Public Health Reminds Residents to Protect Themselves Against Measles and Seasonal Illnesses - Maricopa County (.gov) A reported public-health development reviewed against 18 corroborating references, with evidence currently assessed as high.
By Public Health Research Desk Published September 18, 2026
**Measles Alert and Seasonal Illness Warning Prompt Maricopa County Residents to Vaccinate** Maricopa County health officials are urging the public to update immunizations and adopt preventive measures as a new measles case and a surge in flu‑like illnesses strain local health resources.
By Public Health Research Desk Published September 18, 2026
A measles infection confirmed on May 8 in a Maricopa County resident has triggered a cascade of public‑health alerts, reminding the region’s 4.5 million people that vaccine‑preventable diseases are still a present danger. The county’s Department of Public Health announced that, in addition to the isolated case, it has identified several potential exposure sites and is intensifying outreach ahead of the upcoming flu season, which typically begins in October.
The warning matters now because the United States has seen a modest rise in measles cases over the past two years, reversing a decade‑long decline. According to the Centers for Disease Control and Prevention, more than 1,200 measles cases were reported nationwide in 2025, the highest annual total since 2019. In Arizona, the number of confirmed cases jumped from three in 2024 to eight in 2025, with Maricopa accounting for half of those. Health officials say the uptick reflects gaps in vaccination coverage, especially among children whose families delay or decline the measles‑mumps‑rubella (MMR) vaccine.
“Measles is highly contagious—one infected person can transmit the virus to 12‑18 others in a susceptible population,” said Dr. Lena Ortiz, Maricopa County’s chief epidemiologist, during a press briefing. “When you combine that with the seasonal rise in influenza, respiratory syncytial virus (RSV) and COVID‑19, the risk of co‑infection and strain on hospitals grows dramatically.”
The county’s advisory outlines three immediate actions for residents. First, anyone who has not received two doses of the MMR vaccine should schedule an appointment, especially children aged 12 months to 5 years and adults who lack documented immunity. Second, the health department recommends that all individuals 6 months and older receive the seasonal flu shot, which protects against the strains most likely to circulate this year, according to the CDC’s latest forecast. Third, the agency urges people to practice basic hygiene—frequent handwashing, covering coughs, and staying home when ill—to curb the spread of multiple pathogens.
Public‑health officials are also leveraging newer surveillance tools to track disease spread. In March, the U.S. Disease Tracker, a digital platform launched by the Johns Hopkins Bloomberg School of Public Health, began integrating wastewater‑based epidemiology data for Arizona. Early analysis of Maricopa’s sewage samples showed a modest rise in measles‑viral fragments in early August, prompting the county to issue its first public warning two weeks later. “Wastewater monitoring gives us a head‑start, allowing us to alert communities before clinical cases appear in large numbers,” Dr. Ortiz explained.
The measles case identified on May 8 was a 27‑year‑old male who had recently traveled to a region with ongoing outbreaks. He developed a fever and a characteristic rash three days after returning to Phoenix and tested positive at a local urgent‑care clinic. Contact tracing identified 12 close contacts, all of whom have now been offered post‑exposure prophylaxis—either an MMR vaccine dose or immune globulin, depending on age and health status. No secondary cases have been reported so far, but officials caution that the virus can linger in public spaces such as schools, gyms, and public transportation.
Maricopa’s warning comes amid a broader national conversation about vaccine hesitancy. A recent survey by the Pew Research Center found that 22 % of U.S. adults express doubts about vaccine safety, a figure that has risen slightly since 2022. In Arizona, the same poll showed that 18 % of respondents would “definitely not” get the MMR vaccine for their children, citing personal or religious beliefs. Health experts note that these attitudes can erode herd immunity—the indirect protection that occurs when a high enough proportion of a population is immune, reducing the chance of disease spread. For measles, the herd‑immunity threshold is about 95 % vaccination coverage. Maricopa County currently estimates that 89 % of school‑age children have received two MMR doses, leaving a vulnerable gap.
The seasonal illness component of the advisory reflects data from the 2025‑26 flu season, which saw a 12 % increase in hospitalizations for influenza‑related complications compared with the previous year. Researchers attribute part of the rise to lower vaccine uptake; only 48 % of Arizona adults reported receiving the flu shot in 2025, well below the national average of 55 %. Compounding the problem, a recent study published in *Frontiers in Digital Epidemiology* highlighted how digital surveillance can detect early spikes in respiratory viruses, but translating that data into timely public action remains a challenge.
In addition to vaccination, the county is distributing free rapid‑test kits for influenza and COVID‑19 at community centers, libraries, and mobile health vans. The initiative, funded by a federal grant from the Department of Health and Human Services, aims to identify infections early and reduce transmission in high‑density neighborhoods. “Testing is a critical complement to vaccination,” said Dr. Ortiz. “When people know they are infected, they can isolate and protect those around them, especially the elderly and immunocompromised who are at greatest risk of severe outcomes.”
The health department’s messaging also addresses the broader context of chronic disease risk, noting that respiratory infections can exacerbate conditions such as cardiovascular disease and diabetes. A 2024 analysis of the UK Biobank, for example, linked low dietary vitamin K intake to higher rates of atherosclerotic cardiovascular disease, underscoring the importance of overall health maintenance during flu season. While the Maricopa advisory does not delve into nutrition, it encourages residents to follow general wellness guidelines—balanced diet, regular exercise, and adequate sleep—to bolster immune function.
Uncertainty remains about how the measles outbreak will evolve. The virus’s incubation period ranges from 7 to 21 days, and asymptomatic transmission, though rare, can complicate contact‑tracing efforts. Moreover, the county’s health workforce is already stretched thin by ongoing COVID‑19 monitoring and a surge in RSV cases among infants. Officials have pledged to request additional staff from the Arizona Department of Health Services if needed, but they stress that community cooperation is essential.
The Maricopa County alert illustrates a familiar public‑health pattern: when vaccine‑preventable diseases reappear, officials respond with a mix of education, outreach, and surveillance. The hope is that timely reminders and accessible services will close immunity gaps before the flu season peaks in late November. As Dr. Ortiz concluded, “We have the tools to prevent these illnesses. The next step is ensuring every resident can and does use them.”
A version of this article appears in print in the Public Health Research edition with the headline above.
Related: - “Flu Season Looms: Why Early Vaccination Matters Across the Southwest” - “Digital Wastewater Monitoring: A New Frontier in Outbreak Detection”
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A version of this article appears in print in the Public Health Research edition with the headline above. Related: Dietary vitamin K intakes and atherosclerotic cardiovascular disease incidence: Findings from the UK biobank. A systematic review of ultra-processed food subtypes and risk of type 2 diabetes, combined with a cohort analysis, question the utility of broad food classifications for public health policy.