As of July 2025, pertussis outbreaks have been observed in at least 42 countries across the globe (Fig. 1, Table 1; list not exhaustive) [41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96]. Nonetheless, comprehensive tracking of these outbreaks is challenging due to heterogeneity in surveillance systems, the dynamic nature of the outbreaks and the reporting of the data, which is not always done in real-time nor publicly available. Moreover, the heterogeneity of surveillance capacities across countries sometimes leads to cases of older children, adolescents, and adults remaining undocumented, particularly in low-income countries without robust surveillance systems. While seroprevalence studies estimate wide circulation of B. pertussis, the aforementioned factors limit the scope of comparison of the number of cases reported across countries [97, 98].

Countries using aP and wP vaccines in the children schedule. aP acellular pertussis, wP whole-cell pertussis

Among the 42 countries identified, 30 recommend aP vaccines in their pediatric immunization schedule, while 12 countries recommend wP vaccines [51, 59, 89, 90, 99,100,101,102,103,104,105]. Notably, 9 of 12 countries using wP vaccines have a three-dose diphtheria, tetanus, and pertussis (DTP3) VCR lower than the WHO-recommended 90% rate [106]. The exceptions are Brazil, Colombia, and Thailand [83, 104, 106]. In these wP vaccine-using countries, reported cases were limited to infants and children [53, 57, 73, 75, 76, 85, 100, 107,108,109,110].

Most aP-using countries experiencing recent pertussis outbreaks have high VCR for the DTP series, with a few exceptions, such as Mexico, New Zealand (close to 90%), Slovenia (close to 90%), and South Africa, where the DTP3 VCR was lower than 90% in 2023. Economic disparities have resulted in aP vaccine-using countries being typically equipped with more extensive surveillance capacity than most wP vaccine-using countries. This enhanced capacity may allow for broader characterization of case distribution, primarily facilitating improved detection in very young infants and older adults who are further removed from their most recent vaccine dose [58, 65,66,67,68,69, 72, 86,87,88]. Thus, the availability of robust surveillance systems could contribute to a perception that more pertussis cases are observed in aP vaccine-using countries. In some countries, such as Spain, Czechia, Croatia, and Denmark, the number of cases is highest among adolescents and adults [43,44,45, 72].

Based on vaccination data, the countries with recent outbreaks could be categorized into four groups: countries with low DTP3 VCR, countries with no recommendations for vaccination during pregnancy, countries having no recommendations for adolescent and adult boosters, and countries with high vaccine uptake and extensive vaccination schedules.

This article is based on previously conducted studies or disease surveillance activities and does not contain any new studies with human participants or animals performed by any of the authors.

Pertussis has a very high reproductive number in unvaccinated populations. Although the available vaccines are highly efficacious, they are not 100% effective and do not confer lifelong protection. Therefore, very high VCR is essential for effective disease control. The WHO recommends that all children receive at least 3 doses of the pertussis vaccine, with a VCR of 90% or higher for all countries. However, despite this recommendation and ongoing efforts, many countries are yet to achieve the optimal VCR owing to multiple factors documented in literature—such as limited access to healthcare services, vaccine hesitancy, logistical challenges in vaccine delivery, and lack of awareness among target populations [2, 106, 111,112,113].

COVID-19 lockdowns disrupted immunization services and outreach programs, impacting childhood vaccination rates globally. According to WHO data, 15 countries showed suboptimal DTP3 VCRs in 2023, including nine countries using wP vaccines and six using aP vaccines (Fig. 2) [99, 106]. Low DTP3 uptake rates can result in cohorts of unvaccinated children in community cares, schools, and kindergartens, thus compromising herd immunity and increasing the risk of transmission to children who are partially vaccinated or too young to be immunized [114, 115]. Consequently, infants and children are primarily affected in countries with low uptake rates (Table 1). In South Africa, between January 2022 and January 2023, a total of 818 cases of pertussis were detected, with over 95% of these cases occurring between July 2022 and January 2023. The majority (58.0%) of cases reported were in children aged < 5 years of age, of which 78% were under 3 months of age. Mortality was also notably high among children during January 2022–January 2023, with 12 of 14 deaths occurring in children under the age of 5 years. In South Africa, the DTP3 VCR was 79% in 2023 [49,50,51,52].

Countries with suboptimal DTP3 coverage in 2023 considering the vaccine type. *WHO/UNICEF Estimates of National Immunization Coverage (WUENIC). aP acellular pertussis, DTP3 three-dose primary series with diphtheria, tetanus, and pertussis vaccines, UNICEF United Nations Children’s Fund, VCR vaccination coverage rate, WHO World Health Organization, wP whole-cell pertussis

Similar trends emerged across Bolivia, the Central African Republic, Ethiopia, Ecuador, Peru, and Mexico [53, 89, 90,