Vaccination timing of low-birth-weight infants in rural Ghana: a population-based, prospective cohort study.
OBJECTIVE
To investigate delays in first and third dose diphtheria-tetanus-pertussis (DTP1 and DTP3) vaccination in low-birth-weight infants in Ghana, and the associated determinants.


METHODS
We used data from a large, population-based vitamin A trial in 2010-2013, with 22 955 enrolled infants. We measured vaccination rate and maternal and infant characteristics and compared three categories of low-birth-weight infants (2.0-2.4 kg; 1.5-1.9 kg; and < 1.5 kg) with infants weighing ≥ 2.5 kg. Poisson regression was used to calculate vaccination rate ratios for DTP1 at 10, 14 and 18 weeks after birth, and for DTP3 at 18, 22 and 24 weeks (equivalent to 1, 2 and 3 months after the respective vaccination due dates of 6 and 14 weeks).


RESULTS
Compared with non-low-birth-weight infants (n = 18 979), those with low birth weight (n = 3382) had an almost 40% lower DTP1 vaccination rate at age 10 weeks (adjusted rate ratio, aRR: 0.58; 95% confidence interval, CI: 0.43-0.77) and at age 18 weeks (aRR: 0.63; 95% CI: 0.50-0.80). Infants weighing 1.5-1.9 kg (n = 386) had vaccination rates approximately 25% lower than infants weighing ≥ 2.5 kg at these time points. Similar results were observed for DTP3. Lower maternal age, educational attainment and longer distance to the nearest health facility were associated with lower DTP1 and DTP3 vaccination rates.


CONCLUSIONS
Low-birth-weight infants are a high-risk group for delayed vaccination in Ghana. Efforts to improve the vaccination of these infants are warranted, alongside further research to understand the reasons for the delays.
Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel St, London, WC1E 7HT, England .
Maureen
M
O'Leary
Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel St, London, WC1E 7HT, England .
Sara
S
Thomas
Institute of Primary Care and Public Health, University of Cardiff, Cardiff, Wales .
Lisa
L
Hurt
Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel St, London, WC1E 7HT, England .
Sian
S
Floyd
Engender Health, New York, United States of America (USA).
Caitlin
C
Shannon
Department of Community Health, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana .
Sam
S
Newton
Kintampo Health Research Centre, Kintampo, Ghana .
Gyan
G
Thomas
Kintampo Health Research Centre, Kintampo, Ghana .
Seeba
S
Amenga-Etego
Kintampo Health Research Centre, Kintampo, Ghana .
Charlotte
C
Tawiah-Agyemang
Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel St, London, WC1E 7HT, England .
Lu
L
Gram
Institute of Cancer and Genetics, University of Cardiff, Cardiff, Wales .
Chris
C
Hurt
Department of Maternal, Newborn, Child and Adolescent Health, World Health Organization, Geneva, Switzerland .
Rajiv
R
Bahl
Kintampo Health Research Centre, Kintampo, Ghana .
Seth
S
Owusu-Agyei
Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel St, London, WC1E 7HT, England .
Betty
B
Kirkwood
School of Paediatrics and Child Health, University of Western Australia, Crawley, Australia .
Karen
K
Edmond
D000328:Adult; D005260:Female; D005869:Ghana; D006801:Humans; D007115:Immunization Schedule; D007230:Infant, Low Birth Weight; D008297:Male; D016012:Poisson Distribution; D011446:Prospective Studies; D012424:Rural Population; D055815:Young Adult