As countries across the globe shift focus on Covid-19 vaccination exercise, researchers at Johns Hopkins Bloomberg School of Public Health have developed a new online “Covid-19 mortality risk” calculator to help health authorities prioritise certain groups for vaccination.
“Our calculator represents a more quantitative approach and should complement other proposed qualitative guidelines, such as those by the National Academy of Sciences and Medicine, for determining individual and community risks and allocating vaccines,” said study lead author Nilanjan Chatterjee, Bloomberg Distinguished Professor in the departments of Biostatistics and Epidemiology at the Bloomberg School.
The new risk calculator is presented in a paper published in the journal Nature Medicine.
The researchers also collaborated with PolicyMap, Inc. to develop interactive maps for viewing numbers and the proportion of individuals at various levels of risks across U.S. cities, counties and states. These maps will allow local policymakers to plan for vaccination, shielding high-risk individuals, and other targeted intervention efforts.
“Although we have long known about factors associated with greater mortality, there has been limited effort to incorporate these factors into prevention strategies and forecasting models,” Chatterjee said.
He and his team developed their risk model using several Covid-19-related datasets, including from a large U.K.-based study and state-level death rates published by the Centers for Disease Control and Prevention, and then validated the model for predicting community-level mortality rates using recent deaths across U.S. cities and counties.
The calculator based on the model is available online for public health officials and interested individuals alike. It enables a user to determine individual risk based on factors such as age, sex, race/ethnicity, and medical history and can be used to define risk for a group, such as for a particular community, corporation, or university, based on the mix of relevant factors that define the group.
The calculator allows users to calculate mortality risk of individuals by combining information on individual-level factors with community-level pandemic dynamics, as available from a large variety of forecasting models. Thus, when a big wave of infections hits a population, the risk estimates for individuals will rise in that community. Currently, the tool is updated on a weekly basis to incorporate information on state-level pandemic dynamics.
“People may understand broadly that with a preexisting condition such as obesity or diabetes, for example, they are at higher risk, but with our calculator they should be able to understand their risk in a way that takes multiple factors into account,” Chatterjee said.