Measles outbreak in the Philippines: epidemiological and clinical characteristics of hospitalized children, 2016-2019 Fleurette M. Domai, a Kristal An Agrupis, b Su Myat Han, a Ana Ria Sayo, c Janine S. Ramirez, c Raphael Nepomuceno, a Shuichi Suzuki, a,b Annavi Marie G Villanueva, a,c Eumelia P. Salva, c Jose Benito Villarama, c Koya Ariyoshi, d Kim Mulholland, a,e,f,g Luigi Palla, a,h Kensuke Takahashi, a,d,i Chris Smith, a,d,j * and Edna Miranda, c a School of Tropical Medicine and Global Health, Nagasaki University, Japan, 852-8523 b San Lazaro Hospital-Nagasaki University Collaborative Research Office, Manila, Philippines c San Lazaro Hospital, Manila, Philippines d Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan e Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3051, Australia f Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia g Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK h Department of Public Health and Infectious Diseases, University of Rome La Sapienza, Rome, Italy i Acute & Critical Care Unit, Nagasaki University Hospital, Nagasaki, Japan j Department of Clinical Research, London School of Hygiene and Tropical Medicine Summary Background Measles outbreaks increased worldwide during 2017-19. The largest outbreak in the World Health Organisation Western Pacific region occurred in the Philippines where first-dose measles-containing vaccine (MCV1) coverage had reduced to 75% in 2018. The aim of this study was to summarise paediatric measles admis- sions to the national infectious diseases referral hospital in Manila during 2016 to 2019. Methods A retrospective single-centre observational study including 5,562 children aged under five years admitted with measles from January 2016 to December 2019. We summarised sociodemographic and clinical characteristics, vaccine status, reported exposures, and outcomes. Univariable and multivariable logistic regression analyses were undertaken to assess associations between different characteristics of hospitalised children and death. Findings The median age of children hospitalised with measles was 11 months (interquartile range: 7-28). 84¢5% of cases were reported not to have received any MCV. The risk of mortality was 3¢2%, with 41% of deaths occurring among children aged less than 9 months. No children died who had received two MCV. The following characteristics were significantly associated with mortality in the multivariable analysis: age group, residence outside of the national capital region, not having received any MCV, duration between onset of fever and hospital admission of 7-14 days compared with 0-3 days, not receiving vitamin A supplementation, having pneumonia, and gastroenteritis. Interpretation The Philippines remains at risk of future measles epidemics. Routine immunization needs to be strengthened and earlier timing of MCV1 requires further evaluation to reduce measles incidence and mortality. Copyright Ó 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Keywords: measles; vaccine-preventable disease; Philippines, Western-Pacific region; immunisation; paediatric infectious diseases Introduction Measles is a highly contagious viral disease that has been responsible for the death or disability of millions of children. 1,2 Measles incidence and mortality has declined over the past century due to improved nutri- tion, socioeconomic status, healthcare, and the intro- duction of a safe, cost-effective vaccine in the 1960’s. Annual incidence declined from around 4 million in 1981 to less than 150,000 in 2016 leading to renewed interest in global eradication. 3 However, global measles immunisation coverage has been stagnant for a decade *Corresponding author: Chris Smith, School of Tropical Medi- cine and Global Health (TMGH), Nagasaki University, 1-12-4 Sakamoto, 852-8523, Japan, Phone: +81 (0)80-8710-5309 E-mail address: christopher.smith@lshtm.ac.uk (C. Smith). The Lancet Regional Health - Western Pacific 2021;19: 100334 Published online xxx https://doi.org/10.1016/j. lanwpc.2021.100334 www.thelancet.com Vol xx Month xx, 2021 1 Articles