Pertussis is a highly contagious bacterial disease of the respiratory tract that can be prevented by vaccination. Before the COVID-19 pandemic, the vaccine coverage rate for the third dose of a DPT-containing vaccine was 86%, with large disparities among countries. Since 2022, many high-income countries have reported a resurgence of pertussis, especially in the European region, but the disease has also caused outbreaks in middle- and low-income countries, despite their less extensive disease surveillance capacities. This paper aims to review the incidence rates (IRs) of pertussis in high-, middle-, and low-income countries following the COVID-19 pandemic and to discuss the most relevant factors associated with the resurgence of the disease. The epidemiology of pertussis is highly variable and is influenced not only by the type of vaccine used but also by the specific characteristics of the disease, vaccine coverage rates, vaccination schedules, and the quality of surveillance. Since the cessation of COVID-19 measures, there have been significant pertussis outbreaks that could have been partially mitigated with higher coverage rates and more comprehensive pertussis vaccination throughout life.

Infant vaccination against the hepatitis B virus began in the World Health Organization South East Asia Region and the Western Pacific Region between 1983 and 2016. This systematic review examined the seroprevalence of hepatitis B surface antigen (HBsAg) in children and the rate of mother-to-child transmission (MTCT) in these regions between 1990 and 2020. MEDLINE and EMBASE were searched for articles published between January 1990 and September 2020, which reported seroprevalence of HBsAg in children aged 0-15 years and/or the rate of MTCT in the South East Asia Region and Western Pacific Region. A pragmatic review identified supporting information. This review was registered in the International Prospective Register of Systematic Reviews (#CRD42020211707). Of 115 included studies, 77 (24 countries) reported HBsAg prevalence, and 38 (nine countries) reported MTCT. The seroprevalence of HBsAg ranged between 0.0% and 27.4%, with a decreasing trend over time in each country. MTCT rates were 0.0-5.2% in infants of mothers who are hepatitis B e antigen-negative and 2.7-53.0% in infants of mothers who are hepatitis B e antigen-positive. After the introduction of infant hepatitis B virus vaccination programs, the countries in South East Asia Region and Western Pacific Region observed a reduction in HBsAg seroprevalence in children. Nevertheless, the risk of MTCT persists, emphasizing the importance of antenatal screening to identify high-risk pregnancies.

The national immunization program in Mexico includes a 3-dose primary series of pertussis vaccine and a toddler booster dose. In Mexico, whole-cell pertussis vaccines (wP) were switched in 2007 to acellular pertussis vaccines (aP). This retrospective study using Mexican National Databases of Health and population surveillance (2000-2019) assessed the incidence of pertussis, infant pertussis vaccination coverage, and vaccine effectiveness (VE) against clinically-diagnosed and/or laboratory-confirmed pertussis in children aged 6.5-18.5 or 24.5 months for the primary series, and children aged 18.5 or 24.5-48.5 months for the toddler booster. The incidence of pertussis sharply increased in 2012 and was highest in 2012, 2015, and 2016 (0.84-0.94/100,000 person-years). Coverage was highest for the first dose in the primary series, decreasing for each subsequent dose. The VE against notified pertussis was 96.4% (95% CI: 94.7, 97.6) for the first three doses of wP vaccine (2000-2007) and 95.7% (95% CI: 95.1, 96.2) for the first three doses of aP vaccine (2008-2019). Our findings suggested high levels of vaccine effectiveness overall were achieved for the aP and wP vaccines in Mexico between 2000 and 2019.

Vaccine-related errors (VREs) result from mistakes in vaccine preparation, handling, storage, or administration. We aimed to assess physicians’ and nurses’ experiences of VREs in South Korea, focusing on reconstitution issues, and to understand the barriers to and facilitators of preventing them. This was a cross-sectional study using an internet-based survey to examine experiences of reconstitution-related errors, and experience or preference with regard to ready-to-use vaccines (RTU) by physicians and nurses. A total of 700 participants, including 250 physicians and 450 nurses, responded to the questionnaire. In total, 76.4% and 41.5% of the physicians and nurses, respectively, reported an error related to reconstituted vaccines. All errors had been reported as experienced by between 4.9% and 52.0% of physicians or nurses. The errors were reported to occur in more than one in 100 vaccinations for inadequate shaking of vaccines by 28.0% of physicians and 6.9% of nurses, incomplete aspiration of reconstitution vials by 28.0% of physicians and 6.4% of nurses, and spillage or leakage during reconstitution by 20.8% of physicians and 6.9% of nurses. A total of 94.8% of physicians had experience with RTU vaccines, and all preferred RTU formulations. In conclusion, this study highlights the high frequency and types of reconstitution-related errors in South Korea. RTU vaccines could help reduce the time needed for preparation and reduce the risk of errors in South Korea.

In recent years, outbreaks and a rising incidence of diphtheria, tetanus, and pertussis have occurred in Asia, particularly in older children. A systematic search of MEDLINE and Embase was conducted from January 2000 to October 2020 to identify the epidemiology of diphtheria, tetanus, pertussis, and poliomyelitis in children and adolescents (aged 3-18 years) in Asia. The results were then related to vaccination schedules, booster coverage rates, pertussis source of infection, and booster immunogenicity, as identified by a pragmatic review. The International Prospective Register of Systematic Reviews (PROSPERO) registration: #CRD42020222445. A total of 35 studies were included in this review. Limited data were reported on the epidemiology of diphtheria, tetanus, pertussis, and poliomyelitis. Data from studies reporting the incidence of diphtheria and pertussis exemplify the shift in epidemiology to older children/adolescents. Seroprevalence data suggest that immunity to pertussis and diphtheria is below the level of herd immunity in several Asian countries in this population. The true burden of diphtheria, pertussis, and tetanus in children aged 3-18 years in Asia is unknown because of weak or absent nationwide surveillance systems. The available evidence highlights the inadequacies in immunity, either by gaps in a recommendation or suboptimal booster coverage, supporting the public health need for booster vaccinations in this population.

The Global Polio Eradication Initiative (GPEI), launched in 1988, has successfully reduced wild poliovirus (WPV) cases by over 99.9%, with WPV type 2 and WPV3 declared eradicated in 2015 and 2019, respectively. However, as of 2024, WPV1 remains endemic in Afghanistan and Pakistan. Since 2000, outbreaks of circulating virus derived of polio vaccines (cVDPVs) have emerged in multiple regions, primary driven by low vaccine coverage rates (VCRs). The COVID-19 pandemic disrupted routine immunization, resulting in millions of unvaccinated children, and leaving many countries vulnerable to both WPV1 and cVDPVs outbreaks. This paper reviews the epidemiological landscape of poliomyelitis post the COVID-19 pandemic, and the strategies and challenges to achieve the global polio eradication.