Overview of Wild Poliovirus Epidemiology In Nigeria

This PowerPoint presentation was part of a June 2007 United Nations Children's Fund (UNICEF)-hosted meeting dedicated to examining polio communication efforts, in the context of the final global push towards polio eradication. State-specific presentations for Nigeria’s polio-endemic states were given by in-country communication and health practitioners. These were assessed by an external Technical Advisory Group (TAG) panel of experts who provided communication strategy recommendations based on evidence presented and data gathered on field-visits to endemic states. Communication strategies presented at this meeting were primarily focused on:

1. Analysing the results of programmes implemented to June 2007.
2. Detailing activities on national and sub-national levels, specific to social mobilisation, community engagement, data monitoring and media and political advocacy strategies.
3. Suggesting a planned communication programme for the next 6- to 12-month period, designed to support Nigeria’s polio eradication efforts in the event of a resurgence of cases or population/programme fatigue.

This presentation was given by Dr. Pascal Mkanda of the World Health Organization (WHO) and describes the current wild poliovirus (WPV) situation in Nigeria. It discusses whether Nigeria has made any progress in achieving transmission interruption, and goes on to outline the challenges to interruption transmission of the disease and the proposed way forward through these challenges.



As of June 26 2007, Nigeria has 114 cases of WPV in 19 states, as compared to 565 cases in the same period in 2006. A significant improvement in the number of states meeting both Acute Flaccid Paralysis (AFP) core performance indicators has also been seen, with an increase from 73% in 2006 to 95% in 2007.



Trends indicate that onset rates for both WPV Type 1 and Type 3 strains have decreased in recent years, including in the highest-risk states. A current challenge is to further reduce the proportion of un-vaccinated children and enhance population immunity, as an increasing proportion of cases in 2007 are occurring in individuals who have had 1 to 2, and in some cases over 3 doses of vaccine.



Further challenges include addressing border issues between states. About 85% of the polio-afflicted local government areas (LGAs) are in the borders between states. The settlements bordering LGAs or wards are most affected. In addition, riverine and hard-to-reach areas and those generally underserved by routine immunisation activities have high rates of WPV transmission.



In the high-risk states of Katsina and Jigawa, rural settings account for 75% of WPV cases, as opposed to 25% in urban settings. Inhabitants in these rural settings are predominantly farmers and middle-aged parents from the Hausa tribe, who do not lead nomadic lifestyles (no travel in past 30 days) and most of whom have a Koranic level of education. The profile of urban inhabitants is slightly different, consisting of Islamic teachers and civil servants who exhibit a greater rate of vaccination non-compliance, also belonging to the Hausa tribe and most of whom have a history of travel within the past 30 days.



In summary, significant progress has been made in 2007:

• There has been significant decline in total WPV burden in early 2007 (approx 80% for total WPV).
• A large reduction (approximately 95%) of WPV1 cases.
• Unlike in previous years, WPV3 - which is not as highly transmissable as WPV1 - is currently the largest burden of WPV in Nigeria. This offers a good opportunity for interruption of transmission.
• Significant geographical restriction of cases.

Circulation is still occurring mainly in areas that are missed by vaccination teams. The majority of this burden lies in rural, hard-to-read and underserved areas. In the areas where vaccination teams are active, children are still occasionally missed due to pockets of non-compliance, team performance, and inadequate micro-plans.



This presentation concludes with the following proposed ways to interrupt WPV transmission in Nigeria:

1. Continue to improve quality of Immunisation Plus Days (IPDs) through micro-planning, community mobilisation, supervision, logistics etc.
2. Use of additional innovations, particularly use of monovalent oral polio vaccine type 3 to control and interrupt upsurge of WPV3.
3. Conducting additional in-between rounds immunisation activities.
4. Strengthening routine immunisation.

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