In April, the White House Coronavirus Task Force made headlines by suggesting that the United States should be conducting millions of COVID-19 tests per day. Now, colleges and universities and major employers are looking at ways to ensure the safe return of students and workers. In a switch from the early days of the pandemic in the U.S., many states and communities are encouraging residents to get tested—and retested.

Meeting the high and growing demand for testing has necessitated a movement away from reliance on quantitative polymerase chain reaction tests that can detect tiny bits of genetic material from the SARS-CoV-2 virus. Those tests, while highly accurate, can take days to provide results to patients and require equipment and materials that remain in short supply. 

Quick tests, which typically produce results in minutes and are used by many pharmacies, have lower accuracy but have enabled massive upscaling of testing capability across the country. Is that a good trade off?

According to a preprint study posted to medRxiv on June 27 by researchers at the University of Colorado Boulder and the Harvard T.H. Chan School of Public Health, “effective surveillance, including time to first detection and outbreak control, depends largely on frequency of testing and the speed of reporting, and is only marginally improved by high test sensitivity.” 

The authors found that the viral load trajectory of the coronavirus and disease infectiousness when patients are asymptomatic, presymptomatic, and symptomatic made weekly testing with rapid results the best option for outbreak control. Testing even alternate weeks would be little better than not testing at all in terms of monitoring disease spread on a community level, they determined.

Frequent testing has benefits on the personal level for individuals who have continued working or have returned to work. “If you are daily in contact with people who are need to be tested daily,” said University of California-San Francisco emergency room physician Jeanne Noble in an interview with an ABC television station in California. This group would include healthcare personnel, essential workers such as grocery store clerks, teachers, and others with a high degree of public contact. 

The CDC already recommends weekly testing for all healthcare workers at long-term care facilities. Both healthcare personnel and residents should be tested every 3 to 7 days after initial testing in the event that any resident or healthcare worker tests positive until testing finds no new cases for at least 14 days.

Outside of the healthcare setting, testing remains important. “If you’re in contact with people who are not sick...then something like weekly testing is probably fine,” Dr. Noble said. People in offices who work with a minimal number of people or can maintain their distance from colleagues and customers fall into this category.

Regions of the country experiencing a surge in cases should encourage more frequent testing to better understand outbreaks and limit transmission. "If we truly surge, then weekly testing would no longer be adequate," Dr. Noble said. "We have to keep doing this and redefining testing needs until we have a vaccine."

With two-thirds of states now reporting an increase of cases, pharmacists should be prepared for increased demand for testing and retesting.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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