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Immunization schedule

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Routine service delivery is the bedrock of any immunization system. In African countries, routine immunization is delivered through the Expanded Programme on Immunization. Global disease control, elimination and eradication efforts depend on strong routine immunization systems, so routine immunization coverage is a good indication of the strength of a national health system.

The immunization schedule recommended by WHO in African countries starts with the Bacille Calmette-Guérin (BCG) and oral polio vaccine (OPV) at birth, followed by diphtheria-tetanus-pertussis (DPT), OPV, Haemophilus influenzae type b (Hib) and hepatitis B (HepB) at 6 weeks, 10 weeks and 14 weeks. Finally, immunization for measles and yellow fever is done at 9 months.

African countries have made great progress in increasing routine immunization coverage rates, but the ambitious Global Immunization Vision and Strategy coverage goals have not yet been reached. Routine immunization coverage for three doses of DPT (DPT3) increased dramatically in the WHO African Region from 2000, when DPT3 coverage was 54%, to 2007 when it stood at 82%.

DPT3 is used as a surrogate for routine immunization coverage. The rates cited are based on the official country estimates reported in the annual Joint Reporting Form. The WHO/United Nations Children's Fund (UNICEF) estimates of DPT3 coverage in the Region were, by contrast, 54% in 2000, 66% in 2004 and 74% in 2007. Because they are based on the official country estimates and the most recent population-based survey results, the WHO/UNICEF estimates are normally lower than the official country estimates.

In 2009, the regional coverage for the third dose of DPT3 was 85%, compared with 82% in 2008. Twenty countries reported at least 90% coverage at national level in 2009, compared with 17 in 2008.

Detailed analysis reveals disparities between and within countries. It is estimated that a total of 4.2 million children throughout the Region did not receive DPT3 vaccine in 2009, compared with 5.2 million in 2008,[1] and that an estimated 80% of these DPT3 under-immunized children reside in only 10 countries (Angola, Cameron, Côte d’Ivoire, Democratic Republic of the Congo, Ethiopia, Kenya, Nigeria, United Republic of Tanzania, Uganda, Zimbabwe).

Achievements against regional targets and other common routine immunization indicators. DTP3, three doses of diphtheria, pertussis and tetanus. 2004 data from Regional Expanded Programme on Immunization Strategic Plan Review

Among the various challenges in routine immunization noted by an external review in 2004 were continuing disparities in immunization coverage at national and subnational levels. DPT3 coverage rates were below 50% in many countries and districts across the Region. Vaccine stock-outs were affecting some countries, health facilities were inadequately equipped and staffed, and gaps were identified in the areas of immunization safety and waste management.

Achieving high levels of population immunity depends on effective routine immunization coverage, and the availability of additional vaccine doses during supplementary immunization activities. Some previously polio-free countries in west and central Africa experienced a resurgence of poliovirus transmission in 2008─2009. Contributing factors include:

  • the inability to achieve optimal coverage during supplementary immunization activities against a background of low routine immunization coverage;
  • disconnection between required activities and available resources;
  • limited sense of ownership and accountability by national and subnational authorities.

Suboptimal routine immunization appears to have contributed to measles outbreaks in many countries in the Region, calling into question the accuracy of some coverage estimates.

In search of new ways to help countries with weak immunization services and low coverage, the WHO Regional Office for Africa and key partners met in 2002 to identify common obstacles to increasing immunization coverage. As a result, the Reaching Every District (RED) Strategy was developed. The five elements of the strategy represent the repackaging and refocusing at district level of critical elements involved in successful routine immunization. The RED strategy components are:

  • planning and management of resources
  • reaching target populations
  • linking services with communities
  • supportive supervision
  • monitoring and use of data for action.

The implementation of the RED approach, together with other innovative strategies such as the Periodic Intensification of Routine Immunization activities, Child Health Days and Immunization Plus Days, have all contributed to improving coverage. In conflict-riven and post-conflict countries, as well as in geographically and culturally hard-to-reach zones, a tailored mix of fixed, outreach and Periodic Intensification of Routine Immunization activities has been key for achieving national and regional coverage goals.

The Regional Office is currently focusing on improving routine immunization performance by:

  • prioritizing countries with large numbers of non-immunized or under-immunized children
  • implementing the revised 2008 RED approach and other innovative strategies
  • improving data quality in programme monitoring
  • using the opportunity provided by the introduction of new vaccines to strengthen immunization systems
  • continuing to train immunization workers to enhance their competence
  • mobilizing resources to close funding gaps.

Efforts continue to improve data quality and use, and an expanded set of coverage indicators has been developed. Both measures will be increasingly important as countries seek and adopt more effective approaches to increasing, sustaining and monitoring routine immunization coverage.

The recent progress in immunization in the African countries was largely made possible due to the availability of international funding, with modest contributions from countries themselves. Eighty five per cent of countries have specific budgets for vaccines procurement. The proportion of government expenditure on vaccines in the Region increased from 48% in 2000 to 53% in 2006, although expenditure on overall routine immunization remained largely unchanged from 45% in 2000 and 43% in 2006.[2]

References

  1. Ministry of Health─United Nations Children's Fund─WHO Joint Reporting Forms
  2. Lyndon P et al. Government financing for health and specific national budget lines: the case of vaccines and immunization. Vaccine, 2008, 26: 6727─6734