Rapid Antigen Tests: A Missed Opportunity

At $5 per test, RATs were a bargain compared to other public health interventions.

In a recent paper, Covid in the Nursing Homes, Alex Tabarrok and I examined the pandemic in great detail, focusing particularly on policies that failed to protect nursing home residents. I would like to briefly review our discussion of COVID testing, and how new evidence in this area is pointing toward Rapid Antigen Testing as a missed opportunity.

We document how, instead of encouraging private test suppliers to enter the market, the Centers for Disease Control and Prevention first botched the creation of their own test, then prohibited private actors from using it, and when, on top of that, the Food and Drug Administration broke long-standing practice and issued an “emergency requirement” that lab-developed tests be pre-approved, the result inevitably was very limited testing. These cascading errors meant that by the time a facility had a positive test, the virus would already have spread throughout the facility, contributing to COVID’s devastation of nursing homes, especially in the early stages of the pandemic.

What did surprise us, as we worked on the paper, was the failure of point-of-care Rapid Antigen Testing to fix this:

“Unfortunately, requirements and point-of-care tests did not turn the tide on testing, even though two-thirds of nursing homes had test capability by the middle of September [2020. ...] It took until late November–December before nursing homes were running a million weekly antigen tests and, even then, they ran more of the slower, more expensive lab tests. Why weren’t the rapid antigen tests used much more frequently?”

I’m still not sure we have an answer to that question, but it increasingly seems like we were right to call this a missed opportunity. Our analysis found testing each resident one additional time each week for a year was associated with 1.54 fewer facility COVID deaths, an 18% reduction. In a paper published yesterday in the New England Journal of Medicine, McGarry, Gandhi, and Barnett look at the same question and find a very similar answer:

“the performance of one additional test per staff member per week was associated with a 30% reduction in resident Covid-19 cases and a 26% reduction in related resident deaths.”

This is a topic I’ll likely return to in more detail, but it seems increasingly clear Rapid Antigen Tests were underutilized. At $5 per test, the authors calculate it would only cost $13,000 to save a nursing home resident’s life, a bargain compared to most other public health interventions.