Why Testing Improvements Are So Critical
It’s time to talk about testing again. Everyone thinks we are doing it badly and we are. Until we do better we are not going to be close to back to normal.
We need tests for three different purposes:
- Confirming people are sick
- Testing where the outbreak goes
- Using tests to allow entry into buildings, schools, and activities
Tests to confirm people with symptoms are sick need to be quick turnaround time. We’re currently not doing that. The only way there is to reduce cases and infection levels. The last three months have made it impossible.
The PCR tests should be able to keep up with demand if we lower demand and if we specialize on using them for sick people. Accuracy is important, but it’s also time that PCR tests are required to meet a turnaround time standard.
The second use for tests are to test asymptomatic people. These can be run at state labs by health agencies and should be available everywhere. The primary purpose for these tests should be to see where the virus is spreading so we can catch invisible cases and isolate.
These tests need to be accurate but not as accurate as PCR tests. Mostly they need to be cheap and easy and not compete for the same resources — swabs and specialized reagents — as the first type of test.
SalivaDirect is a roughly $5 test. It uses (you guessed it) saliva. And interchangeable reagents. Because these are asymptomatic people, they can be run in pools, another reason they can be done more cheaply.
These tests can add millions to the stockpile of tests we can do each day. Even if they’re not perfect, they will help us fight the virus.
Neither of these tests matter without two other things — isolation capabilities and contact tracing.
Dr. Tom Frieden will be on my podcast on Monday. He has pioneered many of these approaches. One of the key things Tom points to is a place we are falling short and that is looking at some of the most important data. How many positive cases are successfully isolated so they are terminal end-the-line cases?
Across Europe with successful programs, that can be 60% to 70%. In the United States most areas don’t even report that number, but in areas with high case count and limited to no contact tracing, that can be as low as 2% to 5%. We can’t improve until we can track and fix this.
The third type of test is the type of test that we can use to enter buildings, offices, arenas, schools, and universities. These tests ideally are self-administered, can be paper-based (like a pregnancy test), done at home, and are not very expensive.
These home-based and event-based antigen tests are going to be less accurate. They may cost $15 (they must be cheaper to be useful) and are a ways away from being approved in the U.S.
This could work a variety of ways, including: using a smartphone to read the color and also store so you could gain admission places. A reading device at an entrance. A location like a CVS where you can go to get it read and carry the result with a time stamp.
Are we okay with these being less accurate? As @somuchweirdness points out, in some ways it’s the equivalent of using a surgical mask. It may be inferior to using an N95 but better than just having your breath meet the air.
Because they are lower accuracy, if you are setting up admission to a school or an event, it may best be used in combination with other NPIs like a mask. No symptoms rules out 60% of people. If a test were only 60% accurate, that would rule out another 25%. A mask another 10%.
So in combination you could enter an office or a school ruling out a 95% likelihood of being exposed.
We need the cooperation of the FDA to get these tests approved with the appropriate level of sensitivity. That is — don’t expect an entrance test to be as accurate as a hospital test. People frequently ask what they can do to help. This website is one way.
We are still in early innings. Tests are game-changers. Imagine if by January we had an abundance of all three of these types of tests. Plus we’re isolating and tracing. Here’s what would happen:
- School wouldn’t be in question
- We would have no testing backlog
- Anyone could get a test any time
- We could all feel safe going places
- Contact tracing would be easy given the frequency of testing
- Economic activity would increase and we would be reducing the spread and saving lives.
And people in high-risk jobs, nursing homes, and communities on the margins would be much much safer. In combination with vaccines and therapies, mask wearing, and safe habits, you can imagine life returning closer to normal.