Between December 1, 2023 and January 23, 2024, CDC was notified of 23 confirmed U.S. cases of measles They included seven direct importations of measles by international travelers and two outbreaks with more than five cases each. Most of these cases were among children and adolescents who had not received a measles-containing vaccine (or MMRV), even if age eligible.
Due to these recent cases, healthcare providers should be on alert for patients who have (1) febrile rash illness and symptoms consistent with measles such as cough, runny nose, or conjunctivitis and (2) have recently traveled abroad, especially to countries with ongoing measles outbreaks. Infected people are contagious from four days before the rash starts through four days afterwards.
Measles cases often originate from unvaccinated or undervaccinated U.S. residents who travel internationally and then transmit the disease to people who are not vaccinated against measles. The increased number of measles importations seen in recent weeks is reflective of a rise in global measles cases and a growing global threat from the disease.