The scientists show that there is a close association between clinical cases of COVID-19 and viral loads in wastewater, with viral loads increasing up to two days before cases were detected.
The Tokyo 2020 Olympic and Paralympic Games were held on July 21 and September 21, 2021, a time when the incidence and spread of COVID-19 was prevalent. Therefore, a rigorous, multi-pronged testing approach was enacted to limit the spread of the virus and allow the Games to proceed.
Following on from previous research, a team led by Associate Professor Masaaki Kitajima from Hokkaido University has demonstrated the association between SARS-CoV-2 viral loads in wastewater and reported cases in the Olympic and Paralympic Village. Their findings were published in the journal JAMA Network Open.
Athletes and support staff from the Olympic and Paralympic Village were tested daily; in addition, wastewater in the sewer system was also sampled and analyzed (wastewater-based epidemiology, WBE) daily for viral loads. The results were reported to the Tokyo 2020 Organizing Committee.
In this study, the authors wanted to examine the association between clinically reported cases and viral loads in wastewater. They correlated the results of 360 samples collected from sewers in 7 distinct areas of the Village with confirmed cases of COVID-19 obtained from the Organizing Committee and with close contact testing data from a previous report.
The researchers found that SARS-CoV-2 was present in 151 sewage samples, 53 from the Olympics and 98 from the Paralympics. The number of confirmed cases was also higher at the Paralympic Games. The strongest correlation between SARS-CoV-2 RNA load in wastewater and the presence of clinically positive areas was found in areas that had peak viral loads in wastewater within three days (two days before the day of the clinically positive area).
The study suggests that WBE and clinical testing are complementary, and that the testing strategy played a role in preventing clusters of COVID-19 in the Village. This study of one of the world’s largest mass gatherings provides novel evidence on the implementation and use of WBEs in communities where all members are tested daily and could be used to track and control clusters of COVID-19 in the future.
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Source: www.sciencedaily.com