How do we “unscare” people?
It’s easy to scare people. It’s harder to “unscare” them (in fact unscare is not a word). Customers will need more than permission to return to restaurants and other businesses that were closed because of a virus they know is still circulating. In a Gallup poll, only 20% said they would return back to normal activities immediately after restrictions are lifted.
The goal of this post is to encourage Austin to implement a system that makes it practical to test everyone each day when they arrive at work or school. This new approach to testing requires recognizing that this is a wartime effort, setting aside current protocols, and combining a few ideas in a way that has not been done before. Experts will say this is not possible, but that’s what experts say when something has never been done before.
After September 11th, 2001, people were afraid to fly. By November 19th, the Transportation Security Administration had been established. TSA had two functions. First, make us safer when we fly. Second, make us feel safer when we fly. Both goals were met with new security measures we could see — TSA members in uniforms, new scanning equipment, removing laptops and shoes.
Customers complained about the added friction, but they accepted it as necessary — and started flying again. This pandemic is directly impacting the lives of more people than 9/11. We don’t need to create a new federal agency, but people need to see real changes that give them a reason to feel safe.
The impact on some sectors has been especially severe:
Austin hotel rooms booked — down 97%:
Restaurant revenue is down 73% — despite the ability to offer takeout:
Austin’s unemployment rate went from 2.6% to 25% (national rate estimated at 32% by Federal Reserve):
We closed things in March because a rapidly spreading and deadly virus was going to overwhelm our hospitals. We needed to “flatten the curve” the only way we could at the time — by quarantining most of the population. We should take a moment and celebrate the fact that we made a tough choice and achieved this goal together. We flattened the curve.
We knew there would be a price to achieving this goal and buying ourselves time to figure out what to do next. As we look towards reopening, we need a new goal that balances infection rate and unemployment rate:
Get R0 under 1 — without quarantining most of the population.
Pronounced “R naught” and also referred to as the reproduction number, R0 is a measure of how contagious a disease is. An R0 of 2.5 means one infected person infects 2.5 others. We all learned about “flattening the curve” to avoid the spike in demand from a virus with exponential growth. But we rarely hear the media talking about “R naught” or a reproduction rate under 1.
SARS-CoV-2 (the novel coronavirus that causes COVID-19) has an estimated R0 between 2 and 3 — which is considered high. Seasonal flu is estimated to have an R0 of 1.3. An R0 below 1 means each infected person infects less than 1 other person. Let’s assume that using masks and staying 6 feet apart help reduce R0 to 2.0. This is what an R0 of 2.0 looks like compared to an R0 of .8:
An R0 under 1 means the virus dies out on its own — with no cure and no vaccine.
After 5 cycles, an R0 of 2.0 leaves 39 times as many people infected than an R0 of .8. After 10 cycles, an R0 of 2.0 produces 3,814 times more infected people. This is why most of the population was asked to stay home. This was the only way to stop the spread and get R0 from 2.5 to under 1. We don’t need a perfect system that stops all spreading of the virus. If each infected person infects less than one other person, the virus will die out on its own.
So, how do we achieve our next goal — R0 under 1 without quarantining most of the population and creating Great Depression levels of unemployment?
Test infected people before they infect other people.
We currently focus testing efforts on individual patients — after they are sick enough to be tested, and after they have already infected other people for about a week. In addition to these conventional individual tests, we need to add population-scale testing — before infected people infect others.
Population scale testing will be impossible if we simply try to scale up conventional collection methods and testing systems. But population-scale testing does not have to adhere to the same rigid testing protocols.
During a war, if someone is wounded and bleeding to death, a soldier might turn their t-shirt into a tourniquet. A t-shirt is not the best tourniquet, but it’s good enough. If we think of this as a wartime effort and set aside conventional thinking and protocols, what are the “t-shirts into tourniquets” options that are good enough to enable a massive increase in testing capacity?
Thermometers, spit, pools — and tracing.
Thermometers
Fever screening is not a test for the virus itself but it is a test. It is possible to transmit this virus while asymptomatic, but most transmission (56%) happens after patients are symptomatic as viral shedding peaks close to when symptoms appear — and the #1 symptom is fever. According to this study, 98% of hospitalized COVID-19 patients in Wuhan (136/138) had a fever.
Even if fever screening is only 30% effective, we need to think of this as just one layer in a filtration system. City-scale water filtration systems have multiple layers. The first filter removes rocks. Fever screening will not catch everyone, but it will catch the rocks — and someone walking around the grocery store with a 102-degree fever during a pandemic is a rock.
TSA uses metal detectors even though all threats are not made of metal and metal detectors on their own would not ensure our safety. TSA also thinks in terms of layers — 20 layers:
Fever testing is visible, easy to do, and inexpensive. It may act as a deterrent that encourages people who know they are sick to stay home. Even if it’s only partially effective, fever testing is an important layer in the system that will help reduce R0.
Spit — Saliva instead of nasopharyngeal swabs for molecular / PCR tests
Molecular testing using PCR (polymerase chain reaction) takes a tiny amount of virus and creates more than a billion copies:
The process is more complicated than this and takes dozens of cycles like the ones shown above, but what matters is that molecular testing (which almost always means PCR testing) identifies the actual virus in a sample. The standard for collecting these samples is the nasopharyngeal swab.
Nasal swabs are painful for patients, expose healthcare workers to infection while collecting the sample, and are in short supply.
