While the progress toward widespread COVID-19 vaccination is encouraging, testing, masking, social distancing, contact tracing and isolation will continue to play a key role in limiting outbreaks and keeping schools and businesses open.

But how can the leaders of these organizations determine what test to use, how often to test, and what the costs and potential savings could be?

A team from Massachusetts General Hospital and the Massachusetts Institute of Technology (MIT) has created an online tool to help organizations calculate the costs and benefits of different COVID-19 testing and mitigation strategies.

The calculator, which is available for free at http://whentotest.org, is a collaboration between the Mass General-based Consortia for Improving Medicine the Innovation and Technology (CIMIT) and the Institute for Data, Systems, and Society (IDSS) at MIT.

It was developed as part of the National Institutes of Health’s Rapid Acceleration of Diagnostics (RADx) Tech program, which was established by the federal government to speed the development and implementation of new tests for SARS-CoV-2 infection.

A Multifunctional Modeling Tool

The calculator enables users to model different testing strategies based on the number of people typically onsite in their organization, rates of mask usage and the number of unmasked group activities—such as dining—that typically take place.

Users can also look at the impact of different testing strategies and what to expect in terms of how many people should be tested each day and testing cost per week.

Business owners can weigh the cost of testing (materials and individuals to conduct tests) against the potential loss of revenue due to an onsite outbreak.

After building out a model of their current situation, users can then see how different testing and prevention strategies could help.

The goal is to make it easier to navigate the overwhelming amount of testing information out there and to reduce risks in schools, businesses and other organizations where individuals are gathering on-site, explains CIMIT’s Paul Tessier. Tessier co-founded When to Test along with Anette “Peko” Hosoi, PhD, the associate dean of engineering at MIT and an affiliate of IDDS.

“One of the reasons the website is effective is that we don’t dictate what to do,” says Peko. “Instead we give you a tool you can use to balance different mitigation strategies against whatever constraints you have in your organization.”

From Spreadsheet to Website

The calculator began as a spreadsheet created by Tessier in the spring of 2020, after he began ramping up the development of diagnostic tests as the operations lead for RADx Tech at CIMIT.

“It quickly became obvious to me that it’s one thing to develop tests, it’s a whole other thing to help people understand what it means to implement these tests,” he explains.

In the summer of 2020, Nancy Gagliano, MD, MBA, the implementation lead for RADx Tech, connected Tessier to Hosoi, who had been exploring COVID-19 mitigation strategies from a systems control perspective.

“Imagine you have a set of levers you can pull to control the spread of the virus, such as masking, testing, contact tracing and isolation,” Hosoi explains. “We wanted to quantify the impact of pulling each of those levers.”

“What we lacked was the information about the types of tests available, their sensitivity, their costs—all the things that Paul had put together,” she says.

“But we did have a calculation that filled the hole in Paul’s spreadsheet, namely how to integrate all of the different mitigation strategies to limit the risk of an outbreak in your organization.”

Looking Toward the Future

As vaccination rates increase, there will still be a need for other mitigation strategies, Hosoi says. Vaccines are currently not available for children and there is still a significant number of individuals who don’t feel comfortable receiving them.

“I think if we shift our attention entirely away from testing in favor of the vaccine, we will regret that a few months down the road,” she says.

Gagliano says the team has a number of significant enhancements planned in the near future. The next release will provide access to purchase tests, services, and PPE to support the implementation of a testing program. Additionally, pooling, confirmatory testing, and the impact of vaccination will be added to the calculator.

They are also working to make the website and calculator more user-friendly, including providing more decision support, while still preserving its ability to model many different variables and highlight useful resources. “I think we still have a way to go,” Tessier says. “It’s a complex problem, but we’re on the right track.”

“One of the heartwarming things is the number of people who have used the site and told us it’s exactly what they’ve been waiting for,” he adds. “They’ve seen so much information out there, but no one has pulled it together for them in a way they can understand and use.”

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Research at Massachusetts General Hospital is interwoven through more than 30 different departments, centers and institutes. Our research includes fundamental, lab-based science; clinical trials to test new drugs, devices and diagnostic tools; and community and population-based research to improve health outcomes across populations and eliminate disparities in care.
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