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Confirmed cases of COVID-19 have been tracked closely throughout the pandemic – but they represent only a fraction of the total number of people who have been infected by SARS-CoV-2.

That’s why Tingting Yan, a master’s student at the University of Toronto’s Institute of Health Policy, Management and Evaluation (IHPME) at the Dalla Lana School of Public Health, decided  with Rahul Arora, a Rhodes Scholar and PhD candidate in biomedical engineering at the University of Oxford.

The online tool aims to more accurately depicts global COVID-19 infections by tracking serology tests that look for COVID-19 antibodies in a person’s blood, which indicates a prior infection or vaccination.

“Diagnostic testing is like the tip of the iceberg,” says Yan, who is in IHPME’s system leadership and innovation program. “Serosurveys show what is underneath the surface – COVID infections that weren’t severe enough for testing, people with COVID-19 who didn’t have access to testing and asymptomatic infections where people didn’t even know they had an immune response to COVID.”

The dashboard monitors and synthesizes studies from governments and research organizations to track seroprevalence data – the percentage of people in a population who have SARS-CoV-2 antibodies. The platform visualizes antibody estimates on a map and allows users to compare differences in past exposure between countries, demographic groups and occupations.

The idea for SeroTracker was born out of Yan and Arora’s desire to contribute to Canada’s long-term pandemic response. The pair reached out to ��˾��ֱ�� Professor and President Emeritus David Naylor, who in turn connected them with Tim Evans, executive director of Canada’s COVID-19 Immunity Task Force. They were advised what was needed was a repository of global antibody testing information that was accessible and searchable to monitor the evolution of the pandemic.

Yan and Arora mobilized a team with diverse backgrounds including data science, engineering, medicine, epidemiology and management consulting.

“SeroTracker is mostly driven by graduate and professional students, and keen and talented undergrad students. We are coast-to-coast very proudly Canadian-founded and Canadian-led,” says Yan, noting the contributions of Niklas Bobrovitz, a ��˾��ֱ�� medical student whose expertise in epidemiology – he has a PhD in clinical epidemiology from Oxford –has advanced the team’s research.

To date, the tool has reviewed nearly 3,000 serosurveys from 116 countries and territories. The SeroTracker team has published the largest global systematic review of serosurveys to shed light on global patterns of infection and communities that are disproportionately affected by COVID-19.

Yan says it has been gratifying to provide a tool that has been useful to policy-makers and public health officials in making evidence-informed decisions.

“We make this data available to different people for their purposes and that makes it more of a collaborative project,” she says.

The Public Health Agency of Canada and the World Health Organization used the platform to develop global models of disease spread. The Bill and Melinda Gates Foundation looked at SeroTracker data to guide investment in serosurveys in low- and middle-income countries. Publications such as The Economist referenced the website to estimate excess deaths from COVID-19, while the New York Times examined the site’s seroprevalence data to look at the true toll of the pandemic in India.

Yan and her team are now looking beyond COVID-19 to determine how the platform could be used in other scenarios involving different diseases. They recently received a grant from the Canadian Medical Association Joule Innovation Fund to work on machine learning algorithms that can predict whether an abstract will be included in a search to make the process more efficient.

Yan says developing the platform has been a rewarding experience, allowing her to contribute to the global pandemic response.

“[Working on SeroTracker] gave a really cool community and a real purpose to work towards.”

SeroTracker is funded by Canada’s COVID-19 Immunity Task Force through the Public Health Agency of Canada, the World Health Organization, Canadian Medical Association Joule Innovation Fund and Robert Koch Institute.