Scientists from the Ministry of Health in Jerusalem, Israel document unusually high numbers of measles cases and high case-fatality rates (CFRs) in children—especially in six neighborhoods populated with ultraorthodox Jews—during an outbreak in the city in 2025-26.

Jerusalem is the largest city in Israel, having a population of roughly 1 million in 2025 (10.2% of the population of Israel), comprising about 62% Jewish and 38% Arab people. Of the Jewish population, an estimated 50.0% are ultraorthodox Jews. 

Uptake of the first measles, mumps, and rubella (MMR) and the MMR plus varicella (MMRV) vaccines among children aged 1 to 6 years in Jerusalem fell from 94.7% in 2019 to 78.3% in 2024 and is the lowest in Israel, the authors noted.

Coverage in April 2025 ranged from 99.4% among Arab children in East Jerusalem to 55.0% in six designated neighborhoods in central Jerusalem, which has a population of about 67,500, mostly ultraorthodox Jews.

The researchers’ findings were published yesterday in Emerging Infectious Diseases.

The reported measles infection rate in Jerusalem from April 2025 to March 2026 was 129.2 cases per 100,000 people—15 times higher than in the rest of Israel. 

Of 1,289 measles patients from April 2025 to March 2026 in Jerusalem (36.1% of the 3,574 cases reported in Israel), 11 children died, for a pediatric CFR of 0.9% in Jerusalem, compared with 0.3% elsewhere in the country, 0.3% to 5.3% in low- and middle-income countries, 0.2% to 0.3% in the United States, and 0.1% in Europe. 

The median age of children who died was 1.4 years; 72.7% were boys. Ten of the 11 children were otherwise healthy; nine of them were younger than 3 years, hadn’t received any vaccinations, and weren’t registered in mother/child health clinics. One 7-year-old child who died had a known serious congenital heart abnormality and had received a single MMRV dose at 1 year of age but didn’t receive the second dose.

The overall measles death rate in Jerusalem was 1.1 deaths per 100,000 people, compared with 0.04 deaths/100,000 in Europe to 2.2 deaths/100,000 in Africa. Among children younger than 5 years in Jerusalem, the measles death rate was 7.7 deaths/100,000 but 80.1 deaths/100,000 in six neighborhoods populated by ultraorthodox Jews, and the measles-attributed death fraction compared with all-cause deaths the previous year was 47%.

The authors noted a 2018-19 measles outbreak in Israel that sickened 4,290 people. Of those cases, 1,415 (33.0%) were in Jerusalem residents, and two people died, for a CFR of 0.1% and a measles death rate of 0.2 deaths/100,000. 

The median age of measles patients in Jerusalem was 3.1 years, and 70.7% of patients were younger than 5 years. Median household size was six, and 95.4% were unvaccinated against measles, while 4.6% received a single dose. Most patients (68.7%) lived in the six neighborhoods, home to 6.8% of Jerusalem’s under-5 age-group, but 71.9% of patients younger than 5 years in Jerusalem were from the ultraorthodox neighborhoods.

Longer follow-up on children recovering from measles might identify additional cases of measles illness and death.

The median household size of patients who died was seven, and one to three other family members reportedly had measles. The median time from the first measles symptom (fever or rash) to emergency department (ED) visit was eight days, and death occurred within 15 days. 

Six children were dead on arrival at the ED, and five were hospitalized for a median of 21 days; of them, three received extracorporeal membrane oxygenation. Eight patients (72.7%) had radiologic evidence of pneumonia on chest radiograph at admission, and six had blood cultures positive for pneumonia.

Secondary infection due to immune suppression and immune amnesia might have contributed to severe outcomes, the researchers said. “Longer follow-up on children recovering from measles might identify additional cases of measles illness and death,” they wrote. “That explanation is supported by the large number of case-patients who had bacteremia among all fatal cases (6 of the 11 children who died), whereas 2 were infected with vaccine-preventable pathogens.”

“Given the measles first-vaccine coverage of 55% in the 6 neighborhoods at the beginning of the outbreak, combined with MMR vaccine efficacy of 95% at 12 months, an estimated 47.7% of infants in each birth cohort were unprotected against measles,” the authors wrote.

Given the measles first-vaccine coverage of 55% in the 6 neighborhoods at the beginning of the outbreak, combined with MMR vaccine efficacy of 95% at 12 months, an estimated 47.7% of infants in each birth cohort were unprotected against measles.

The number of patients who were dead on arrival in the ED might reflect avoidance of healthcare in ultraorthodox communities due to distinct cultural, religious, and social considerations and insularity from government and secular media, the authors hypothesized. 

Other factors possibly contributing to vaccine hesitancy include mistrust of government, frustration with the COVID-related pandemic restrictions, and skepticism about the MMR and MMRV vaccines.

“The young age of the unvaccinated measles case-patients, in addition to overcrowding and the presence of other sick household members, increased domestic measles transmission because of higher in-house viral inoculum and repeated exposures,” the authors wrote. “In response, the Ministry of Health recommended MMR vaccine in Jerusalem at 6 months because maternal antibodies wane over time.”

Efforts to vaccinate during an outbreak should be followed by continuous maintenance of coverage, they said. “Culturally tailored interventions, developed in partnership with community leaders, are needed to strengthen trust in healthcare providers and vaccines, promote earlier healthcare-seeking among parents to enable timely recognition and medical assessment, reduce the risk for delayed diagnosis, and prevent clinical deterioration,” they concluded.