Who Should Get a Measles Booster? Infectious Disease Doctors Explain

Key Points:

• Two people in Pennsylvania have died from measles complications, marking the first measles deaths in the state in 35 years, amid a nationwide increase in cases with 2,777 confirmed infections across 47 states as of August 20, 2026.
• Measles cases in 2026 have already surpassed previous years, making it the highest year for measles cases since 1991, with serious complications particularly affecting young children, adults over 20, pregnant people, and immunocompromised individuals.
• The CDC recommends a two-dose MMR vaccine series, which is 97% effective; routine measles boosters are not generally needed for fully vaccinated individuals, as immunity does not wane significantly over time.
• Certain groups may benefit from an additional MMR dose, including those vaccinated between 1963-1967 with an inactivated vaccine, people born before 1989 who received only one dose, and individuals at higher risk due to travel or exposure.
• If vaccination history is unknown, individuals in outbreak areas are advised to get an MMR dose without prior testing, as an extra dose is safe; MMR vaccines are available through primary care providers, pharmacies, and health departments.