Old Disease and New Challenges: Major Obstacles of Current Strategies in the Prevention of Pertussis

Childhood pertussis is still here: An Asian city's perspectives

INTRODUCTION

Pertussis, or whooping cough, is a highly contagious respiratory infection that is caused by the bacterium Bordetella pertussis. It is one of the most common causes of death in childhood. It is also a frequent cause of chronic cough in children, adolescents, and adults.

METHODS

Global and Hong Kong perspectives of childhood pertussis were described.

RESULTS

Hong Kong has prided herself in the city's childhood immunization program. There appear to be no major outbreaks of pertussis since the 1960s. Nevertheless, pediatricians may see isolated cases of pertussis or pertussis-like cases from time to time. Occasionally, infants are severely affected with apneas and managed with ventilator supports in the PICU. Outbreaks of the notifiable disease continue to occur despite a reasonable surveillance system and vaccination program in Hong Kong. Vaccination of mothers, adolescents, and adults are efficacious methods to further reduce the risks of pertussis. Macrolides remain efficacious antibiotics especially used early during the infectious phase. Infants with pertussis may require intensive care support and morbidity is high.

CONCLUSIONS

Physicians should be reminded from time to time that outbreaks of pertussis still exist in Hong Kong and in many cities globally.

Seroprevalence of Bordetella pertussis among a nationally representative sample of Iranian pediatric population: The childhood and adolescence surveillance and prevention of adult noncommunicable disease-V study

Background:

Pertussis is a vaccine-preventable respiratory infection and seroepidemiology of the infection could be a marker of the pertussis immunity in a population. In many countries, despite vaccination coverage, high prevalence of pertussis has been observed. The present study aimed to evaluate the immunoglobulin G (IgG) antibody against pertussis and the role of demographic and anthropometric variables on the immunity rate in the Iranian pediatric population to evaluate the impact of existing immunization program in order to envisage future vaccination strategies to prevent infection.

Methods:

In a cross-sectional multi-centric study, 1593 samples of the students aged 7–18 years, who had been enrolled in a national survey (Childhood and Adolescence Surveillance and Prevention of Adult Noncommunicable disease-V), were randomly selected and tested for IgG antibody against Bordetella pertussis (BP) by enzyme-linked immunosorbent assay. The age, gender, education, residency, geographical region, and body mass index (BMI) were extracted from the questionnaires of the COSPIAN-Survey. Multiple logistic regression models were used to assess the associations between the variables with the IgG antibody against BP. Data were presented by odds ratio (OR), 95% confidence interval (95% CI) and P values (P): (OR [95% CI]; P).

Results:

Subjects were consisted of 774 boys and 750 girls, with a mean (standard deviation) age of 12.39 (3.03) years. Overall, BP seroprevalence was 59.8%. There were higher BMI values in seronegative ones versus seropositive (18.62 ± 4.07 vs. 18.15 ± 3.94, P = 0.041, 95% CI = 0.23 [0.02–0.92]). However, the categorized BMI for age was not significantly associated with IgG levels (0.27 [0.25–0.29]; 0.27). BP seroprevalence was not significantly different between geographical regions (0.06 [0.05–0.07]; 0.06), genders (1.17 [0.93–1.47]; 0.18), area of residence (1.07 [0.82–1.4]; 0.61), and educational levels (0.94 [0.75–1.19]; 0.62).

Conclusion:

IgG antibody against pertussis was not detected in nearly 40% of the subjects who had history of vaccination against pertussis. It is recommended to monitor the incidence of pertussis in high-risk populations closely and administer a booster dose of acellular pertussis vaccine in adolescents.

Transversal sero-epidemiological study of Bordetella pertussis in Tehran, Iran

Objectives

Pertussis remains endemic despite high vaccine coverage in infants and toddlers. Pertussis vaccines confer protection but immunity wanes overtime and boosters are needed in a lifetime. Iran, eligible for the Expanded Program on Immunization that includes the primary immunization, implemented two additional booster doses using a whole-cell vaccine (wPV) at 18 months-old and about 6 years-old. Duration of protection induced by the wPVs currently in use and their impact as pre-school booster are not well documented. This study aimed at assessing vaccination compliance and at estimating the duration of protection conferred by vaccination with wPV in children aged < 15 years in Tehran, Iran.

Methods

Detailed information on vaccination history and capillary blood samples were obtained from 1047 children aged 3–15 years who completed the 3 doses-primary pertussis immunization, in Tehran. Anti-pertussis toxin IgG levels were quantified by ELISA.

Results

Compliance was very high with 93.3% of children who received the three primary and 1^st booster doses in a timely manner. Timeliness of the 2^nd booster was lower (63.3%). Rate of seropositive samples continuously and significantly increased from 1–2 to 5–6 years after 1^st booster attaining 30.4% of children exhibiting serological sign of recent contact with B. pertussis. Second booster dating back 1 or 2 years was associated with high antibody titers, which significantly decreased within 3 years from injection. Among children who received 2^nd booster injection more than 2 years before serum analysis, seroprevalence of pertussis infection was 8.4% and seropositivity rate was higher from the 10 years-old group.

Conclusion

Seropositivity in children aged 6–7 years with no 2^nd booster supports the need for a vaccination at that age. Adolescent booster may also be considered.

Spatio-temporal analysis of Pertussis using geographic information system among Iranian population during 2012-2018

Background: In spite of existing vaccination programs in many countries, outbreaks of pertussis are still reported. In Iran, the suspected and confirmed cases of pertussis are reported annually. Due to the lack of similar studies, the purpose of the current study was to determine the Spatio-temporal distribution of Pertussis using Geographic Information System (GIS) to identify high-risk areas in Iran during 2012-2018.

Methods: In the current cross-sectional study, registered data in the department of vaccine-preventable diseases in the Iranian ministry of health were used. To assess the temporal trend, the Cochran–Armitage test was used. To show the spatial distribution and to identify hotspot areas, Choropleth map and Getis-Ord Gi statistics were used. All analyses performed by Arc.map10.5, Stata 15 and Excel 2010.

Results: The incidence of suspect pertussis cases had an increasing trend but did not have a linear trend (p=0.06). Most of the cases happened in under 1 year infants (62.66%). The incidence of reported cases in northern areas was higher than in the Southern areas. The Zanjan had the most reported cases during the understudied period with a median of 7.63 reported cases per 100,000. The clustering of infection and hotspots were identified in northern areas of Iran including Qazvin, Qom, Markazi, and Hamadan.

Conclusion: Our results showed that the cumulative incidence of reported cases is increasing. The northern provinces had the highest incidence of Pertussis. Therefore, the causes of this spatio-temporal pattern of pertussis should be determined. Also, supervision on vaccination programs in high-risk areas is recommended.