Modelling masters

A Memorial research team has developed mathematical models to inspire future public health responses to infectious diseases.

Dr. Amy Hurford, an expert in infectious disease modelling in the Department of Biology, Faculty of Science, is working in partnership with Julien Arino and post-doctoral fellow in the Department of Mathematics, Dr. Maria Martignoni. 

It has been over four years since the onset of the COVID-19 pandemic, and public health responses and policies continue to vary worldwide.

The effects of these policies are far-reaching and are still felt in every corner of the province, country and world.

These policies can be boiled down to two unique strategies: infection elimination or mitigation. 

Led by Dr. Martignoni, the research team identified the need for guidelines that evaluate the appropriateness of an elimination or mitigation strategy early in the pandemic and have been aiding government officials and working groups in Canada to navigate the implementation of policies since 2020.

Their research has now culminated in a quantitative analysis and modelling that will change how future public health policies are implemented.

Mathematical modelling

Elimination strategies, which aim for zero community transmission, have been successful in regions with low travel volumes and strict border control measures, they say.

On the other hand, mitigation strategies, which focus on reducing transmission to manageable levels, are more suited to well-connected and densely populated areas.

“Different public health responses are appropriate for different local contexts.” — Dr. Amy Hurford

Recognizing the importance of building connections between the two modelling frameworks of disease mitigation or elimination, Drs. Hurford and Martignoni developed a theoretical framework based on research conducted throughout the COVID-19 pandemic relating to implemented health policies around the world. 

Their manuscript published June 19  in the prestigious journal Royal Society Open Science details the modelling, including common errors and misconceptions that bias against recommending one strategy over another. 

The study, Is SARS-CoV-2 Elimination or Mitigation Best? Regional and Disease Characteristics Determine the Recommended Strategy, offers a detailed analysis of elimination versus mitigation approaches, tailored to regional characteristics and specifics of the SARS-CoV-2 virus and variants.

The publication in Royal Society Open Science not only highlights the innovative work being done at Memorial University, but also reinforces the critical role of evidence-based quantitative research in guiding public health policy, the researchers say. 

Key findings

The findings emphasize that the effectiveness of COVID-19 strategies depends heavily on local factors.

Infection severity, health care capacity, the efficiency of case detection, the vaccination status of a population and the economic and societal costs of public health measures all have a fundamental role in determining which strategy should be implemented, and when. 

The paper provides a comprehensive framework to guide policy-makers in deciding between elimination and mitigation, taking into account the economic and social costs associated with each approach. 

“Elimination can be a valid public health strategy in some regions, and mitigation equally valid in others. Our work supports all regions by highlighting that different public health responses are appropriate for different local contexts,” explained Dr. Hurford.

Local application

For Drs. Hurford and Dr. Martignoni, Canada provided the perfect field of study for their research.

“In Canada, many public health decisions were made at the provincial level,” said Dr. Martignoni. “The COVID-19 pandemic in Canada was fairly unique in that there was a need for a modelling that could support both elimination and mitigation approaches.”

The researchers applied their framework to Canadian provinces and territories, highlighting the diverse responses across the country.

For instance, the Atlantic provinces and northern Canada successfully implemented elimination strategies early in the pandemic, benefiting from their geographical isolation and lower population density.

In contrast, provinces like Ontario and Quebec adopted mitigation strategies due to their large urban centers and high connectivity, making elimination impractical.

The study underscores the importance of flexible and adaptive public health policies that consider regional characteristics.

The authors also stress the need for ongoing reassessment of strategies as the virus evolves and new variants emerge.

Inspiration for future policy

This publication marks a significant contribution to the field of public health, providing valuable insights that can help shape future responses to pandemics or infectious diseases in general.

The framework developed by Drs. Martignoni and Hurford offers a valuable tool for policy-makers worldwide, enabling them to make informed decisions that balance public health needs with economic and social considerations.

“This work has inspired future modelling,” said Dr. Hurford. “It helped lead to the formation of a new working group and has inspired applications to other diseases and in other settings.”

Dr. Martignoni agrees.“We want other people to read our work and think: ‘That’s something I want to contribute to!’ We want them to get inspired, such that we can join forces to produce a body of work that will help us better determine the circumstances under which disease elimination or mitigation is best, to optimize future pandemic responses.”