Table 2

Incidence and Transmission Dynamics of Bordetella pertussis Infection in Rural and Urban Communities, South Africa, 2016‒2018

Fahima Moosa

, Stefano Tempia, Jackie Kleynhans, Meredith McMorrow, Jocelyn Moyes, Mignon du Plessis, Maimuna Carrim, Florette K. Treurnicht, Orienka Helferscee, Thulisa Mkhencele, Azwifarwi Mathunjwa, Neil A. Martinson, Kathleen Kahn, Limakatso Lebina, Floidy Wafawanaka, Cheryl Cohen, Anne von Gottberg, Nicole Wolter, and for the PHIRST Group

Author affiliations: University of the Witwatersrand, Johannesburg, South Africa (F. Moosa, S. Tempia, J. Moyes, M. du Plessis, M. Carrim, O. Hellferscee, C. Cohen, A. von Gottberg, N. Wolter); National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg (F. Moosa, J. Kleynhans, J. Moyes, M. du Plessis, M. Carrim, F.K. Treurnicht, O. Hellferscee, T. Mkhencele, A. Mathunjwa, C. Cohen, A. von Gottberg, N. Wolter); Centers for Disease Control and Prevention, Atlanta, Georgia, USA (S. Tempia, M.L McMorrow); Johns Hopkins University, Baltimore, Maryland, USA (N.A. Martinson); National Research Foundation, Pretoria, South Africa (N.A. Martinson); South African Medical Research Council, Cape Town, South Africa (N.A. Martinson, K. Kahn, L. Lebina, K. Mothlaoleng, F. Wafawanaka, A. Mathee); North-West University, Potchefstroom, South Africa (S. Piketh)

Main Article

Incidence rate and factors associated with Bordetella pertussis incidence for 1,684 participants in the PHIRST study of respiratory infections, South Africa, 2016–2018*

Characteristic	B. pertussis incidence (95% CI)	Univariate analysis		Multivariable analysis
Characteristic	B. pertussis incidence (95% CI)	Incidence rate ratio (95% CI)	p value	Adjusted incidence rate ratio (95% CI)	p value
Overall	0.2 (0.17–0.25)	NA	NA	NA	NA
Year
2016	0.25 (0.17–0.35)	Referent		NA	NA
2017	0.13 (0.09–0.19)	0.53 (0.17–1.63)	0.27	NA	NA
2018	0.26 (0.20–0.33)	1.04 (0.44–2.49)	0.92	NA	NA
Site
Rural	0.17 (0.13–0.22)	Referent		NA	NA
Urban	0.24 (0.19–0.31)	1.5 (0.77–2.96)	0.23	NA	NA
Sex
M	0.23 (0.17–0.30)	Referent		NA	NA
F	0.19 (0.15–0.24)	0.83 (0.58–1.19)	0.31	NA	NA
Age group, y
<5	0.21 (0.14–0.33)	1.41 (0.69–2.90)	0.37	1.62 (0.56–4.65)	0.37
5–14	0.27 (0.20–0.35)	1.76 (0.96–3.21)	0.09	1.73 (0.91‒3.31)	0.09
15–44	0.17 (0.12–0.24)	1.12 (0.62–2.04)	0.78	1.09 (0.59–2.00)	0.78
>45	0.15 (0.09–0.25)	Referent		Referent
HIV status
Uninfected	0.22 (0.18–0.27)	Referent		NA	NA
Infected	0.14 (0.08–0.25)	0.64 (0.36–1.11)	0.11	NA	NA
Nutritional status†
Underweight	0·20 (0.10–0.38)	0.68 (0.28–1.66)	0.39	NA	NA
Normal	0.23 (0.18–0.28)	Referent		NA	NA
Overweight/obese	0.30 (0.21–0.43)	0.76 (0.52–1.13)	0.18	NA	NA
Underlying illness‡
No	0.20 (0.17–0.24)	Referent		NA	NA
Yes	0.36 (0.16–0.80)	1.78 (0.68–4.70)	0.24	NA	NA
Pertussis vaccination§
Incomplete	0.91 (0.23–3.64)	4.89 (1.47–16.02)	0.01	4.48 (1.38–14.59)	0.01
Fully vaccinated	0.19 (0.11–0.32)	Referent		Referent
Unknown	0.20 (0.17–0.25)	1.08 (0.61–1.91)	0.78	1.32 (0.42–4.13)	0.64
Crowding¶
No	0.15 (0.11–0.21)	Referent		Referent
Yes	0.25 (0.20–0.31)	1.63 (0.86–3.08)	0.13	1.53 (0.78–2.97)	0.21

*Bold indicates statistical significance. Variables adjusted for in final model were age group, pertussis vaccination, and crowding. NA, not applicable; PHIRST, Prospective Household cohort study of Influenza, Respiratory Syncytial virus, and other respiratory pathogens community burden and Transmission dynamics in South Africa. †Nutritional status is based on a person’s body mass index (BMI). We defined BMI categories as follows: underweight, age <18 y weight for age or BMI <‒2 SDs of World Health Organization (WHO) Child Growth Standards; age >18 y BMI <18.5 kg/m²; overweight, age <18 y BMI >+1 and ≤+2 SD of the WHO growth standards, age ≥18 y BMI ≥25 and <30 kg/m²; obese, age <18 y BMI >+2 SD of WHO growth standards, age ≥18 y BMI >30 kg/m². ‡Defined as self-reported history of asthma, lung disease, heart disease, stroke, spinal cord injury, epilepsy, organ transplant, immunosuppressive therapy, organ transplantation, cancer, liver disease, renal disease, or diabetes. §Collected only for children <5 y of age· Vaccine status calculate based on number of doses of vaccine received by age. ¶More than 2 persons in a household sleeping in the same room.

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Page updated: January 21, 2023

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