Measles Outbreak and Whooping Cough Deaths in Mexico
Mexico concluded 2025 as the country in America with the most confirmed measles cases, totaling 6,213, and 24 deaths. Additionally, it recorded the highest number of whooping cough deaths, with 72, placing it in fifth place for the number of patients with this disease.
Measles Cases and Deaths
According to the Pan American Health Organization, as of December 27, Canada was second in measles cases with 5,353, and the United States followed with 2,012. Bolivia ranked fourth with 541 cases.
El Economista reported that low vaccination coverage in certain Mexican regions, due to some communities’ refusal to be vaccinated and a decline in national coverage, likely contributed to the measles outbreak, primarily in Chihuahua.
Whooping Cough Cases and Deaths
Mexico ended 2025 with 1,582 confirmed whooping cough cases and 72 deaths. In contrast to measles, the country saw a decrease in whooping cough cases from 2024, with 550 cases reported that year. Between 2015 and 2024, the number of cases never exceeded 1,107.
Affected States and Age Groups
Chihuahua experienced the most severe situation, with 6,232 probable cases and 4,483 confirmed cases resulting in 21 deaths. The tasa de incidencia was 113 per 100,000 inhabitants, significantly higher than the national average.
Jalisco and Durango reported 1,764 probable cases and 574 confirmed cases (2 deaths) and 292 probable cases and 40 confirmed cases (1 death), respectively.
Several states accumulated over 100 confirmed cases in 2025: Guerrero (240), Michoacán (231), Chiapas (173), and Sonora (112).
The primary age group affected was 0-4 years (1,603 cases), followed by 25-29 years (700), 5-9 years (692), and 20-24 years (615).
Measles Severity and Vaccination
Measles is highly contagious, with a single infected person potentially transmitting it to up to 18 others. It can lead to severe complications such as pneumonia, encephalitis, blindness, and death. Outbreaks also disrupt daily life and strain healthcare systems.
Vaccination remains the most effective protective measure. Over the past 25 years, the measles vaccine has prevented more than six million deaths in America and is estimated to have averted around 15 million deaths over the past 50 years. However, in 2024, the regional coverage for the second dose of the measles, rubella, and chickenpox (MRC2) vaccine averaged 79%, far below the necessary 95% to prevent outbreaks. Only 31% of countries achieved a coverage of 95% or higher for the first dose, and just 20% reached that level for the second dose.
Whooping Cough Details
Concentration of Whooping Cough Cases
The states with the highest number of whooping cough cases in 2025 were the Federal District (155), Chihuahua (147), Nuevo León (141), and Aguascalientes (102), accounting for 34.4% of the total cases.
National and State Incidence Rates
The national incidence rate was 1.18 cases per 100,000 inhabitants, with Aguascalientes having the highest rate at 6.69 cases per 100,000 inhabitants, followed by Chihuahua at 3.71 cases per 100,000 inhabitants.
Geographical Distribution and Vulnerable Groups
Only Tabasco reported whooping cough cases. The municipalities with the most cases were Guadalupe, Nuevo León (95), Aguascalientes, Aguascalientes (80), and Juárez, Chihuahua (62), accounting for 14.9% of the national cases.
Whooping Cough Deaths
Of the 72 whooping cough deaths in 2025, 69 involved unvaccinated infants under one year old, and 84.7% were infants under six months old.
