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New Online Calculator Estimates COVID-19 Mortality Risk

Analysis  |  By Christopher Cheney  
   December 18, 2020

Individuals can use the online calculator to estimate their risk of dying from COVID-19 if they become infected with the coronavirus.

Researchers at Johns Hopkins Bloomberg School of Public Health have developed online tools for estimating individual and community-level risk for COVID-19 mortality.

COVID-19 has become a leading cause of death in the United States. As of Dec. 18, more than 17,600,000 Americans had become infected with the coronavirus and more than 317,000 had died, according to worldometer.

The new online tools feature an online calculator that individuals can use to estimate their risk of dying from COVID-19 as well as interactive maps for viewing numbers and proportions of individuals at various levels of mortality risk across U.S. cities, counties, and states. The online tools are based on information drawn from several U.S. databases and the United Kingdom-based OpenSAFELY study.

The online risk calculator combines individual risk factors such as age, weight, and pre-existing medical conditions with community-level pandemic dynamics. As a result, if infections spike in a community, the mortality risk estimates for individuals will increase in that community. The data underlying the online tools is updated weekly.

A detailed description of how the online tools work was published recently in a Nature Medicine article.

"We developed a COVID-19 mortality risk model for the general U.S. population by combining information across multiple data sources. We believe that the model is unique in that it can be used to project absolute rate of mortality for individuals with different risk profiles by combining information on individual-level risk factors, as well as on changing dynamics in the epidemic at the community-level captured through available forecasting models. We applied the model to data available from U.S. national databases to identify high-risk cities and counties and estimate the size of populations at risk within these communities," the journal article's co-authors wrote.

High-risk cities include Baltimore City, Detroit, Miami, New Orleans, and Philadelphia, according to the journal article.

Applying the online tools

The senior author of the article told HealthLeaders that the online risk calculator is a powerful tool to assess COVID-19 mortality risk and help determine who should be prioritized for vaccination.

"The current guidance provided by the Centers for Disease Control and Prevention is to vaccinate healthcare workers and older individuals living in congregated conditions using the initial supplies of vaccine doses by the end of this year. After that, one of the major questions would be how individuals in the general population would be prioritized based on age and pre-existing conditions to receive vaccines. It is also known that individuals from certain minority populations as well as neighborhoods with high social deprivation have high risk. Further, the risk can widely vary for individuals based on the intensity of the pandemic in their communities at a given time," said Nilanjan Chatterjee, PhD, a professor of biostatistics and epidemiology at the Johns Hopkins Bloomberg School of Public Health.

The online risk calculator is unique and well-suited to prioritizing individuals and communities for vaccination because it generates quantitative information, he said.

"While the CDC and National Academy of Science, Engineering and Medicine have developed broad guidelines regarding how different factors may be prioritized, a risk calculator, such as ours, brings all of these factors together and weights them to define a single score according to their overall contribution to risk of mortality.  Our risk calculator can help to bring in more quantitative risk information into vaccine prioritization than has been considered before."

Quantitative information is crucial in determining vaccination prioritization, Chatterjee said.

"Without quantitative analysis of risk, it is hard to figure out how all of this information should be weighed to come up with an optimal vaccine distribution strategy that will save the most lives. In our analysis, we were able to show if vaccination is performed based on underlying risk information, large proportions of deaths—about 50%—in the population could be quickly averted by vaccinating relatively small proportions of the population—less than 5%."

High-risk cities share a combination of risk factors, he said. "Many high-risk cities have a high proportion of African Americans, who are known to be at increased risk of COVID-19 infection and mortality. Further, these cities also rank high in social deprivation due to various socioeconomic conditions, which, independent of ethnicity, can contribute to risk of infection as well as complications after infection."

Related: Researchers Detail Challenges of Determining Coronavirus Mortality

Christopher Cheney is the senior clinical care​ editor at HealthLeaders.


KEY TAKEAWAYS

The online COVID-19 mortality risk calculator combines individual risk factors such as age, weight, and pre-existing medical conditions with community-level pandemic dynamics.

In addition to the online risk calculator, researchers at Johns Hopkins Bloomberg School of Public Health have developed interactive maps for viewing numbers and proportions of individuals at various levels of mortality risk across U.S. cities, counties, and states.

High-risk cities share a combination of risk factors such as a relatively high proportion of African Americans, who are known to be at increased risk of COVID-19 infection and mortality.


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