TORONTO, May 26, 2021 – What level of immunity against COVID-19 do you have after being vaccinated or contracting the virus? 91ŃÇÉ« Professor is receiving a $200,000, one-year grant from the National Research Council of Canada (NRC) to understand the rate of immunity in both of these scenarios.

The is part of the NRC’s designed to bring the best Canadian and international researchers together to fast track research and development aimed at specific COVID-19 gaps and challenges as identified by Canada's health experts.

Heffernan, Inaugural 91ŃÇÉ« Research Chair (Tier II), Multi-Scale Methods for Evidence-based Health Policy in the Faculty of Science, is leading the study with colleagues James Ooi, the NRC’s Pandemic Response Challenge program project lead, and M. Sajjad Ghaemi, NRC research officer, both from the NRC-Fields Collaboration Centre.

“Different vaccines elicit an immune response using different pathways, which affects the level and type of immunity you build,” says Heffernan of the Canadian Centre for Disease Modelling. “With this research, we’re tracking the activation of the immune response that’s been excited by vaccines, looking at the generation of antibodies, as well as memory B cells and T cells. Clinical trials can measure the number of antibodies, but they don’t measure B cells and T cells.”

To do this, the researchers will combine mathematical models of immunity development (mechanistic models) with machine learning algorithms to better understand the outcomes of immunity to the SARS-CoV-2 virus after one- and two-dose regimes of adenovirus (AstraZeneca, Johnson & Johnson), mRNA (Pfizer and Moderna) and protein subunit (Novavax) vaccines. They will model the effectiveness and immunity response to the virus, including pathogen mutations and variants, when vaccines doses are given days or weeks apart or as is the case in Canada currently, four months apart.

The researchers hope the mechanistic models will enrich the dataset upon which the machine learning framework is trained. By combining new datasets that are being released publicly, this approach can potentially advance the accuracy of the machine learning framework. This will allow the researchers to classify outcomes of vaccinations as emerging evidence becomes available.

The idea is to uncover the complex interactions between interferon signalling pathways and the adaptive immune response to SARS-CoV-2 infection and vaccination.

“When you model outcomes in antibodies, it’s important to try to model the development of these memory cells in the background. Antibodies protect you from being infected and if they fail, it’s the memory cells that give you that activate factor that allows you to have a milder infection,” says Heffernan.

One of the goals of this research is to tailor vaccines to people’s body chemistry. “This is well into the future, but the goal eventually is to develop inhouse models for mRNA, adenovirus and protein subunit vaccines that can be used to inform what type of vaccine a person should get depending on the characteristics of their immune system,” says Heffernan.

In the short-term, the researchers hope to predict the outcomes in children of various vaccines even without the results of a clinical trial. Based on the differences in immune response of children versus adults, the idea is to change the machine learning and mechanistic models calibrated for adults so that they fit the characteristics of children.

The modelling can also be expanded in the future to test other types of vaccines for COVID-19, in addition to vaccines for other viruses.

The data will be provided to public health agencies, such as the Public Health Agency of Canada, the National Advisory Committee on Immunization, the Canadian Immunization Research Network, and academic researchers to inform vaccine design and policy, and predict safety and efficacy of different vaccine types.

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91ŃÇɫ is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change and prepare our students for success. 91ŃÇÉ«'s fully bilingual Glendon Campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education. 91ŃÇɫ’s campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future. 

Media Contact:

Sandra McLean, 91ŃÇÉ« Media Relations, 416-272-6317, sandramc@yorku.ca

The post How immune are you after one or two doses of a COVID-19 vaccine? appeared first on News@91ŃÇÉ«.

TORONTO, Feb. 24, 2021 – Shorter, but more frequent lockdowns, could lead to fewer cases of COVID-19 than the current practice of long lockdowns, found 91ŃÇÉ« researchers, whose modelling considers individual decisions around the personal cost of complying to social measures.

The researchers developed a novel model that reacts to realistic social dynamics, such as non-compliance of physical distancing and isolation, or delayed compliance. They found that social fatigue and the cost of isolation, which could include lost wages or a psychological/social cost, can diminish the effectiveness of lockdowns and lead to worse health outcomes. This cost increases with each lockdown. Cases could increase unless shutdowns are optimized.

“Modelling the dynamics of intervention based entirely on disease progression assumes that people will immediately distance or relax at the beginning or end of a lockdown. The reality of how people react is less straight forward,” says lead researcher Assistant Professor of the Faculty of Science’s Department of Mathematics and Statistics and the Canadian Centre for Disease Modeling (CCDM), which is hosted at 91ŃÇÉ«.

“It’s realistic to assume disease dynamics drive people into isolation, but an individual’s personal decision to relax their isolation often takes their cost of staying at home into account, and this is often missing in current disease models.”

While models generally factor in the larger economic influences, they often miss the smaller individual economic choices. The research team, including Faculty of Science Professor and Assistant Professor Jude Kong both of CCDM, used a model with separate dynamics for isolation and relaxation dependent on the progression of COVID-19 and the cost of relaxing measures.

It’s important to consider and include the isolation cost since repeated lockdowns would have diminishing returns as people’s tolerance, and the financial or psychological burdens of staying at home, become too overwhelming. Having shorter bursts provide less time for this cost to grow, say the researchers.

“Using a dynamic response model allows for more realistic policy strategies for disease mitigation and mortality prevention,” says Moyles. “Understanding how people will react to a change in policy regarding lockdowns or bans on social gatherings will inform how and when to enact social measures for maximum effectiveness. This is essential in gauging the impact that COVID-19 and mitigation strategies will have on infections and mortality.”

Improving this aspect of modelling, could ensure policies are put into place at the right time so people will react accordingly. It could also play an important role in limiting the impact on health care services, as well as delaying the outbreak peak time and reducing the outbreak duration.

The research was published today in the journal .

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91ŃÇɫ is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change and prepare our students for success. 91ŃÇÉ«'s fully bilingual Glendon Campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education. 91ŃÇɫ’s campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future. 

Media Contact:

Sandra McLean, 91ŃÇÉ« Media Relations, 416-272-6317, sandramc@yorku.ca

The post Shorter lockdowns could lead to fewer COVID-19 infections appeared first on News@91ŃÇÉ«.