As of mid-May 2025, Pan American Health Organization (PAHO) sounded the alarm: pertussis is roaring back across the Americas, with 14,201 confirmed cases and 93 deaths in just five months. The outbreak spans seven countries—Brazil, Colombia, Ecuador, United States, Mexico, Paraguay, and Peru—and the numbers are climbing faster than anyone expected. This isn’t just a spike. It’s a warning sign. And the root cause? A quiet, dangerous collapse in childhood vaccination rates.
Why This Outbreak Is Different
Back in 2023, the Americas saw just 4,139 pertussis cases. Last year, that jumped to over 43,000. And now, in only five months of 2025, we’re already past the total from two years ago. The twist? It’s not that the bacteria got stronger. It’s that fewer kids are protected.
PAHO’s data shows something alarming: in five of the seven countries reporting outbreaks, fewer than 95% of infants received all three doses of the diphtheria-tetanus-pertussis (DTP3) vaccine in 2024. That’s the global gold standard. Anything below it creates gaps—gaps where babies, too young to be fully vaccinated, get exposed. In 2021, during the pandemic’s peak, DTP1 coverage dropped to 87%, and DTP3 to just 81%. Even in 2023, recovery was shaky: only 90% and 88% respectively. We’re still missing the target. And it’s costing lives.
Who’s Most at Risk—and Why
Infants under six months bear the brunt. Their immune systems can’t fight off Bordetella pertussis effectively. Whooping cough isn’t just a bad cough. It can trigger respiratory arrest, pneumonia, seizures, even brain damage. Nine of the 93 deaths reported this year were in babies under three months old. That’s the heartbreaking reality.
“We’re seeing the same pattern we saw in the early 2000s,” said Dr. Pilar Ramón-Pardo, head of PAHO’s Special Program on Antimicrobial Resistance, in a statement released August 26, 2025. “When vaccination coverage slips, the disease doesn’t wait. It finds the unvaccinated. And it hits hardest where the safety net is thinnest.”
Subnational disparities make it worse. In rural Peru, for instance, DTP3 coverage in some provinces hovers near 60%. In urban Mexico City, it’s over 92%. That kind of gap turns neighborhoods into hotspots. And because pertussis spreads through coughs and sneezes, one unvaccinated child can trigger a chain reaction.
What PAHO Is Asking Countries to Do
PAHO’s June 4, 2025, alert isn’t just a heads-up—it’s a blueprint. And it’s specific.
- Hit 95% coverage for DTP1 and DTP3 in infants under one year—no exceptions.
- Administer booster doses at ages 1–6, ideally during the second year of life.
- Vaccinate pregnant women with Tdap (tetanus, diphtheria, acellular pertussis) between 27 and 36 weeks of gestation—this passes protective antibodies to newborns.
- Immunize all healthcare workers who handle newborns.
- Strengthen surveillance systems to detect outbreaks within days, not weeks.
These aren’t new ideas. PAHO’s Technical Advisory Group has been pushing this exact plan since 2012—and again in 2017. Back then, they recommended using whole-cell pertussis vaccines for infants, which offer longer-lasting immunity than the acellular versions now common in wealthier countries. But many nations switched to acellular vaccines due to perceived side effects, even though they’re less durable. Now, we’re paying the price.
The Bigger Picture: A Global Pattern
This isn’t just an Americas problem. Japan’s Infectious Diseases Weekly Report noted a sharp uptick in cases through May 2025, prompting their Expert Council on Vaccination to urge parents to use the 5-in-1 vaccine (DPT-IPV-Hib) starting at two months. The same trend is visible in parts of Europe and Australia.
The University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP) added another layer: antibiotic-resistant strains of pertussis are emerging. When kids get sick and doctors prescribe antibiotics unnecessarily—often because they can’t quickly confirm the diagnosis—it fuels resistance. That makes outbreaks harder to control.
“We’re not just losing herd immunity,” said CIDRAP epidemiologist Dr. Lisa Chen in an interview. “We’re creating a perfect storm: lower vaccination, delayed diagnosis, and overuse of antibiotics. It’s a triple threat.”
What Happens Next?
PAHO is pushing for immediate action. Countries are expected to report updated vaccination coverage data by October 2025. Some, like Colombia and Mexico, have already launched mobile vaccination units in underserved neighborhoods. Others, including Paraguay, are working with community health workers to track unvaccinated infants.
But time is running out. The next surge could come this fall, as children return to school and families gather indoors. If coverage doesn’t climb above 95% by the end of the year, experts fear a repeat of the 2010 California outbreak—where 10 infants died and over 9,000 cases were recorded.
Here’s the thing: we’ve solved this before. In the 1990s, pertussis was nearly eliminated in the Americas. It took coordinated vaccination campaigns, strong public trust, and political will. We have the tools. We just need to use them.
Frequently Asked Questions
Why is the DTP3 vaccine so important for babies under one year?
The third dose of DTP vaccine, given between 6 and 12 months, completes the primary series that gives infants strong, lasting protection against whooping cough. Without it, babies remain vulnerable to severe complications like pneumonia or brain damage. Studies show infants who miss DTP3 are 14 times more likely to be hospitalized with pertussis than those fully vaccinated.
Can pregnant women really protect their newborns by getting the Tdap shot?
Yes. When a pregnant woman receives Tdap between 27 and 36 weeks, her body produces antibodies that cross the placenta and protect the baby during the first vulnerable months. CDC data shows this reduces infant pertussis cases by 78% and hospitalizations by 90%. It’s one of the most effective ways to shield newborns who are too young to be vaccinated themselves.
Why are some countries still using whole-cell pertussis vaccines?
Whole-cell vaccines, though more likely to cause mild fever or swelling, provide broader and longer-lasting immunity than acellular versions. Countries like Brazil and China still use them in their infant schedules because they’re more effective at preventing transmission. PAHO recommends them for primary series where resources allow, especially in outbreak settings.
How do I know if my child’s vaccination record is up to date?
Children need five pertussis-containing doses: three primary doses at 6, 10, and 14 weeks, a booster at 12–23 months, and another between 4 and 7 years. A final adolescent booster (Tdap) is recommended at 11–15 years. Check with your clinic or public health portal—many now offer digital records. If you’re unsure, a blood test can check for antibodies, but vaccination is safer than waiting.
Is there a risk of antibiotic resistance from treating pertussis?
Yes. While antibiotics like azithromycin can reduce transmission if given early, overuse drives resistance. In the U.S. and parts of Latin America, strains resistant to macrolide antibiotics are rising. PAHO urges testing before prescribing—especially since many coughs are viral. Misuse doesn’t help the patient and harms the community.
What’s being done to reach unvaccinated communities?
In Ecuador and Peru, mobile clinics now visit remote villages and informal settlements. In Mexico, community health workers are using WhatsApp to remind parents of due dates. In the United States, state health departments are partnering with churches and schools to host pop-up clinics. Trust-building, not just supply, is the new priority.