Pertussis Burden Rebounded After Pandemic Disruptions, With Infants Bearing the Highest Mortality Risk
Despite decades of routine childhood immunization, pertussis remains a persistent cause of vaccine-preventable illness and death, especially in the first months of life. A Global Burden of Disease analysis spanning 204 countries and territories from 1990 through 2023 shows a long-term decline in both incidence and mortality, but the pandemic era interrupted that trajectory and was followed by a striking rebound in cases and deaths.
The global pattern was not uniform. Age-standardized mortality fell by 61.2% over the full study period, while age-standardized incidence declined by 41.6%. Those gains, however, did not hold steady through the pandemic years. Between 2020 and 2023, incidence rose by 102.6% and mortality by 66.1% relative to the unusually low estimates seen during the pandemic period. In 2023 alone, the model estimated 18.9 million cases and 115,000 deaths attributable to pertussis.
The burden remains concentrated where health systems have the least room to miss a vaccine dose.
Infant Vulnerability Drives the Deadliest Part of the Epidemic
The age pattern is clinically familiar and biologically unforgiving. Infants younger than 6 months carried the highest population-adjusted risk, a period when protection depends heavily on timely primary immunization, maternal antibodies, and rapid recognition of disease. In this age group, even short delays in vaccination can leave a narrow but dangerous window for severe cough illness, apnea, pneumonia, and death.
That vulnerability explains why pertussis mortality remains so high even as global averages improve. Older children and adults can still transmit infection, often with milder or atypical symptoms, but the steepest clinical consequences fall on the youngest infants. Once transmission reaches households, maternity wards, or communities with delayed vaccine uptake, the cascade can be rapid and severe.
The modeled geography of death is equally stark. Sub-Saharan Africa accounted for roughly 65% of global pertussis deaths in 2023. This concentration reflects more than pathogen biology; it tracks with the structural realities of vaccine access, surveillance capacity, case detection, and treatment availability. Where routine immunization is delayed or incomplete, pertussis retains the ability to move from nuisance infection to lethal pediatric disease.
Short-Term Pandemic Gains Gave Way to a Rapid Rebound
The pandemic years created an unusual epidemiologic interruption. Reduced travel, altered health-seeking behavior, school closures, masking, and broader changes in respiratory virus circulation likely suppressed pertussis transmission and made some estimates appear artificially low. Once those constraints eased, incidence and mortality climbed back sharply.
The post-pandemic rebound matters because pertussis is not a disease that simply disappears when surveillance weakens. It reemerges when immunity gaps widen, when routine infant vaccination slips, and when population mixing resumes. The 102.6% increase in incidence from 2020 to 2023 signals more than a statistical correction; it reflects renewed circulation in settings where protection was interrupted or incomplete.
Mortality followed the same direction, though with greater uncertainty. The 66.1% increase in deaths between 2020 and 2023 was estimated with a wide uncertainty interval, ranging from 2.4% to 174.5%. Even with that spread, the direction of travel is clinically concerning. A disease long considered preventable is still killing large numbers of children, and the burden rose again once the pandemic-era trough passed.
Why Coverage Gaps Still Matter in a Vaccine-Preventable Infection
Pertussis control depends on layered prevention. Infant series timing, maternal immunization where recommended and feasible, post-exposure awareness, and surveillance all contribute to protection. Miss one layer, and the youngest patients remain exposed.
The biology of the disease makes that especially important. Bordetella pertussis spreads efficiently through respiratory droplets and can circulate before diagnosis is obvious. Early symptoms often resemble a common viral infection, which delays testing and treatment. In infants, the presentation may be less classic cough and more apnea, cyanosis, feeding difficulty, or abrupt deterioration. Those features make timely prevention more valuable than reactive care.
The modeled inverse relationship with the sociodemographic index reinforces the same point from another angle. Lower-resource settings continue to carry the heaviest load, and the disease burden rises as access to vaccination and surveillance falls. The result is an avoidable global inequality: pertussis is increasingly preventable in settings with robust health systems, yet it remains dangerous where systems are fragile.
Surveillance and Maternal Protection Remain Central Targets
The analysis supports a straightforward clinical and public health response: strengthen timely infant vaccination, expand maternal immunization where recommended and feasible, and improve surveillance in regions with the highest susceptibility. Those steps are not abstract policy slogans. They are the practical tools that determine whether an infant encounters pertussis with passive protection or with none at all.
Maternal vaccination matters because it can bridge the interval before an infant is old enough to mount protection from the primary series. Surveillance matters because pertussis is often underrecognized, especially where diagnostic testing is limited or cough syndromes are attributed to other respiratory infections. Without reliable case detection, rising transmission can remain hidden until deaths accumulate.
The high mortality concentration in sub-Saharan Africa also argues for geographic prioritization rather than evenly distributed intervention. Where risk is greatest, small failures in immunization coverage can produce disproportionate harm. In that setting, each missed dose carries more weight than a national average might suggest.
Modeling Strengths Leave Open Practical Questions
As a Global Burden of Disease analysis, the study offers a broad and consistent estimate of pertussis trends across nearly every country and territory, but modeled estimates are still shaped by the quality of underlying data. Underdiagnosis, inconsistent reporting, and uncertainty around cause attribution can all influence the final estimates, particularly in regions with limited laboratory confirmation.
Even so, the central message is difficult to ignore. Pertussis has declined over the long term, yet it has not been pushed out of global circulation. Pandemic-era disruption exposed how quickly gains can erode when vaccine delivery, surveillance, and routine care are interrupted.
The most consequential question for clinicians and public health leaders is whether current immunization systems can close the remaining gaps before the next rebound arrives. In infants younger than 6 months, the margin for delay is small, and the clinical cost of missed protection remains unacceptably high.