Pertussis Prevalence and Its Determinants among Children with Persistent Cough in Urban Uganda
April
Pertussis Prevalence and Its Determinants among Children with Persistent Cough in Urban Uganda
Vincent Kayina 0 1 2 3
Samuel Kyobe 0 1 2 3
Fred A. Katabazi 0 1 2 3
Edgar Kigozi 0 1 2 3
Moses Okee 0 1 2 3
Beatrice Odongkara 0 1 2 3
Harriet M. Babikako 0 1 2 3
Christopher C. Whalen 0 1 2 3
Moses L. Joloba 0 1 2 3
Philippa M. Musoke 0 1 2 3
Ezekiel Mupere 0 1 2 3
0 Competing Interests: The authors have declared that no competing interests exist
1 Funding: This work was supported by Training Health Researchers into Vocational Excellence in East Africa (THRiVE), grant number 087540 funded by the Wellcome Trust. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the supporting offices
2 Academic Editor: Daniela Flavia Hozbor, Universidad Nacional de La Plata., ARGENTINA
3 1 Department of Paediatrics & Child Health, College of Health Sciences, Makerere University , Kampala , Uganda , 2 Department of Medical Microbiology, College of Health Sciences, Makerere University , Kampala , Uganda , 3 Department of Paediatrics, School of Medicine, Gulu University , Gulu , Uganda , 4 Child Health and Development Center, College of Health Sciences, Makerere University , Kampala , Uganda , 5 Department of Epidemiology & Biostatistics, College of Public Health, University of Georgia , Athens , United States of America
We determined prevalence of pertussis infection and its associated host and environmental factors to generate information that would guide strategies for disease control. In a cross-sectional study, 449 children aged 3 months to 12 years with persistent cough lasting 14 days were enrolled and evaluated for pertussis using DNA polymerase chain reaction (PCR) and ELISA serology tests. Pertussis prevalence was 67 (15% (95% Confidence Interval (CI): 12-18)) and 81 (20% (95% CI: 16-24)) by PCR and ELISA, respectively among 449 participating children. The prevalence was highest in children with >59 months of age despite high vaccination coverage of 94% in this age group. Study demographic and clinical characteristics were similar between pertussis and non-pertussis cases. Of the 449 children, 133 (30%) had a coughing household member and 316 (70%) did not. Among 133 children that had a coughing household member, sex of child, sharing bed with a coughing household member and having a coughing individual in the neighborhood were factors associated with pertussis. Children that had shared a bed with a coughing household individual had seven-fold likelihood of having pertussis compared to children that did not (odds ratio (OR) 7.16 (95% CI: 1.2441.44)). Among the 316 children that did not have a coughing household member, age <23 months, having or contact with a coughing individual in neighborhood, a residence with one room, and having a caretaker with >40 years of age were the factors associated with pertussis. Age <23months was three times more likely to be associated with pertussis compared to age 24-59 months (OR 2.97 (95% CI: 1.07-8.28)).
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Findings suggest high prevalence of pertussis among children with persistent cough at a
health facility and it was marked in children >59 months of age, suggesting the possibility of
waning immunity. The factors associated with pertussis varied by presence or absence of a
coughing household member.
The control of pertussis or whooping cough is of public health concern worldwide, because it is
estimated that over 10 million cases and as many as 400,000 pertussis-related deaths occur
annually, with 90% of the burden in infants from developing countries [1,2,3]. However, the
optimum strategies to improve control of pertussis remain uncertain as robust data for disease
incidence and surveillance are sparse particularly in developing countries [2]. Pertussis affects
all age groups and can occur in previously immunized or infected individuals [4,5]. The
introduction of mass vaccination of children in the mid-20th century decreased the incidence of
pertussis significantly; however, pertussis has remained endemic because available vaccines
prevent disease but to a lesser extent infection and transmission [1,6,7]. The infection
continues to kill young children and even in countries with strong vaccination programs clinicians
miss the diagnosis [1,3]. Over the last two decades there has been a resurgence of pertussis
disease in well-vaccinated populations worldwide, largely due to rapid loss of protective immunity
and pathogen adaptation [6,7]. The resurgence has been accompanied by a shift to older age
groups, raising concerns about household transmission to vulnerable infants and the need for
reinforcement of vaccination strategies.
In Uganda, pertussis vaccination was introduced in 1974 by the National Expanded
Program in Immunization (UNEPI). The UNEPI provides three doses of whole cell pertussis
vaccine at 6, 10, and 14 weeks of age in combination with diphtheria, tetanus, hepatitis B and
hemophilus influenza type b (...truncated)