World's most infectious disease case found in California after they passed through super spreader hubs

Key Points:

• An adult infected with measles passed through San Francisco International Airport on the morning of Thursday and visited two San Jose grocery stores, Trader Joe's and International Halal Market, later that night, potentially exposing others.
• Health officials warn that measles symptoms, including fever, cough, runny nose, red eyes, and rash, may appear 7 to 10 days after exposure, urging unvaccinated individuals to quarantine and monitor for illness for up to three weeks.
• Pregnant women, infants, immunocompromised individuals, and the unvaccinated should seek immediate medical advice if exposed, and symptomatic individuals are advised to contact healthcare providers before visiting in person to prevent further spread.
• California is experiencing its highest annual measles count in seven years, with 49 confirmed cases as of June 8, nearly double the total for all of 2025, predominantly affecting unvaccinated people under 19 years old.
• Santa Clara County health officials emphasize vaccination as the best defense against measles and are working with state and federal agencies on contact tracing, amid ongoing measles resurgence linked to international travel and low vaccination pockets.