Jumping into Pool Testing---One Solution

Right now, in the United States and elsewhere in the world, there is a significant shortage of COVID-19 PCR (Polymerase Chain Reaction) tests for the presence of the infection. The concept of "Pool Testing" can conceivably allow us to test more people using much less of the reagent, one of the key materials required that happens to be in short supply. Pool testing conserves those scarce commodities by using a fraction of the chemicals than it would have taken to test those numbers of people the conventional way.

How Pool Testing Works

Pool Testing combines samples from multiple people, then uses only one test on the whole group. If the combined sample is negative, the authorities can rule out the presence of infection in that entire group. However, if the result is positive, the pool is divided into smaller samples to identify the infected person or people.

The Advantages of Pooling

Since testing materials are in short supply, pool testing can be more cost-effective, and it can reduce the processing burden on laboratories. Moreover, it can eliminate large numbers of people who are not infected, and who would otherwise have taken an individual test. For large groups, like students or employees, it can act as a surveillance system for asymptomatic people. Finally, pool testing can also speed up the testing process because it requires significantly less processing time than would have been required for all of the individual tests together.

Tremendous Testing Capacity Immediately

According to Dr. Deborah Birx, coordinator of the White House Coronavirus Task Force, "Pooling would give us the capacity to go from a half a million tests a day to potentially five million individuals tested per day." By widely implementing pooling, the US could scale up its testing capacity very quickly. But this method is not without its challenges.

Not Suggested for Everywhere

If states have high rates of positive infections, like over 15 or 20 percent, as we have in states like Texas or Arizona, pool testing will probably not be useful; all of the batches will be positive. Additionally, if the pool is too large, sometimes positive cases will show up as negative. However, in states like New Jersey or New Hampshire, pooling makes a lot of sense.

Number of People in the Pool will Vary

Depending on which machine is used for the test, and who the researchers are, the number of people's samples grouped together will vary. Some scientists believe that up to 10 samples could be pooled, while others recommend single digits up to 50, One study from Israel (not yet peer-reviewed) found that the virus was detectable in a pool as large as 64. Most researchers believe pool testing is the right approach in locations with low rates of COVID-19, where the large majority of tests will be negative; in states with a high prevalence of cases, too many of the pools will come back positive for this method to make sense.

Testing is Just One Element

Without knowing who is infected through widespread testing, it will be impossible to contain the disease. Researchers agree that containment is our best defense in controlling the spread of COVID-19. And we need to be testing everyone, including those without any symptoms. Furthermore, containing the spread of the virus requires not only testing for infection, but also contact tracing for those likely to have been exposed, and of course, isolation for everyone who is infected. 

The Future of Testing

Testing is a major element in controlling the disease, perhaps the most important. I see the future as a combination of the paper testing covered in the previous Herman Trend Alert and in states where it makes sense, pool testing. Once we have contained the virus, we can move to a regimen of pool testing for everyone, until we have a vaccine.

Next Week: COVID-19 Vaccine Update

Besides the vaccines moving into Phase III trials, there is a revolutionary vaccine that has the potential for being thousands of times more effective with fewer side effects. Tune in next week, when I will tell you all about it.

Special thanks to Health.com and MSNBC for their coverage of this valuable tool in our battle against COVID-19.

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Read this Herman Trend Alert on the web: http://www.hermangroup.com/alert/archive 8-19-2020.html