In the years leading up to 2020, notable progress had been made on childhood vaccination rates in California. But during the pandemic that progress was reversed, and the recovery since then has been slow.
While rates around the Bay Area continue to be higher than the state overall, in Santa Cruz County just over 91% of kindergarten students had received the recommended doses of the vaccine that provides immunity to the measles virus, according to data released this month from the California Department of Public Health.
Sonoma County is right at the threshold, but every other Bay Area county has higher than the statewide vaccination rate, though some local counties have increased their rates in the past two years, others have dropped. Alameda county has seen MMR vaccine rates drop nearly a percentage point in two years, while rates in San Francisco and Contra Costa have increased the last two years.
For the 2023-2024 school year, California schools reported that 96.2% of kindergarten students were vaccinated against the measles — a slight drop from the previous school year, when it was 96.5%, and lower than two years before when it was 96.3%.
California’s rates are still well above the nationwide average, which was estimated by the Centers for Disease Control and Prevention to have dropped to 92.7% for this past school year. The recommended threshold for vaccination coverage to prevent a measles outbreak is 95%.
Santa Cruz County deputy public health officer Dr. Karissa LeClair Cortez said numbers for the current school year in the county indicate another slight drop, to 91.1%, though data for all counties is not yet available from the California Department of Education.
“For any schools that have more than 10% of students that are conditionally admitted or overdue for immunizations, we reach out to those schools and actually do visits there to provide guidance, resources and support,” LeClair Cortez said. She also said Santa Cruz County has more students doing independent study, who aren’t required to get vaccinated, than other nearby counties, which could contribute to the low rate.
“We do worry that children and the community are at risk because of these low vaccination rates,” LeClair Cortez said. “We know that it’s out there, it’s a matter of when it will come to our local community, unfortunately.”
It’s been over five years since the county’s last measles case, in 2019, but with measles spreading quickly in several active outbreaks around the country, the chances of it finding its way there are higher now. And there is an ever-present risk of travelers bringing it back from places where it has yet to be eradicated.
In December 2014, there was a serious measles outbreak that started at Disneyland. Over 100 cases were associated with that outbreak, the vast majority among the unvaccinated.
The response to the Disneyland outbreak contributed to a steep increase in vaccination rates among California kindergartners over the following years. Several laws, many authored by former state senator Dr. Richard Pan, encouraged vaccination and limited families’ legal recourses for avoiding otherwise-mandatory vaccinations.
The vaccination rate statewide was 96.5% the year the pandemic hit, up from the low 90’s in the early 2010’s. Then schools closed, and the pandemic disrupted the health care system.
“Of all the vaccine preventable diseases, measles is kind of the canary in the coal mine, because it’s the most contagious of all of them,” Pan said. He is now a lecturer of public health and health policy in the Department of Public Health Sciences at UC Davis.
Hundreds of thousands of measles cases were reported each year before the vaccine was introduced, leading to tends of thousands of hospitalizations, and 400-500 deaths a year.
But after decades of vaccination campaigns, in 2000 measles was declared eliminated in the U.S.
“I’m really concerned that we’re going to lose that measles elimination status,” Pan said.
This year’s outbreak in Texas has contributed to two measles deaths, one confirmed and one under investigation still, the first in the country in over a decade. Over 300 cases are associated with the Texas outbreak so far, 23 reported in Kansas in recent days, and 10 in Ohio.
With all these cases circulating, “then what happens is the wildfire catches,” Pan said. To avoid a measles wildfire growing out of control “you clear the brush, you protect zones, that’s what vaccination is about.”
Several sparks have landed in California so far this year, with eight measles cases reported already, according to this week’s update from the state health department. All the reported cases have been related to travel, and none have yet to lead to local spread, though officials reported possible exposures at Los Angeles International Airport early this month, and in a high school and emergency room in Tuolumne County recently.
“In the long run, people realize the value of vaccination,” Pan said. “The problem is, how many people have to die or become disabled before that message finally sinks in?”