San Francisco Confirms First Measles Case Since 2019, in an Unvaccinated Infant

Key Points:

• San Francisco has reported its first measles case since 2019, involving an unvaccinated infant exposed to the virus during international travel; the infant is recovering at home and household members are vaccinated.
• California is experiencing one of its worst measles outbreaks since 2019, with 39 confirmed cases this year and ongoing clusters in Placer and Sacramento counties; no deaths have been reported.
• Measles is highly contagious and can cause serious illness, but two doses of the MMR vaccine are 97% effective; infants under 12 months are especially vulnerable since the vaccine is normally administered starting at 12 months.
• Health officials recommend early MMR vaccination for infants as young as 6 months if traveling internationally, and advise all travelers to ensure they are up to date on vaccinations due to global and domestic measles outbreaks.
• Even vaccinated individuals can sometimes contract measles, underscoring the importance of vaccination and awareness of symptoms, especially after international travel.