A team of clinician-scientists from the National University Hospital (NUH); NUS Yong Loo Lin School of Medicine (NUS Medicine); NUS Saw Swee Hock School of Public Health; National University Cancer Institute, Singapore; and National University Heart Centre, Singapore has found that oral hydroxychloroquine (HCQ) and povidone-iodine throat spray were effective in reducing the spread of COVID-19 infection in high transmission settings.

The study findings were published in the International Journal of Infectious Diseases , following a randomised clinical trial conducted among 3,037 healthy migrant workers quarantined in a large multi-storey dormitory in Singapore.

Lead author of the interventional clinical study, Associate Professor Raymond Seet, Senior Consultant, Division of Neurology, Department of Medicine, NUH and Department of Medicine, NUS Medicine said, "This is the first study to demonstrate the benefits of prophylactic, or preventive, therapy with either oral hydroxychloroquine or povidone-iodine throat spray in reducing SARSCoV-2 infection among quarantined individuals living in a closed and high exposure setting. These are existing drugs that are easily available and have known safety profiles. This can represent a viable preventive strategy for individuals living in a closed and high-exposure setting, especially in areas and countries where COVID-19 vaccination is not available or widespread.”

The study is novel in that it includes topical therapy in the form of povidone-iodine administration by throat spray which lowered SARS-CoV-2 infection by 24% (in terms of absolute risk reduction) compared with vitamin C.