A saliva sample would be the least invasive option and could be done more frequently. When asked in early March if saliva was an option, multiple doctors said that saliva is not as good as a deep nasal swab. This study suggests that doctors are right — saliva is only 90% as effective:
“We have previously demonstrated that saliva has a high concordance rate of greater than 90% with nasopharyngeal specimens in the detection of respiratory viruses, including coronaviruses. In some patients, coronavirus was detected only in saliva but not in nasopharyngeal aspirate.”
When this February 12 report was shared with doctors in early March, they noted that a saliva sample would degrade. When asked if saliva could be stabilized using a liquid added to the sample, doctors said that might work — but it would still be hard to overcome the protocol to use nasal swabs because the results are better (even if they are only slightly better).
The FDA has agreed that saliva can be used and recently approved a saliva test developed at Rutgers that uses a liquid to stabilize the saliva. For frequent population-scale testing, saliva samples are easier to collect, not painful, do not expose health care workers during collection, and do not rely on swabs that are in short supply.
Pooled testing.
Pooling is just like it sounds. Multiple saliva samples are placed in the same test container. If one or more people in the group have the virus, it will show up in the group test. If the pooled test is negative, the whole group is negative — which will usually be the result when the infection rate in the population is low. If the group test is positive for the virus, a second round of individual tests would be performed.
Pooled testing, combined with a switch to saliva instead of nasal swabs, could massively increase testing capacity without waiting for a new technological breakthrough. When doctors were asked about pooling samples in March, they said that it cannot be done. When asked why, they said it just isn’t done that way — protocol again.
This group in Israel proved that pooled testing worked with up to 64 blood samples in a single PCR test:
And a team at Stanford showed pooled testing worked with nasal swabs:
It is not surprising that pooled testing works. PCR tests multiply the target virus and make billions of copies. If enough of the virus is present in the sample, it’s going to show up in the results at the end of the PCR test — and the virus is present in saliva.
To make collection relatively clean, we could use small pieces of PVA sponge (commonly used in medical procedures) which could be treated with a liquid that stabilizes saliva. These could be individually wrapped — like a Lifesaver, but with a tiny sterile sponge inside:
The subject could be asked to put the sponge in their mouth, clear their throat with their mouth closed, chew on the sponge, then spit the sponge into a container. We could create a sophisticated system using QR codes and an app, but if we assume an extremely low infection rate in the population returning to work after isolation, the system could be simple:
- samples from 20 to 50 people go into the same container — based on proximity to each other in the building. In an office tower, perhaps the building is divided into floors and then subdivided if needed
- a unique number/code on each pooled container
In the rare cases where a pooled sample tests positive, we immediately inform the organization that submitted the pooled test and ask them to send everyone in that pool home. Everyone in the positive test pool would be directed to visit a list of facilities where they can be tested for free and quickly (this could be paid for by their employer or a fund we set up — but it should be free and easy to do). Those with negative individual test results could return to work and those with positive results would be quarantined at home.
This simple/shared testing approach has an added benefit — privacy. No individual samples at the workplace or school means no one has to worry that their employer or government might test them for something other than this virus. It would be impossible to do so.
Most companies will be willing and able to pay to participate in this system. If the cost per person is low (like $2 per day), it will be an easy decision. For offices with multiple tenants, the cost could be included in their CAM charges (common area maintenance) for the building — just like cleaning services and security.
Austin has approximately:
- 778 large offices (over 20,000 square feet)
- 527 restaurants and 462 bars
- 109 pharmacies and 73 supermarkets
- 129 schools (AISD)
This list does not include retail, industrial, government, hotels, etc — but even with those added, the number of collection locations appears to be in the thousands. This will not be easy, but these seem like manageable numbers. We would just be testing workers at these locations, not customers.
These tests could be run daily at first as we return to work and school. As the infection rate in the population declines, the frequency could be reduced to every other day, then once a week — or even random. For some groups like health care workers and those preparing food, it might make sense to permanently make daily testing the standard.
Contact tracing
Testing must be combined with contact tracing to fill in the gaps. Contact tracing means finding each sick person and then figuring out who they recently interacted with and testing those people. Experts agree that contact tracing alone won’t stop the spread:
With approximately 44% of transmission occurring prior to the onset of symptoms, we need both population-scale testing and the new automated contact tracing system from Apple and Google:
The biggest limitation of Apple and Google’s new contact tracing system is not technical. It is likely that any contact tracing system in the US will be voluntary — and some people will not sign up.
The new goal — get R0 under 1 without quarantining most of the population.
After 9/11, what if TSA had focused on increasing security measures after people boarded planes instead of testing everyone before they boarded planes? What if our response after 9/11 was focused on catching people after they board a plane with a knife, gun, or bomb? With this virus, we test people after they are sick, and after they have already infected others. It is not surprising people are scared and that only 20% of the population is ready to go back after restrictions are lifted.
If we want to “unscare” people we need to start testing infected people before they infect other people.
- Fever screening at work, school, and public venues
- Saliva samples at work and school combined with pooled testing
- Contact tracing using Apple and Google’s new system
We have tools that did not exist during the 1918–19 Spanish Flu pandemic — non-contact thermometers and thermal imaging cameras for fever detection, PCR molecular testing, the ability to map and edit genomes, and mobile computers in our pockets that can automate contact tracing. There are many reasons to believe that we can do better than we did 100 years ago during the Spanish flu. If we use these tools, make visible changes, and can prove the risk from the virus is lower than driving a car to work, we will recover from this sooner than currently expected.
UPDATE:
Yale School of Medicine study shows saliva may be better than nasal swabs:
