Teen is San Diego County’s first measles case of 2025

Contact tracing is underway for an unvaccinated teenager who tested positive Thursday for measles infection after traveling abroad and returning home last weekend through Los Angeles International Airport.

Dr. Seema Shah, medical director of epidemiology and immunization services, a division of the San Diego County Public Health Department, said Friday afternoon that no additional details about the young traveller’s identity, including gender and age, are being shared with the public in an effort to protect the individual’s privacy.

The physician said her office was notified by Rady Children’s Hospital at 3:30 a.m. Thursday and immediately began working to determine who may have been in close contact with the patient, who had developed familiar symptoms.

“I’d say it was a very classic presentation, fever and rash,” Shah said.

It’s the first measles case detected so far this year in San Diego County. Four cases were confirmed in 2024 and all were associated with international travel, according to county records. There were zero cases from 2020 to 2023, and two confirmed in 2019, according to the county’s Communicable Disease Dashboard.

Nationwide, measles has surged, with local outbreaks detected in 14 locations, according to Johns Hopkins University’s measles tracking site. A total of 1,352 cases nationwide through Thursday is said to outpace the rate of infection observed in 2019, the most recent year with substantial outbreaks, when 1,274 measles cases were documented.

The teen, after being tested in Rady’s emergency department, was discharged home. The illness was not deemed severe enough to require hospital admission.

Measles is one of the world’s most contagious circulating viruses. It can remain airborne in closed areas for “up to 2 hours,” according to the U.S. Centers for Disease Prevention.

This ability to linger longer than most public health threats means that local public health departments must be meticulous about identifying anyone who was in shared spaces, such as hospital or medical clinic waiting rooms, when an infected person was present.

The county health department issued a notice Friday afternoon, warning the public of the times and places where they could have been exposed, out of an abundance of caution. Efforts are also made to document who was present through other records on file.

Those locations are:

• Scripps Clinic Torrey Pines Urgent Care, 10710 North Torrey Pines Road, La Jolla, from 8:53 p.m. on Wednesday, Aug. 6, to 12:26 a.m. on Thursday, Aug. 7.
• The Rady Children’s emergency department, first floor from 11:01 p.m. Aug. 6 to 5:21 a.m. Aug. 7.

The indicated times account for the virus lingering for up to two hours after the patient departed.

It is important to identify possible cases as early as possible, because it may take up to 21 days for measles to develop after exposure. Early symptoms include fever, cough, runny nose and red eyes with a distinctive red rash usually appearing one to four days after symptoms start. The disease is considered contagious between one and four days after those early symptoms start.

Shah said that it is too early for an estimate of how many may have been exposed. The standard operating procedure is to make a public announcement as soon a possible to provide enough time for those who are exposed to receive preventive treatment.

For those who are old enough, the measles, mumps and rubella vaccine is the standard preventive measure. The first MMR dose is generally given when a child reaches their first birthday. Those younger than 12 months, Shah said, can receive doses of immunoglobulin, also known as antibodies, which can help the body fight a viral infection, a process those in public health call prophylaxis.

“We’re looking today at who needs post-exposure prophylaxis within the first 72 hours,” Shah said. “Today we’re not adding up total exposure numbers, but we are focusing on the people who are at the hightest risk: infants that are less than a year of age, people who are immunocompromised, people, even adults, who don’t have vaccination status.”