Managing fluctuating COVID-19 testing demand

Aug. 25, 2021

As the SARS-CoV-2 Delta variant surges throughout the United States, so has the number of cases and, therefore, the demand for SARS-CoV-2 testing. According to data from the Coronavirus Resource Center at Johns Hopkins University, testing volume was 1,375,959, or 419 per 100,000, with a positivity rate of 11.5% on August 13, 2021. The situation was quite different on June 10, 2021, when the United States conducted 487,395 tests, or 149 per 100,000, with a positivity rate of 4.0%.

Even so, testing volumes are not close to what they were earlier in the pandemic, such as during the 2020 holiday season. For example, the United States conducted 2,031,894 tests on December 24, 2020, according to The COVID Tracking Project, which no longer collects and reports daily data.

Current testing volumes are fueled by both vaccinated and unvaccinated people. The Centers for Disease Control and Prevention (CDC) recommends testing asymptomatic vaccinated people who come in contact with a person with COVID-19.

A recent study published in the CDC’s Morbidity and Mortality Weekly Report (MMWR) found that cycle threshold values, which indicate viral load, were similar among specimens from patients who were fully vaccinated and those who were not. The study was based on 469 cases of COVID-19 among Massachusetts residents who had traveled to a town in Barnstable County, MA, where several large public events were held in July. A total of 346 (74%) of those infections occurred in fully vaccinated people.

CDC officials said the results of the study influenced their decision to recommend that fully vaccinated people wear masks indoors in geographic locations with high transmission rates for SARS-CoV-2.

With a rapidly changing situation, labs now are in the position of managing fluctuating demand for SARS-CoV-2 testing, as well as for other infectious diseases, such as flu or respiratory syncytial virus (RSV).

 Since the volume of SARS-CoV-2 testing is down overall, compared to the pandemic’s peak, labs also are evaluating what to do with the extra capacity for molecular testing on analyzers they purchased earlier in the pandemic.

For example, David T. Pride, MD, PhD, Director of the Molecular Microbiology Laboratory and the Associate Director of the Clinical Microbiology Laboratory at UC San Diego Health, writes about his organization’s plan for excess capacity in this issue of Medical Laboratory Observer (MLO). The plan includes expanding the lab’s menu to include tests that were sent out to reference labs in the past, such as in sexual health, and preparing for the upcoming respiratory disease season.

I suspect that many of you are implementing similar plans. The editors at MLO would love to hear about them, so please reach out.

I welcome your comments, questions, and opinions. Please send them to me at [email protected].