San Bernardino County health officials have confirmed the county’s first measles case, saying an unvaccinated minor visiting from another state tested positive. The child spent time at the Walmart Supercenter on Mountain Avenue in Ontario on Jan. 29, and anyone who was in the store between noon and 3 p.m. may have been exposed.
According to NBC Los Angeles, the San Bernardino County Department of Public Health identified the exposure window and cautioned that unvaccinated people, pregnant people and those with weakened immune systems should be especially watchful. Officials are urging anyone who was at the store during that time to review their vaccination records and contact a healthcare provider if they notice symptoms.
Where the Exposure Happened and Recent County History
County records show the last reported measles case in San Bernardino County was in January 2024, when an international traveler tested positive. Public health investigators say they are now tracing contacts from the Ontario visit and working with the Walmart store to identify staff and customers who might have been exposed. As outlined by the San Bernardino County Department of Public Health, vaccine clinics and school-based immunization events are available for residents who need to catch up on missed measles shots.
Symptoms, Timing and Post-exposure Options
The Centers for Disease Control and Prevention says measles symptoms typically appear 7 to 21 days after exposure and usually start with fever, cough, runny nose and red, watery eyes, followed by a characteristic rash. The CDC also notes that an MMR vaccine given within 72 hours of exposure can prevent or lessen illness. Immune globulin may be offered within six days of exposure for infants, pregnant people and those who are immunocompromised.
Part of a Wider California Measles Uptick
The California Department of Public Health issued a health alert this week about an increase in measles cases across the state, urging clinicians to consider measles in patients who show up with fever and rash. In a separate notice, the Orange County Health Care Agency confirmed that an infectious traveler visited Disneyland Resort on Jan. 28, prompting exposure warnings for the theme parks and other public locations…