Staff Photo by Matt Hamilton / CMA Evelyn Wilson, talks people through the self-swabbing routine in the drive thru on Wednesday at 4411 Oakwood Drive.

Health officials are bracing for a potential COVID-19 case surge as a result of Labor Day parties and social gatherings.

Spikes in new coronavirus cases have followed in the weeks after national holidays throughout the pandemic, and Hamilton County as of Thursday had more active cases than it did heading into the Memorial Day weekend or the Fourth of July weekend.

There were 206 active cases in Hamilton County on May 22 and 1,139 active cases on July 3, according to data from the Hamilton County Health Department. As of Thursday, there were 1,701 active COVID-19 cases in Hamilton County.

The case increase that occurred after Independence Day was the largest COVID-19 wave to hit Hamilton County so far, leading to the county's peak hospitalizations in July and deadliest month thus far in August.

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Can Chattanooga expect another COVID-19 surge?

Dr. Mark Anderson, an infectious disease specialist at CHI Memorial Hospital, said during a news conference Thursday that it's not a guarantee the pandemic will worsen as a result of Labor Day, but it's possible.

"We're on the alert for it," he said. "It's something we're all going to be monitoring, the health department is going to be monitoring."

He said that college students who are away at school and returning home to see family could be one group that poses a higher risk of transmitting the virus.

Rae Bond, chair of the local COVID-19 Joint Task Force, said during a news briefing on Tuesday that just because people may be spending time with friends and family, that doesn't mean it's safe to let your guard down.

"As we go into Labor Day, we want to really urge folks to avoid large gatherings, to continue wearing masks and continue practicing social distancing," Bond said. "If you need to have gatherings, make them small, stay at home, mask up and do your social distancing."

On Friday, the health department reported that Hamilton County had only 901 active cases. The large drop from Thursday came as the state announced a new way of calculating active cases, based on an assumption that the virus remains active for 14 days, rather than 21. It's unclear how many cases Hamilton County would have had going into the Memorial Day or Fourth of July weekends using the new methodology.

(READ MORE: Labor Day weekend travel driven by road trips as people stay closer to home while COVID-19 pandemic persists)

Contact Elizabeth Fite at or follow her on Twitter @ecfite.