Measles control in Sub-Saharan Africa: South Africa as a case study

Background

Due to intensified measles immunization efforts, measles mortality has decreased substantially worldwide, particularly in Sub-Saharan Africa (SSA). The World Health Organization (WHO) estimated a 92% decrease in measles-related deaths in the WHO AFRO region for the period 2000–2008. Recently, the AFRO region established a measles pre-elimination goal and experts have suggested engaging in a measles eradication campaign at the global level. However, recent large-scale outbreaks in many Sub-Saharan African countries present a challenge to measles control efforts. This paper examines measles immunization and the impact of measles supplemental immunization activities (SIAs) on routine immunization coverage in South Africa (SA).

Methods

We reported on immunization coverage trends in SA for the period 2001–2010 at the province and district levels. The data included routine immunization for 1st and 2nd doses of measles vaccine (MCV1, MCV2), SIAs, 1st dose of Bacille Calmette-Guérin vaccine, 1st and 3rd doses of oral polio vaccine (OPV1, OPV3), 3rd dose of Diphtheria–Tetanus–Pertussis–Haemophilus-influenzae-B vaccine (DTP-Hib3), and the number of under-one-year-olds having completed a primary course of immunization (Imm1). A regression model looked at the SIA impact on routine coverage.

Results

Over the past decade, MCV1 and MCV2 coverage have increased nationally from 68% and 57% in 2001 to 95% and 83% in 2010, respectively. SIA coverage has remained at high levels, around 90%, over the same period. Substantial heterogeneity in MCV1 and MCV2 coverage is present across SA districts, with differences in coverage of 56% (MCV1) and 51% (MCV2) in 2010. In any given year, occurrence of SIAs was associated with a decrease in routine immunization coverage of MCV1, MCV2, OPV1, OPV3, DTP-Hib3, and Imm1, at the district level.

Conclusions

The heterogeneity in measles vaccination coverage across SA districts challenges the goal of measles elimination in SA and SSA. The reduction in routine immunization coverage associated with the occurrence of SIAs raises the legitimate concern that SIAs may negatively impact health systems’ functioning.     

Long-term immunogenicity and efficacy of a 9-valent conjugate pneumococcal vaccine in human immunodeficient virus infected and non-infected children in the absence of a booster dose of vaccine

The long-term immunogenicity and vaccine efficacy (VE) of a 9-valent conjugate pneumococcal vaccine was studied in HIV infected and HIV non-infected children. VE against vaccine-serotype invasive pneumococcal disease following 6.16 years of follow-up persisted in HIV non-infected children (77.8%; 95% CI 34.4-92.5 compared to 83% after 2.3 years of follow-up), and declined from 65% to 38.8% (95% CI -7.8 to 65.2) in HIV infected children. HIV non-infected vaccinees had equal (serotypes 4, 6B, 14, 19F) or greater (serotypes 9V, 18C, 23F) proportions of serotype-specific antibody concentrations of > or =0.2microg/ml to vaccine-serotypes analyzed compared to HIV infected vaccinees at 5.3 years of age.     

Rodent control in urban communities in Johannesburg,South Africa: from research to action

Introduction:

Rodents are troublesome urban pests, with potentially serious health implications. Preventive efforts require greater understanding of social contexts in which they are prevalent. This study aimed to determine rodent prevalence and identify factors associated with rodent infestations in urban residential settings.

Methods:

The Health, Environment and Development study is a longitudinal panel study conducted in five settlements across Johannesburg. Data on socio-economic status, domestic behaviour and housing quality are collected annually. Logistic regression revealed risk factors for rodent prevalence at household level.

Results:

Rodents are a major household problem in all study areas (prevalence 54%). Factors associated with increased prevalence of rats included lower income, living in informal areas, overcrowding, cracks in dwelling walls and internal damp.

Conclusion:

Socio-economic status, housing quality, domestic behaviour and environmental health services are associated with exposure to rodents in urban Johannesburg communities. This information served as a platform to launch rodent awareness campaigns at study sites.