examples: health care, elder care staff

Many places have insufficient testing capacity, make testing too hard to get, or give results back too slowly to stop spread.
Part of problem is reliance on NP swabs when other methods are better when weighing sensitivity-logistics tradeoff.
e.g. saliva doi.org/10.1101/2020.0…

Pooled testing is another approach that could greatly increase testing capacity at a relatively small cost in terms of sensitivity for infectious people, but has yet to see widespread use.
thelancet.com/journals/lanin…

(Note: capacity gains through pooled testing could, in some settings, enable high frequency testing (i.e. every 1-3d) & isolation that could also limit transmission).

It's shocking to say it, but we are still woefully short on testing capacity, and we are not using it well and we are not combining it with key public messaging to make it effective.
Some places also need more CT. Free training created by @EmilyGurley3: coursera.org/learn/covid-19…

We also need more and better isolation space. Many families live in high density housing and this makes them highly vulnerable to COVID outbreaks. We need safe space for infected people to isolate. Migrant labor & farmworkers are key groups:
latimes.com/california/sto…

Second strategy, changes in personal behavior (inc. masks, social distancing including 6'/2m, telework, hygiene), can also be very effective in reducing transmission. Lots of evidence for this cited above.

Also, see nice summary by @AdamJKucharski of recent article suggesting that human behavior often changes before lockdown to slow transmission:

https://twitter.com/AdamJKucharski/status/1272228227336089600

Unfortunately, human behaviors are now changing in the wrong direction, due to a huge public messaging failure in re-opening businesses. This is a disaster.

Critical point: most business activities can be done safely (exceptions: large indoor gatherings), but need to maintain social distancing in personal lives!
We don't need lockdown to limit transmission but our brains can't seem to separate open businesses & personal behaviors.

As businesses have re-opened there needed to be a clear message: re-opening safely is only possible if people take actions in personal life to limit transmission (masks, 6'/2m, hygiene), including, critically, no close contacts w/ other people in other households.

This messaging did not occur, and people are not taking personal actions to limit transmission. We've translated: businesses open = go back to normal social interactions.
Here's one tiny example, but we have all seen the pictures/videos:

https://twitter.com/lrentzsch13/status/1271802917499142148

Another example: Many very well informed people (including older at-risk people!) are now going to indoor dinner parties at other households. In my county there were many mothers' day gatherings & spreading events at 4 of them led to >50 cases so far.

Some are saying masks and distancing are a hassle & want to have lots of unmasked close contacts again. But these seem like small prices to pay for jobs, economy, activities we all love. Why can't we see this trade-off and choose the far better option?

Conclusion: We must change our personal behavior (in small ways!) & get effective T-CT-I going or else we will have to re-institute lockdowns and lose jobs again, or have huge deaths, or both.
Please, please, let's not go backwards after all we've endured.

Addendum: If I had $100M I'd spend every penny on public messaging to tell people:
1-jobs&economy depend on their actions & small things (masks, distance, hygiene) can make all the difference
2-get tested at earliest onset of any COVID symptoms & isolate until they get results

& I'd beg anyone with influence (athletes, actors, authors, politicians) to release messages/videos demonstrating how much we can do safely (outdoor activities w/ friends 6'/2m apart; eat at restaurants w/ household members; etc.) & how much will be lost if we don't act safely.