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Investigating risk factors contributing to COVID-19 infections

November 22, 2021
With funding from IDRC, a research team from the Prospective Urban Rural Epidemiology (PURE) study, a large international population research effort coordinated by McMaster University’s Population Health Research Institute (PHRI), is studying why some people get COVID-19 and others do not.
A photo of the PURE team at a meeting in India in 2017.
PURE investigators meeting, New Delhi, India, 2017

In addition to investigating risk factors for a SARS-CoV-2 infection in low-, medium- and high-income countries, they are looking at the financial effects of the pandemic. Darryl Leong, a scientist at PHRI, leads this PURE COVID-19 sub-study. 

To date, the team has collected information from 30,000 adults in 19 countries (Argentina, Brazil, Canada, Colombia, Ecuador, India, Kyrgyzstan, Kazakhstan, Malaysia, Philippines, Poland, Russia, Saudi Arabia, South Africa, Sweden, Tanzania, Turkey, United Arab Emirates, Zimbabwe) on five continents. Blood samples have been obtained from 5,000 of these individuals, with blood collection continuing in hopes of gaining approximately 10,000 specimens. All of the specimens will be tested to see if the individuals were infected with the SARS-CoV-2 virus without knowing it (asymptomatic).  

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Map of countries
PURE
Countries participating in the overall PURE study

Early results show that obesity is one of the most important risk factors for a COVID-19 infection. The team also found that the pandemic had the greatest financial impact on people in low-income countries, while people in high-income countries experienced less of a financial impact. In future analyses, the late complications of a SARS-CoV-2 infection, such as long-lasting lung problems, loss of muscle strength, heart failure or other diseases, will be the focus of a comparison between participants who experienced a COVID-19 infection and controls in the same communities. The study will continue for a further 12 months or longer depending on the course of the pandemic.