Staff photo by C.B. Schmelter / A worker takes a sample at the Alstom COVID-19 testing site on Tuesday, Sept. 22, 2020 in Chattanooga, Tenn.

While Hamilton County continues to report its lowest COVID-19 new case totals and hospitalizations in months, fewer people are being tested for the virus, which could hinder local understanding of the pandemic, especially as the spread of coronavirus variants appears almost certain.

As of Friday, the county was running a seven-day average of about 700 new COVID-19 tests a day. This is down from around 1,900 new tests a day in December and 1,400 new tests a day at the beginning of January. The current level of daily testing is the lowest it has been since the county began reporting daily testing numbers in July.

Aditya Khanna, assistant professor of behavioral and social sciences at Brown University, said decreasing levels of testing should be concerning given the threat of coronavirus variants, which appear to be more transmissible than the current version in the United States. On Thursday, Hamilton County Mayor Jim Coppinger confirmed a variant of SARS-CoV-2 was circulating in the county.

The presence of variants, which may cause some mild reinfections for people who have already gotten sick, means people are potentially still at risk for the virus even when case counts appear to be dropping. Scientists are still studying the effects of the variants, but existing vaccines appear to stop the most serious cases of infection from the new variants.

There is a kind of cyclical relationship between testing and case counts, Khanna said. When case counts are high and there is attention to the spread of the virus, people may be more likely to think they could get infected or think their symptoms could be COVID-19.

"If people are testing a lot and they notice that the situation is getting worse, then it provides motivation for people to keep their guard up and be very careful about social distancing and other things," he said. "If the testing starts dropping, people don't know as much about whether or not they're positive, then there are chances that people can get less particular about continuing to be careful."

Case counts and hospitalizations have fallen in Hamilton County in the past six weeks, reaching some of their lowest points since October. There was also incentive for people to be tested ahead of the winter holidays if they were traveling to see family or loved ones, which could have increased testing numbers at the time.

Khanna said lower levels of testing also mean the public is getting a less detailed understanding of the virus in the community. COVID-19 testing is not a representative sample of the population since it favors people who have access to testing and take time off work or other things to get tested. It also favors those who have symptoms or are more in tune with their bodies. Because asymptomatic people with COVID-19 are less likely to be tested, a definitive rate for asymptomatic cases is unknown, but some researchers have estimated it could be between 1 in 6 and 1 in 3 cases.

Despite the falling case counts, Hamilton County is still experiencing a high positivity rate for the tests it does conduct. As of Friday, the county averaged a positivity rate of around 11% on new tests in the past week. Health experts have said a positivity rate below 5% on new tests is a sign the virus is contained in a given community.

Continued COVID-19 testing will play an important role in understanding and controlling the spread of the virus while millions of Americans do not have access to the vaccine, Khanna said.

"Vaccines are certainly a very, very positive tool in the tool box to contain the epidemic," he said. "But I would be surprised if vaccines were able to do it all without the behavioral and the nonpharmaceutical interventions, especially when we're in the early stages of the rollout."

Becky Barnes, administrator for the Hamilton County Health Department, said people who are symptomatic or who have had exposure to the virus need to be tested. The county offers free testing for the virus at the former Alstom Plant site on Riverfront Parkway from 10 a.m. to 2:30 p.m. Monday through Saturday. Testing is available by appointment at Clinica Medicos, and Cempa Community Care is offering testing at Alleo Health Monday through Friday from 8 a.m. to 1 p.m.

Health experts have continued advocating for the use of face masks and other mitigation measures, like hand washing, until the levels of vaccinated people increase and scientists have a better understanding of the existing variants. While there are some cases of the variants infecting people who have been vaccinated, the existing vaccines have proven effective against serious cases of COVID-19 resulting in hospitalization or death.

Contact Wyatt Massey at or 423-757-6249. Follow him on Twitter @news4mass.