Effectiveness of a Fourth Dose of COVID-19 mRNA Vaccine Against Omicron Variant Among Elderly People in Singapore

Affiliations

• ¹ Ministry of Health, Singapore.
• ² Ministry of Health, and National Centre for Infectious Diseases, Singapore.
• ³ Ministry of Health, and Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
• ⁴ Ministry of Health, and Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
• ⁵ National Centre for Infectious Diseases, Yong Loo Lin School of Medicine, National University of Singapore, Lee Kong Chian School of Medicine, Nanyang Technological University, and Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore.