Article

Measles

(This page is part of a series. For information on other illnesses that can affect NPS employees, volunteers, commercial use providers, and visitors, please see the NPS A–Z Health Topics index.)
A bar graph depicting the number of U.S. measles cases each year from 2010 to 2022
Number of U.S. measles cases reported by year from 2010-2022

Centers for Disease Control and Prevention
https://www.cdc.gov/measles/cases-outbreaks.html

THE BASICS
Humans: Measles is a highly contagious but vaccine-preventable viral illness. The virus spreads through the air when an infected person coughs or sneezes or through secretions from the mouth. Symptoms can develop from 7 to 21 days after exposure. Symptoms of measles start with a fever, cough, runny nose, and red eyes, followed by a rash that usually begins on the face and spreads to the rest of the body. Measles can cause serious complications, including ear infections, lung infections, diarrhea, brain swelling, and death Measles is especially dangerous for babies and young children. People are considered contagious from 4 days before rash development to 4 days after rash development. Measles spreads from person to person; other animal species do not spread measles.

Measles is common in other parts of the world, including countries in Europe, Asia, the Pacific Islands, and Africa. Worldwide, about 20 million people get measles each year. Outbreaks occur in the U.S. when infections reach communities where groups of people are unvaccinated, including children too young to be vaccinated, as the first dose is not given until after the first year.Full vaccination against measles via two doses of the MMR vaccine (a combined vaccine that also protects against mumps and rubella) provides 97% protection against the virus. CDC considers you protected from measles if one of any of the following criteria are met:
  • You received two doses of measles-containing vaccine, and you are a school-aged child (grades K-12) or you are an adult who will be in a setting that poses a high risk for measles transmission, including students at post-high school education institutions, healthcare personnel, and international travelers.
  • You received one dose of measles-containing vaccine, and you: are a preschool-aged child or you are an adult who will not be in a high-risk setting for measles transmission.
  • Have laboratory confirmation that you had measles at some point in your life
  • Have laboratory evidence of immunity
  • You were born before 1957. If this is the case, it is likely that you have been previously exposed to the virus and are thus immune.
Animals: Most animal species cannot become infected with measles and do not transmit the virus.

Environment: The measles virus can survive in the air after being exhaled for up to two hours. Some studies show that high-intensity UVC lights can be installed in HVAC units and help mitigate the virus.

PREVENTION
  • If you are unprotected against measles, you can talk to your doctor about getting vaccinated.
RESPONSE
  • If you become ill following a potential exposure, contact your healthcare provider and let them know of your concern. Also, please report any confirmed illnesses to the NPS Office of Public Health publichealthprogram@nps.gov as directed in the “Disease Reporting” guidance below.
Last updated: 4/25/2023

Last updated: April 25, 2023