Epidemiology

In the prevaccine era, measles was ubiquitous; the World Health Organization (WHO) reports that major epidemics occurred about every 2 to 3 years, with 30 million infections and over 2 million measles-related deaths globally per year.[2]​ In the US, approximately 500,000 measles infections and 500 deaths were reported annually, with the actual number of cases estimated at 3 to 4 million annually, with more than 90% in children ages under 15 years.[3] Measles vaccine​ was introduced in 1963, leading to a more than 95% reduction in the number of reported measles cases. Epidemics occurred less frequently, affecting a greater proportion of infants, adolescents, and adults. In 2000, measles was declared no longer endemic in the US.

Worldwide, measles remains a common infection. Following a global decrease in 2000 to 2016, reported measles infections increased in all six WHO regions during 2017 to 2019. In 2019, 869,770 cases were reported, the most cases reported since 1996.[4] Estimated global mortality from measles also increased nearly 50%, with 207,500 deaths in 2019. Failure to vaccinate on time with two doses of measles-containing vaccines is suggested as the main cause of these increases.[4] Most morbidity and mortality due to measles occurs in low-income countries with poor health infrastructure.[2]​ Reported measles cases were lower in 2020-2022 worldwide, but WHO and the Centers for Disease Control and Prevention report that progress toward measles elimination continues to decline following disruption of measles campaigns during the COVID-19 pandemic, with only 81% of children receiving their first dose of measles vaccine in 2021 and 84% in 2022.[5][6]​​​​​​ ​

In the US in 2019, 1274 cases were reported, a dramatic rise from 375 cases in 2018 and the highest number of cases reported in the US since 1992.[7]​ The high number of cases in 2019 was reported to be the result of a few large outbreaks linked to travelers returning from other countries where measles outbreaks were occurring; most infections were in unvaccinated people.[7]​ In 2018, WHO reported that measles had rebounded in the WHO European Region.[8] Following a record low of 5273 cases in 2016, over 82,500 children and adults in 47 European Region countries contracted measles in 2018 and 72 children and adults died as a result of the infection.[9] In 2019, WHO announced that four countries in the European Region (UK, Albania, Czechia, Greece) have lost their measles elimination status.[10] From January to October 2023, the WHO European Region reported over 30,000 cases of measles, a 30-fold rise compared to all of 2022 (941 cases).[11]

Use of this content is subject to our disclaimer