Abstract

Background Bordetella pertussis is a human pathogen which causes pertussis, or whooping cough. The diphtheria-tetanus-pertussis immunization has significantly reduced the morbidity and mortality of pertussis globally. However, higher prevalence and resurgence of pertussis cases among both vaccinated and unvaccinated people has raised questions on the effectiveness of pertussis vaccine over time. Therefore, the objective of this study was to assess the protective effectiveness of pertussis vaccine in the Amhara Regional State, Ethiopia. Methods A nested matched case-control study design approach was used with vaccinated individuals as cases and unvaccinated individuals as controls. The study was conducted from July 2018 to February 2019. Real-time (RT-) PCR assay was done to ascertain the presence of pertussis among clinically suspected patients. Bivariable and multivariable logistic regression analyses were computed to estimate the crude and adjusted odds ratios (ORs), respectively. Vaccine effectiveness was calculated as (1 − OR) × 100. Adjusted OR with 95% CI and a P value <0.05 were used to assess statistical significance. Results A total of 112 vaccinated and 223 unvaccinated controls were enrolled for the study. Of the total participants, 173/335 (51.6%) were males. The prevalence of pertussis among vaccinated was 35/112 (31.3%), whereas it was 84/223 (37.7%) among the control group. The adjusted matched vaccine protective effectiveness against B. pertussis infection following three doses of whole-cell vaccine was 25% among children aged between 6 and 9 years. Adjusted estimates of vaccine protective effectiveness for participants who had complete vaccination, stratified by time since last vaccination, were 50% at 6 years, 34% at 7 years, and 2% at 8–9 years since last vaccination. Conclusion Despite the availability and good coverage of childhood vaccination, the effectiveness of pertussis vaccine was found to be low in the Amhara region, Ethiopia. Moreover, we observed declining trends in the protective effectiveness of the vaccine after 6 years of vaccination. Thus, by considering the waning nature of immune response which is induced by whole-cell vaccine during early life, booster dose is highly recommended to optimize pertussis prevention and control strategies.

Highlights

  • Pertussis, or whooping cough, is a highly contagious respiratory tract infection which has been poorly controlled compared with other vaccine-preventable diseases [1, 2]

  • Mass vaccination programs for childhood diseases have been highly successful in reducing the incidence and public health impact of the targeted diseases. e whole-cell pertussis vaccine introduced in the 1940s was replaced by the less reactogenic acellular vaccines in the1980s. e diphtheria-tetanus-pertussis (DTP) immunization has International Journal of Microbiology significantly reduced the morbidity and mortality of pertussis globally. us, DTP vaccination has made a substantial impact on the pertussis epidemiology

  • There are no studies assessing the protective effectiveness of pertussis vaccine in the study area and Ethiopia at large. erefore, the aim of the present study was to determine the protective effectiveness of pertussis vaccine in the Amhara Regional State, Ethiopia

Read more

Summary

Introduction

Whooping cough, is a highly contagious respiratory tract infection which has been poorly controlled compared with other vaccine-preventable diseases [1, 2]. Higher prevalence and resurgence of pertussis cases among both vaccinated and unvaccinated people has raised questions on the effectiveness of pertussis vaccine over time. Erefore, the objective of this study was to assess the protective effectiveness of pertussis vaccine in the Amhara Regional State, Ethiopia. E adjusted matched vaccine protective effectiveness against B. pertussis infection following three doses of wholecell vaccine was 25% among children aged between 6 and 9 years. Adjusted estimates of vaccine protective effectiveness for participants who had complete vaccination, stratified by time since last vaccination, were 50% at 6 years, 34% at 7 years, and 2% at 8–9 years since last vaccination. Us, by considering the waning nature of immune response which is induced by whole-cell vaccine during early life, booster dose is highly recommended to optimize pertussis prevention and control strategies We observed declining trends in the protective effectiveness of the vaccine after 6 years of vaccination. us, by considering the waning nature of immune response which is induced by whole-cell vaccine during early life, booster dose is highly recommended to optimize pertussis prevention and control strategies

Objectives
Methods
Results
Discussion
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call