The 2019 measles outbreaks refer to a substantial global increase in the number of measles cases reported, relative to 2018.[1] As of April 2019, the number of measles cases reported worldwide represented a 300% increase from the number of cases seen in the previous year, constituting over 110,000 measles cases reported in the first three months of 2019.[1][2] In the first half of 2019, the World Health Organization received reports of 364,808 measles cases from 182 countries, up 182% from the same time period of 2018 when 129,239 confirmed cases were reported by 181 countries.
In the United States, the number of measles cases was set to reach a 25-year high by the middle of the year,[3] beginning with a large concentration of cases in the Pacific Northwest followed by another in New York,[4] as well in the U.S. state of California with two quarantines ordered at two colleges in Los Angeles on April 28, 2019.[5] Other countries reporting large increases included Brazil, Nigeria,[6] Israel,[7] Ukraine, Madagascar, India,[3] and the Philippines. However, the largest and most fatal outbreak of measles in 2019 occurred in the Democratic Republic of the Congo.[8] Other notable outbreak locations include the 2019 Kuala Koh measles outbreak,[9] 2019 Philippines measles outbreak in Asia;[10] the 2019 Pacific Northwest measles outbreak[11] and 2019 New York measles outbreak in the United States;[12] 2019–2020 New Zealand measles outbreak,[13] and 2019 Samoa measles outbreak in Oceania.[14]
In some countries, this outbreak has been fueled by lack of access to the measles vaccine, while in others it has been exacerbated by opposition to vaccination.[1] As one such example, the outbreak in the Philippines was attributed by Health Secretary Francisco Duque III to lowered trust in the government's immunization drive due to a controversy regarding administration of a dengue vaccine.[15] The outbreak prompted President Donald Trump to shift away from his previous skepticism regarding vaccination, and to insist that parents must vaccinate their children.[16] The Trump Administration also took a forceful position of requiring vaccination, with Trump's Surgeon General Jerome Adams calling for limitations on exemptions to vaccination.[17]