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Predictors of Uptake and Timeliness of Newly Introduced Pneumococcal and Rotavirus Vaccines, and of Measles Vaccine in Rural Malawi: A Population Cohort Study

Sunday, 8th of May 2016

Predictors of Uptake and Timeliness of Newly Introduced Pneumococcal and Rotavirus Vaccines, and of Measles Vaccine in Rural Malawi: A Population Cohort Study

• Hazzie Mvula ,
• Ellen Heinsbroek ,
• Menard Chihana,
• Amelia C. Crampin,
• Storn Kabuluzi,
• Geoffrey Chirwa,
• Charles Mwansambo,
• Anthony Costello,
• Nigel A. Cunliffe,
• Robert S. Heyderman,
• Neil French,
• Naor Bar-Zeev ,
• VacSurv Consortium 

 

Abstract below; full text is at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0154997

 

Background

Malawi introduced pneumococcal conjugate vaccine (PCV13) and monovalent rotavirus vaccine (RV1) in 2011 and 2012 respectively, and is planning the introduction of a second-dose measles vaccine (MV). We assessed predictors of availability, uptake and timeliness of these vaccines in a rural Malawian setting.

Methods

Commencing on the first date of PCV13 eligibility we conducted a prospective population-based birth cohort study of 2,616 children under demographic surveillance in Karonga District, northern Malawi who were eligible for PCV13, or from the date of RV1 introduction both PCV13 and RV1. Potential predictors of vaccine uptake and timeliness for PCV13, RV1 and MV were analysed respectively using robust Poisson and Cox regression.

Results

Vaccine coverage was high for all vaccines, ranging from 86.9% for RV1 dose 2 to 95.4% for PCV13 dose 1. Median time delay for PCV13 dose 1 was 17 days (IQR 7–36), 19 days (IQR 8–36) for RV1 dose 1 and 20 days (IQR 3–46) for MV. Infants born to lower educated or farming mothers and those living further away from the road or clinic were at greater risk of being not fully vaccinated and being vaccinated late. Delays in vaccination were also associated with non-facility birth. Vaccine stock-outs resulted in both a delay in vaccine timeliness and in a decrease in completion of schedule.

Conclusion

Despite high vaccination coverage in this setting, delays in vaccination were common. We identified programmatic and socio-demographic risk factors for uptake and timeliness of vaccination. Understanding who remains most vulnerable to be unvaccinated allows for focussed delivery thereby increasing population coverage and maximising the equitable benefits of universal vaccination programmes.

Citation: Mvula H, Heinsbroek E, Chihana M, Crampin AC, Kabuluzi S, Chirwa G, et al. (2016) Predictors of Uptake and Timeliness of Newly Introduced Pneumococcal and Rotavirus Vaccines, and of Measles Vaccine in Rural Malawi: A Population Cohort Study. PLoS ONE 11(5): e0154997. doi:10.1371/journal.pone.0154997

 

Introduction

Malawi has proactively pursued the fourth Millennium Development Goal of reducing child mortality which it is expected to meet [1]. The early adoption of thirteen-valent pneumococcal conjugate (PCV13) and monovalent rotavirus (RV1) vaccines has been part of this strategy, with introductions on 12^th November 2011 and 29^th October 2012 respectively. PCV13 and RV1 are given according to World Health Organisation (WHO) recommended schedule at 6 and 10 weeks for doses 1 and 2, and 14 weeks for third dose PCV13 along with Pentavalent vaccine (diphtheria, pertussis, tetanus, Haemophilus influenzae type B and hepatitis B) and oral polio. Initial catch-up vaccination for PCV13 was conducted at the time of introduction with infants <1 year of age at date of first dose to receive 3 doses at 1 month intervals, even if subsequent doses would be given in the second year of life. Currently no PCV booster is scheduled. Measles vaccine (MV) is currently given as a single dose at 9 months of age, but a number of African countries including Malawi are planning introduction of a second dose [2]. Nationwide and district level MV campaigns are conducted when necessary. In our study site in Karonga district there have been four MV campaigns among infants <1 year of age between 2011 and 2014; one in 2011 and three in 2014.

Vaccination remains the cornerstone of public health intervention to reduce childhood morbidity and mortality, but oftentimes there are select groups that achieve poorer coverage than the national average [3]. Furthermore, vaccine coverage estimates do not reflect timeliness of vaccination, which may frequently be delayed [4, 5]. Previous work in this setting prior to introduction of PCV1 and RV1 showed high uptake of vaccines but delays in schedule [6]. As part of a national evaluation of impact and effectiveness of new vaccines in Malawi [7], we analysed data from a population-based birth cohort study to investigate factors affecting vaccination coverage and timeliness in northern Malawi during the period of introduction of pneumococcal and rotavirus vaccines. We also took the opportunity to examine predictors of MV coverage and timeliness with a view to informing national considerations of introduction of a second dose.