Quick Take
Preventable diseases are making a troubling comeback in Santa Cruz County, with whooping cough cases already rising to 33 this year already and measles spreading across California. Most of the cases are starting in middle and high schools, write local pediatric providers. They warn that declining vaccination rates and missed boosters are leaving children, especially infants, vulnerable. The risks of these highly contagious illnesses are real, they write, and stress routine immunizations remain the strongest defense. The moment is urgent: Staying up to date on vaccines will protect us all.
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As pediatric health providers serving Santa Cruz County, we are writing with a message we wish we did not need to send: Two diseases that are largely preventable are threatening our community right now, and the trends are heading in the wrong direction.
The first is whooping cough, or pertussis. It’s back and is surging locally. The Santa Cruz County public health department issued an early health advisory on March 4, when the confirmed cases for the county were only eight. In recent communications, the Health Services Agency shared that Santa Cruz County has recorded 33 confirmed cases since Jan. 1, compared to a total of 35 cases for all of 2025, which was already an above-average year.
If this pace continues, 2026 will be worse than 2019, when we had over 100 cases countywide.
Right now, 75% to 80% of our local cases are in middle and high school students. Whooping cough causes severe, prolonged coughing fits, difficulty breathing and in the most vulnerable, especially babies under 3 months old, it can be fatal. It is also extraordinarily contagious: About 80% of susceptible household contacts will get infected if one family member brings it home.
Vaccination is our best defense. Children should receive the full five-dose DTaP (diphtheria, tetanus and pertussis) series starting at 2 months. But here is something many parents do not know: Timely routine boosters are very important as vaccine immunity wanes over time. A Tdap (tetanus, diphtheria and pertussis) booster is needed at age 11-12 years, and adults need a booster every 10 years. When we see vaccinated teens and adults getting sick, it is often because their immunity has faded not because the vaccine failed.
Staying current on boosters closes that gap. If you are worried about your immunity waning, check with your doctor.
Measles has also returned to California, and we are not immune. Santa Cruz County has not yet recorded a measles case in 2026, but we cannot be complacent.
California has already seen 46 cases this year, with active outbreaks in Placer, Riverside and Shasta counties. Nationally, the United States has recorded 1,714 measles cases in 2026 alone, nearly matching the unprecedented total for all of 2025. Ten outbreaks are currently active across the country.
Measles is not a mild inconvenience.
Before the vaccine was available, it caused approximately 500 deaths, 48,000 hospitalizations, and 1,000 cases of encephalitis (swelling of the brain) in the U.S. each year. It remains one of the most contagious diseases known. The virus can linger in the air or on surfaces for two hours after an infected person has left a room.
Currently, 96% of current U.S. cases are in unvaccinated individuals.
The MMR (measles, mumps and rubella) vaccine is safe, effective and available. Children should receive their first dose at 12 to 15 months and a second dose at 4 to 6 years. Please make sure your child is up to date; if you are unsure, call your pediatrician’s office and ask. The most recent data available from the California Department of Public Health showed the MMR vaccination rate for kindergarten students in Santa Cruz County to be 91.8% for the 2023-24 school year. Reports indicate this rate slipped further to roughly 91.1% for the following 2024-25 school year, remaining well below the 95% threshold needed for herd immunity.
It is also lower than the California and national averages.
This is a moment that calls for action.
We understand that parents today are navigating a noisy information environment. Questions about vaccine safety are understandable, and we welcome them. But the science is clear and extensive: Vaccines do not cause autism. Side effects are real but almost always mild and temporary. The risks of these diseases include brain damage, hospitalization and death, which are far greater than the risks of the vaccines that prevent them.
When you vaccinate your child, you are not only protecting them. You are protecting the infants too young to be vaccinated, the immunocompromised neighbors who cannot receive live-virus vaccines and the older adults whose immunity has faded. Vaccination is one of the most powerful acts of community care available to any family.
If you or your child is due for a DTaP, Tdap or MMR vaccine, or if you’re not sure, please contact your pediatrician. Do not wait for a case to appear in your school or your neighborhood.
The time to act is now.
The Santa Cruz County Pediatric Health Workgroup is a collaborative of pediatric providers that includes 10 healthcare professionals from local clinics, hospitals and community-based organizations as well as representatives from the Santa Cruz County Health Services Agency and Santa Cruz County Office of Education. It is facilitated by the Health Improvement Partnership of Santa Cruz County.