Widespread testing and contact tracing may be the best way to contain COVID-19 and keep it from a resurgence as jurisdictions look to loosen physical distancing, modelers told a Maryland legislative work group Wednesday.
Because the coronavirus can spread before people with the disease it causes show symptoms, significant testing is key to containing its spread, modelers said.
“Proactive testing in the community — the availability of tests for people to go up and actually get tested and find out how they are, what their infection status is — and contact tracing that can then use that information to go out there and really throttle this disease is vital,” said Jeffrey Shaman, a professor at Columbia University’s Mailman School of Public Health.
He suggested that in places like Georgia that have begun to reopen their states, the true effects may not become known for at least two weeks due to current levels of testing in the country.
Shaman and Justin Lessler, a professor at the Johns Hopkins University’s Bloomberg School of Public Health, separately presented Wednesday their work to the General Assembly’s Joint Covid-19 Response Legislative Work Group.
Shaman and Lessler presented just some of the thousands of possible outcomes that their work has modeled.
Models, they warned, are not forecasts and do not predict the future. They show what could happen under different scenarios to aid in the planning process. The differences in those scenarios can be more important than the specific numbers different models produce, Lessler said.
“We’re really focused on planning scenarios, not forecasts,” he said. “Our goal is to use rough approximations based on our best knowledge and the current situation and severity to project often a lot further into the future than you can really make reliable forecasts.”
Different scenarios for the next few months demonstrate that testing will be critical to reducing the disease’s effects by helping track down people and isolate those who may have COVID-19 before they show symptoms.
That means having enough testing capacity to test both people with symptoms and people whose doctors have not recommended they get tested.
Maryland has begun to increase its testing efforts, including a high of 8,311 test results reported Monday. But various factors, including other supplies and the weather conditions, can vary how much testing is actually done.
The state has averaged 4,914 test results a day over the last week and hopes to test up to 20,000 people a day.
The state has also just begun to increase its contact tracing abilities. Gov. Larry Hogan announced last week a contract with the National Opinion Research Center that could allow the state to contact up to 1,000 new cases a day. That capacity would join the state’s existing workforce of about 250 tracers.
Some resurgence of the disease in the form of a second wave is expected in late summer or early fall, Anthony Fauci, the nation’s top infectious disease expert, said in an interview with the Economic Club of Washington, D.C.
“I’m almost certain it will come back because the virus is so transmissible and it’s globally spread,” Fauci said. “It’s not going to disappear from the planet, which means as we get into next season, in my mind, it’s inevitable that we will have a return of the virus, or maybe even that it never went away.”
Putting the expanded testing and tracing efforts into place would help to contain that spread. Other factors, like new treatment therapies, could also limit the disease’s harm this fall.
Without those countermeasures, the country could be in for a “long” fall and winter, Fauci said.
The most effective method to slow the disease’s spread has been physical distancing and isolation.
But that method’s effectiveness may have begun to wane as people grow restless at home. Some states have begun to relax their physical distancing orders, opening up some businesses like restaurants. But even in areas that have not loosened those rules, people have begun to spend less time at home, according to data from Lei Zhang, a professor in the University of Maryland’s A. James Clark School of Engineering.
His data tracks how much people have been traveling during social isolation, including trips across state lines, trips to the grocery store and trips to work.
While social isolation saw a peak in early April, people have begun to move a little more frequently since Easter as “quarantine fatigue” sets in, Zhang said.
“Maryland is actually doing really well in terms of social distancing,” he said. “But unfortunately starting on the Tuesday after Easter, April 14, we started observing nationwide a reduction in social distancing and mobility behavior. …Maryland also has this issue. We are seeing a slight drop in social distancing behavior, but this issue is much worse elsewhere in the country.”