New data and models offer additional insights into how COVID-19 will affect North Carolina in the coming months. The work includes an interactive platform that offers statewide or county-level projections of how changes in risk reduction efforts – such as mask use – and the increase in more infectious variants of COVID-19 could affect the spread of COVID in North Carolina.
While the platform looks at metrics such as infections, hospitalizations and deaths at the state level, the county-level models focus solely on infections.
The work stems from a complex model developed by researchers at North Carolina State University, the University of North Carolina at Chapel Hill, Georgia Tech and East Carolina University. The model can help us understand the spread of COVID-19 and the factors, such as non-pharmaceutical interventions (NPIs), that influence it. An earlier version of the model, which used data from Georgia to look at the impact of quarantining, was published in BMC Public Health.
“As confident as we are in our findings, we would normally wait until they have passed peer review before making them public,” says Julie Swann, who played a lead role in the modeling work. “However, we are seeing a lot of discussion, in headlines and elsewhere, that suggests the pandemic has run its course in the United States. We think that may be misleading, and feel that sharing these findings now could help reduce the number of people affected by COVID-19 over the next seven months in North Carolina, and in states with similar vaccination rates.” Swann is the department head and A. Doug Allison Distinguished Professor of the Fitts Department of Industrial and Systems Engineering at NC State. Swann also leads a team selected by the CDC and the Council of State and Territorial Epidemiologists (CSTE) to support forecasting, modeling of interventions, and communication of results related to the COVID-19 pandemic.
The model shows that even after 40% of the population has been vaccinated, continued use of masks could prevent hundreds of thousands of additional cases and thousands of deaths in North Carolina by the end of 2021.
“Our model includes recent vaccination data and up-to-date information on the spread of more contagious variants of COVID-19 in the U.S.,” Swann says. “Those contagious variants are now estimated to make up more than 60% of the cases in the U.S.
“Our key findings are that continued use of masks and other NPIs would save lives while providing more time to continue vaccinating,” Swann says. “It is also concerning that we see continued or increased inequities in disease burden under the more infectious variants. In other words, our models suggest that – if we move forward with efforts to scale back risk reduction efforts – there will continue to be a disproportionate number of cases, hospitalizations and deaths in historically marginalized populations.”
“A critical variable affecting cases, hospitalizations and deaths is how infectious the variant of COVID-19 is,” says Erik Rosenstrom, a Ph.D. student at NC State who is involved in the modeling work. “The more infectious the variant, the worse off we are. The variant B.1.1.7 that is now dominant in the U.S. is thought to be 30-50% more infectious than earlier strains.
“Infectivity is something we don’t have control over. But two other important variables are within our control: vaccination and mask use. Getting vaccinated and wearing a mask – particularly for people who aren’t vaccinated – make a big difference. Having only unvaccinated people wear masks is better than masks off, but it is really difficult to enforce.”
“It’s important to note that the vaccines in use in the U.S. are still fairly effective against most of the new variants we’re seeing,” Swann says. “And the vaccines are exceptionally effective at preventing severe illness in those vaccinated people who do become infected. Concerns about new variants make it more important to get vaccinated, not less. While the pace of vaccinations has slowed, we know that continued efforts to reduce barriers to access can help people choose to be vaccinated. Continued efforts can also help raise the vaccination rate in populations where it remains lower, including rural areas, in areas of lower income, and among younger adults.”
The researchers have also developed a platform that allows users to look at the impact of various risk-reduction scenarios they have studied on a statewide or county-by-county basis. Users can access that platform at http://go.ncsu.edu/covsim.
“The tableau dashboard is set up so that you can view county-level model results under specific scenarios,” says Jessica Mele, a Ph.D. student at NC State who is involved with the work. “Currently, you can compare estimates for daily and cumulative infections depending on various combinations of vaccine rollout speed, coverage, efficacy, and whether or not NPIs remain in place. We are estimating true infections, which is often a much bigger number than the lab-confirmed positive cases.”
The work is part of a broad, interinstitutional effort that includes Julie Ivy and Maria Mayorga, who are professors of industrial and systems engineering at NC State; NC State undergraduate Nicole Colberg; Mehul Patel, a research assistant professor of emergency medicine at UNC; Kristen Hassmiller Lich, an associate professor of health policy and management at UNC; Paul Delamater, an assistant professor of geography at UNC; Ross Boyce, an assistant professor of medicine at UNC; Karl Johnson, a Ph.D. student at UNC; Pinar Keskinocak, the William W. George Chair and Professor in Georgia Tech’s H. Milton Stewart School of Industrial and Systems Engineering; and Raymond Smith, an assistant professor of engineering at East Carolina University.
The work was supported by a grant from the CDC and CSTE; and by the National Center for Advancing Translational Sciences, under grant UL1TR002489.