On June 15, the Pan American Health Organization (PAHO) issued an urgent alert over a sharp rise in diphtheria cases across Latin America and the Caribbean, calling on member states to strengthen their vaccination programs. Diphtheria is an acute bacterial infection caused by the diphtheria bacterium, and in developed countries, where effective vaccines are widespread, it is close to being eradicated. Now that disease is quietly returning to the region.
The figures tell the story of how serious the situation has become. In the first 21 weeks of 2026 there were 163 confirmed cases and 5 deaths, already more than double the total number of cases for all of 2025. And 159 of those cases, along with all 5 deaths, are concentrated in Haiti. Sporadic cases have also been confirmed in Brazil and Peru.
Why the Surge Now?
Diphtheria can be prevented with effective vaccines, including the DTP combination (diphtheria, pertussis, and tetanus), and Latin America had at one point succeeded in containing it. Yet cases have been coming back. The biggest factor is a decline in vaccination coverage. According to PAHO, more than half of the current cases involve people who were unvaccinated or whose vaccination status is unknown, meaning many of these infections could have been prevented.
Behind the concentration of cases in Haiti lie a deteriorating security situation and the expansion of territory controlled by gangs. As more districts become inaccessible to medical teams and outreach vaccination breaks down, a growing number of children miss their routine immunizations. Infections that a functioning health system could have prevented are piling up in the middle of a humanitarian crisis.
The Weight of What PAHO Is Asking
In its alert, PAHO called on countries to take several concrete steps: to give the primary DTP (diphtheria, pertussis, and tetanus) immunization to at least 95% of children, to deliver boosters at the same level, to strengthen surveillance and build the capacity to rapidly test suspected cases, and to train health workers.
The figure of "at least 95%" is an internationally recognized threshold for herd immunity. But many countries in Latin America and the Caribbean fall short of it, and gaps in vaccination coverage are scattered across the region. The reasons for falling coverage differ from country to country: routine immunization that was disrupted during the pandemic and never fully recovered, migrants and displaced people who have no access to vaccination, and the spread of misinformation and vaccine hesitancy.
The Nature of the Disease
Diphtheria forms a pseudomembrane in the throat and airway, leading to suffocation, cardiac complications, and neurological damage. What makes it so dangerous is that mortality rises sharply when the antitoxin is given too late. High-income countries keep stockpiles of antitoxin, but in resource-poor areas like Haiti, it takes longer for a patient to move from onset to proper treatment. The fact that all 5 of the deaths occurred in Haiti points squarely to this gap in access to treatment.
The sporadic cases in Brazil and Peru illustrate the risk of cross-border transmission through the movement of people. Within the region, no single country can solve an infectious disease on its own. Unless coverage rises across the region as a whole, containment will remain difficult.
My Perspective
As someone who researches assistive-device subsidy systems and has worked in the field as a physical therapist, I read this news less as a "medical problem" than as a "systems problem." Diphtheria has a vaccine, and it has a treatment in the form of antitoxin. Technically, it is a disease we solved long ago. People still die from it because the system that delivers vaccines, and the system that connects patients to treatment once they fall ill, break down on the ground.
From living in Latin America, I came to feel that the strength of a health system is determined not by whether the system exists, but by whether it reaches the people in the worst conditions. In Costa Rica, where I stayed, primary care and immunization were woven into the community, close to where people live, and that is precisely why preventable diseases were being prevented. What is happening in Haiti is, more than a problem of the system itself, the consequence of a security collapse that keeps health workers from reaching the field and halts the everyday work of prevention. The 95% coverage target is not just a number; it is the very question of how many people left behind in the gaps we can manage to reach.
The same is true of much disability and chronic illness: before the "severe outcome" or the "death," there is always a stage of prevention and access. Allocating resources there is quiet, unglamorous work, but it is what saves the most lives, and seeing this news reminded me of that all over again.
Glossary
difteria (diphtheria) = an acute bacterial infection that forms a pseudomembrane in the throat; it can be prevented by vaccination. antitoxina (antitoxin) = the treatment that neutralizes the toxin of the diphtheria bacterium; how quickly it is given can mean the difference between life and death. inmunidad de rebaño (herd immunity) = the state in which, because most people are immune, even the unvaccinated are indirectly protected.
There is a vaccine, and there is a cure. That people still die is not a problem of the disease, but of the system.
References
※ This article is the author’s commentary based on public information. Please confirm the latest figures, dates and procedures with governments and primary sources. Quotations are kept minimal and sources are cited.