Emergence of influenza B/Victoria in the Micronesian US-affiliated Pacific Islands, spring 2019

Data collected through routine syndromic surveillance for influenza-like illness in the Micronesian United States-affiliated Pacific Islands highlighted out-of-season influenza outbreaks in the spring of 2019. This report describes the data collected through the World Health Organization's Pacific Syndromic Surveillance System for the Commonwealth of the Northern Mariana Islands (CNMI), Guam, the Federated States of Micronesia (FSM) and the Republic of the Marshall Islands (RMI). Compared with historical data, more cases of influenza-like illness were observed in all four islands described here, with the highest number reported in Guam in week 9, CNMI and FSM in week 15, and RMI in week 19. The outbreaks predominantly affected those aged