As measles outbreaks continue, is San Joaquin County safe?

With summertime travel picking up, public health officials are again warning how easy it is for measles to spread.

On Monday, Sacramento County health officials reported a case of the highly contagious virus in an unvaccinated child who recently returned from international travel. The infection marks the 16th confirmed case of measles in California this year.

Sacramento County’s health department said the child, who was unvaccinated, was likely exposed to the measles virus before returning to the U.S. The patient sought treatment at a hospital in Carmichael last week and is now recovering at home, health officials said.

Dr. Olivia Kasirye, Sacramento County’s public health officer, said that keeping up to date on your vaccines is one of the most effective ways to protect yourself and those around you. 

“This case shows how easily measles can re-enter our community through international travel,” Kasirye said. “When more people are vaccinated, we all benefit from a healthier, more protected community.”

No additional measles cases have been identified, but lab testing detected measles in wastewater samples collected in late May and early June from the Sacramento Regional Wastewater Treatment Plant, according to a statement issued by the county.

The case has not been directly linked to the wastewater detections, but Sacramento County Public Health uses wastewater surveillance to alert local providers to possible measles activity.

While officials say the latest infection does not pose a risk to the general public, those who were at Mercy San Juan Medical Center while the child was being treated — from 5:11-9:45 p.m. June 10 — may have been exposed.

“The hospital implemented appropriate infection control measures once measles was suspected and alerted public health officials,” the county said in a statement. 

Anyone who was at the hospital during that time should call Sacramento County Public Health’s Communicable Disease Program at (916) 875- 5881. A trained public health team is available to assess individual risk and determine whether preventive steps, including MMR vaccinations, are recommended.

Measles in San Joaquin County

While there have been other measles cases confirmed in Sacramento County and elsewhere in the state, none have been reported in San Joaquin County.

The local health department said its last measles case — in March 2024 — occurred in a child who, like the Sacramento County patient, was exposed to measles overseas prior to arriving in the U.S. The child, who also was unvaccinated, then sought treatment at an urgent care facility.

That case was among 285 confirmed measles infections in the U.S. last year. By comparison, this year’s total, as of Tuesday, was 1,197, according to the Centers for Disease Control and Prevention. 

Measles was declared eliminated from the United States in 2000.

That status was threatened in 2019 when 1,274 measles cases were reported from an outbreak in New York and infections in 30 other states. This year’s surge in cases, fueled by outbreaks in Texas, New Mexico and Kansas, is nearing the high set in 2019.

Despite the rise in cases, Dr. Maggie Park, San Joaquin County Public Health Services’ public health officer, said there isn’t any reason to be alarmed — but she does recommend getting vaccinated. 

“Measles rates have been very low across the nation for many years, and now we’re seeing a resurgence of measles because of vaccination rates that are falling below the desired rates in portions of the country,” Park said. 

She credits high vaccination rates among kindergarteners for the region’s success in keeping measles at bay. 

Elementary school classrooms are where the potential for vaccine-preventable disease transmission is higher, according to the CDC. Since school vaccination assessments help identify pockets of under-vaccinated students, health officials use school-reported data to track vaccination rates. 

“What we’re hoping for is that our level of immunity, especially among children, really gives us some level of protection,” Park said. “We might see a single case here or there, as we did last year, but would not, hopefully, ever have an outbreak.” 

San Joaquin County’s vaccination rates have exceeded requirements to maintain herd immunity among kindergarteners. According to the World Health Organization, herd immunity against measles requires about 95% of a population to be vaccinated, while the Mayo Clinic indicates at least 94% of the population be vaccinated for herd immunity. 

“We know that not to be true, but I think that some of that myth still lingers,” Park said. “And of course, we’re just getting over a pandemic where the COVID vaccination was questioned by certain people.

“I think some of that mistrust still prevails and affects people’s beliefs in vaccinations in general,” Park said. “We’re trying to really go back to the education part of our vaccination campaigns, and get back to where we were pre-COVID with the trust that we have with the community.”

Park said the health department welcomes questions and concerns from the public, but she encourages people to talk to their doctors for information about vaccinations. 

“(Doctors) are the people they’ve built relationships with and who they tend to trust,” Park said. 

What to know about measles

Measles is a highly contagious viral disease. It is widespread in many parts of the world, including Europe, Africa and Asia. 

Symptoms include:

• High fever (may spike to more than 104 degrees)
• Cough
• Runny nose (coryza)
• Red, watery eyes (conjunctivitis)

The onset of symptoms typically begins with a fever that lasts for a couple of days, followed by a cough, runny nose, conjunctivitis (pink eye) and a rash. The rash usually appears first on the face, along the hairline and behind the ears, and then spreads to the rest of the body. 

If one person has measles, up to 9 out of 10 people nearby will become infected if they are not vaccinated, the CDC warns.

Measles cases nationwide 

There have been 21 measles outbreaks resulting in 1,197 cases reported by 35 jurisdictions across the U.S. this year, according to the CDC. Both the CDC and the California Department of Public Health define an outbreak as three or more cases. By comparison, there were 16 measles outbreaks reported in 2024 and only four in 2023.

Of those confirmed cases, 95% involved patients who either were not vaccinated or their vaccination status was unknown, according to the CDC. 

About 12% of this year’s cases resulted in hospitalizations, and there have been three confirmed measles-related deaths.

Measles cases in California  

There have been 16 confirmed cases of measles in California this year, according to the state’s department of public health.

While high levels of immunity in the general population ultimately limit measles outbreaks, the virus readily spreads in communities with lower vaccine coverage. 

From December 2014 to April 2015, at least 131 California residents were infected in a large measles outbreak that was linked to visitors at Disneyland. The outbreak also infected residents of six other states, Mexico and Canada.

In 2019, there were 73 confirmed measles cases in California, including 41 associated with six separate outbreaks. Of those outbreaks, five were linked to patients who had traveled internationally, and one had an unknown source. 

How to stay safe

Anyone who is not vaccinated against measles, one of the most contagious viruses in the world, is at risk, health officials warn. 

The primary measles vaccine is the MMR vaccine. Another vaccine, the MMRV vaccine, also protects against chickenpox. That vaccine is licensed only for use in children 12 months to 12 years old.

Two doses of the MMR vaccine are about 97% effective in preventing measles, while one dose is about 93% effective, according to the CDC. 

However, two doses give lifelong protection and it’s never too late to get your shots, said Dr. Erica Pan, California’s public health officer.

“If you or your loved ones are not up to date with your MMR vaccine, it’s not too late,” Pan said in a video posted on social media.