[SÃO PAULO, SciDev.Net] Countries in Latin America are facing an urgent call to action as they grapple with the highest number of measles cases recorded in over two decades. A concerning combination of low vaccination rates and increased travel during the FIFA World Cup has contributed to the resurgence of this highly contagious disease, particularly threatening the health of children.
Measles, though preventable through vaccination, presents a significant public health challenge. The Pan American Health Organization (PAHO) has reported that immunization coverage in the Americas is alarmingly below the threshold necessary to protect the population. As of 2026, the region has already documented more confirmed measles cases than it has in the last 22 years.
“Measles leaves no room for complacency. Each outbreak highlights immunity gaps that must be addressed urgently.”
— Daniel Salas, executive manager of the special programme for comprehensive immunisation, PAHO
From January to August of this year, over 51,000 cases of measles were reported across Latin America, a figure that is nearly triple the number recorded throughout 2025, which was 15,152. This surge led to the region losing its measles-free status, highlighting the pressing need for robust communication and action among health authorities.
In a recent advisory, PAHO underscored the importance of enhancing vaccination efforts, improving epidemiological surveillance, and ensuring rapid responses to measles outbreaks, given the “very high” public health risk posed by the disease.
World Cup Fever
Notably, Guatemala, Mexico, the United States, and Peru are currently experiencing the highest rates of measles, collectively accounting for an astonishing 95 percent of the reported cases in the region so far this year. In the U.S. alone, there have been 39 new outbreaks and 3,471 confirmed cases by mid-September, as stated by the Centers for Disease Control and Prevention (CDC).
Public health experts suggest that the decline in vaccination rates, exacerbated by high levels of travel during the June-July World Cup—which took place across Mexico, the U.S., and Canada—has significantly aided the virus’s resurgence. Professor Bianca de Oliveira Cata Preta from the Federal University of Paraná in Brazil explained, “The combination of these factors is what seems to have favoured the spread of the virus, giving rise to the scenario we have now.”
Measles is notably one of the most contagious diseases affecting humans, with one infected individual capable of infecting 12 to 18 others. Cata Preta emphasized that “the high mobility associated with international travel and mass events are factors that can favour the spread of the virus within and between countries.”
To combat this alarming trend, PAHO has committed to closely monitoring the situation across all countries experiencing sustained measles transmission and is aiding affected nations in bolstering surveillance, swiftly detecting, and responding to cases, as well as addressing gaps in vaccination coverage.
Low Vaccination Coverage
Statistics reveal a worrying correlation between the surge in measles cases and vaccination rates. Nearly 73 percent of confirmed measles cases in the Americas this year were among individuals who had not received the measles vaccine, according to PAHO. Many of the remaining cases lacked information on vaccination status, indicating a significant gap in health records and awareness.
Countries across the Americas are falling short of the 95 percent vaccination coverage needed for effective community immunity, with only 85 percent of the population having received both required doses of the MMR (measles, mumps, and rubella) vaccine. This decline in vaccination coverage is driven by various factors, including restricted access, increased vaccine hesitancy, and a lack of awareness about the risks associated with measles.
Cata Preta advocates for a deeper understanding of the reasons behind low vaccination rates on a country-by-country basis to identify effective strategies aimed at increasing coverage.
Measles is transmitted through respiratory droplets, compelling the need for alarm as it can lead to severe consequences such as high fever, cough, conjunctivitis, and rash. Complications can include pneumonia, encephalitis, blindness, and can even be fatal.
Herd Immunity
According to Renato Kfouri, vice president of the Brazilian Society of Vaccination, vaccination remains the most effective method for preventing and controlling measles outbreaks. “International health authorities recommend that at least 95 percent of the population be vaccinated to prevent transmission,” he stated.
This figure represents the threshold for achieving “herd immunity,” where a large percentage of the population is immune, thereby significantly hindering the disease’s transmission. Kfouri cites Brazil as a model, reporting only 15 cases of measles in the first half of 2026, all of which were imported and controlled before leading to larger outbreaks.
Active immunization efforts and surveillance remain crucial, particularly as the epidemiological landscape in neighboring countries evolves and deteriorates. Maintaining high levels of vaccination coverage is vital in order to protect communities from imported cases of measles.
This article was produced by SciDev.Net’s Latin America and Caribbean edition and edited for clarity.
This piece was produced by SciDev.Net’s Global desk.