UPDATED – 08/07/26 – The number of measles cases has jumped in the First State. Delaware Public Health officials have now confirmed 20 cases – all the positive cases are in Kent County. ===================================================================ORIGINAL STORY – 08/01/26 – Delaware Public Health officials now report 8 cases of measles in Delaware. Maryland has confirmed 12 measles cases in 2026. Testing shows the MMR vaccine to be 97% effective at preventing measles for those who have received two doses of the MMR vaccine and are not severely immunocompromised.