Research evaluates progress
The Global Polio Eradication Initiative (GPEI) Strategic Plan 2010-2012 describes the usefulness of research in guiding the programme decisions in some of the endemic countries over the last years. The Strategic Plan recommends that the scope of research activities such as serosurveys, environmental surveillance, Lot Quality Assurance Sampling (LQAS) and better supplementary immunization activity (SIA) monitoring tools should be expanded to other key endemic areas.
Periodic serosurveys and adjusting programme decisions to achieve and maintain high population immunity have been recommended as a process indicator
towards the achievement of milestones. To this end, a seroprevalence study was done
in India in August 2010, one is ongoing in Pakistan and another being planned in Nigeria.
India seroprevalence 2010
India implemented a cross-sectional seroprevalence study in August 2010 in high-risk blocks of western Uttar Pradesh and central Bihar. Ten highest-risk blocks in each state were selected on the basis of highest polio rate and occurrence of polio cases in the last five years. Within these blocks, children aged 6-7 months were randomly selected from SIA microplans.
The implementation of this survey was a joint effort of the National and State Governments, National Polio Surveillance Project (NPSP) India, social mobilization network (SM net) of UNICEF and CORE, the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC). Screening and selection of study participants was done in the identified field areas by the SM net and Surveillance Medical Officers (SMOs). The selected study children and parents were enrolled at the nearest health facility. In addition to the blood sample for serology, the study infants and their mothers were offered tests for anaemia and were given iron and folic-acid supplementation to help address nutritional anaemia.
The response and participation was high in these most challenging areas of Uttar Pradesh and Bihar. Transportation of study children in the difficult terrain of Kosi river area was a clear logistic challenge. It was heartening to see that the parents agreed to travel across long distances on foot and used boats, motorcycles, carts and other means of transportation to reach the health facilities.
Overall, 1200 serum samples were collected, 60 from each block. Samples have been sent for testing to the Enterovirus Research Centre (ERC) in Mumbai. Results of serology are expected in early 2011, and will provide key insight into the prevailing levels of seroprevalence in high-risk areas of India. At the same time, results will help in evaluating the impact of use of bivalent oral polio vaccine (bOPV) in these traditional strong holds of polio transmission.
Nigeria seroprevalence 2011
There is a dramatic decline in the number of polio cases in Nigeria in 2010 as compared to the last year. Though there has been an overall improvement in SIA operations, the percentage of zero-dose children remains high in some key northern Nigerian states.
To assess the immunity profile of young children in the highest risk Local Government Areas (LGAs - districts), the GPEI partners have agreed to conduct a health facility-based seroprevalence study in the city of Kano, in the northern state of Kano.
The study protocol has been drafted and is under technical and ethical review. The study is likely to be implemented in early 2011 and the serology results should be available in the first quarter of 2011, and should provide key insight into ongoing immunity gaps and operational programme efficacy in northern Nigeria.