Data were obtained from the 2015-16 Malawi Demographic and Health Survey (MDHS). Methods used in this study has been described in details elsewhere 5. Briefly, the 2015-16 MDHS employed two-staged probability sampling and produced a nationally representative sample. Firstly, 850 standard enumeration areas (SEAs), including 173 SEAs in urban areas and 677 in rural areas. SEAs were selected with probability proportional to the size and independent selection in each sampling stratum.
Secondly, a fixed number of 30 households per urban cluster and 33 per rural cluster were selected with an equal probability systematic selection from the newly created household listing. Data collectionUsing face-to-face interviews, data were collected from women aged 15–49 years with children below the age of 5 years prior to the survey on the measures of population health, sociodemographic, environmental, anthropometry, and HIV/AIDS, immunization, and child health care indicators. Information on rotavirus and pneumococcal conjugate vaccines were obtained in two ways. Mothers were asked to show whether they had a vaccination card for each child born 5 years prior to the data collection.
If the mother could not show an immunization card, she was then asked to report whether the child had received any vaccination.MEASURESOutcome variablesThe outcome variables of this study were a pneumococcal vaccine and rotavirus vaccine uptake. Vaccination uptake was defined as children aged 12-35 months had received three doses of the pneumococcal vaccine and two doses of the rotavirus vaccine before their first birthday. Furthermore, to avoid the clustering effects of children from same households, a random procedure was applied to select one child per mother. Independent variablesChild-specific factors included child’s sex (male or female), the birth order (1, 2–3, 4–5, and ? 6) and place of delivery (home and other, hospital/institution).
Maternal and household characteristics included age in years (15–24, 25–34), educational attainment (no formal education, primary, secondary education and above), employment status (no formal employment, white collar, and blue collar), household wealth status (poorest, middle, and richest), perceived distance to health facility (no big problem, big problem). The number of under-5-year children in the household (?1, 2–3, and ? 4), the number of antenatal care visits (no visits, inadequate visits, and adequate visits), vaccination card (no card/no longer has card, has card but not seen, and has card and seen), place of residence (urban or rural), and geographical region (northern, central, and southern). The wealth index was constructed using data on a household’s ownership of selected assets, such as televisions, materials used for constructing the house etc., through the principal component analysis.
Statistical analysesAll analyses were performed using SAS software version 9.4 (SAS Institute, Cary, NC, USA) 14. The multivariate analyses were conducted using a series of two-level logistic models (e.g., children and Maternal /households) with generalized estimating equations (GEEs) for estimating the effects of the predictors of the uptake of the pneumococcal and rotavirus vaccines.
GEE models were used to adjust the correlated individual responses due to the complex design of the data structure. Results of the multivariate analysis were reported as adjusted odds ratio (aORs) with p values and 95% confidence intervals. The significance level of alpha was set to 5%.Ethics statementThe 2015-16 MDHS was implemented by the National Statistics Of?ce (NSO) and the Community Health Sciences Unit (CHSU). The protocol for the questionnaires was reviewed and approved by the Malawi Health Sciences Research Committee, the Institutional Review Board of ICF Macro, and the Centers for Disease Control (CDC) in Atlanta. Informed consent was obtained at the beginning of each interview and the authors sought permission from the DHS program for the use of the data.