Journal of immunological sciences最新文献

Background: Measles elimination is defined as the absence of endemic measles virus transmission in a defined geographic area for at least 12 months in the presence of a well-performing surveillance system. The WHO framework for verification of measles elimination indicates that the achievement of measles and/or rubella elimination should be verified for individual countries.

Objective: We identified 11 high performing countries based on their first dose measles vaccination coverage, and looked at their performance across the various programmatic parameters, to see if they are ready to undertake the verification of measles elimination.

Methods: We identified 11 countries with >90% measles first dose coverage for the most recent 5 years according to the WHO UNICEF estimates of national immunisation coverage. We analysed vaccination coverage and surveillance performance in these countries.

Results: Algeria, Botswana, Gambia, Mauritius, Rwanda, Seychelles have maintained measles first dose (MCV1) coverage of 95% or more since 2011. In 2015, only Algeria, Cape Verde and Seychelles had coverage of 95% or more for the second dose of measles vaccine (MCV2). Of the 22 supplemental immunisation activities (SIAs) among the 11 countries, only 6 had administrative coverage of less than 95%. Only Rwanda and Lesotho attained the case-based surveillance performance targets in all the five years.

Conclusion: Despite their high routine first dose measles immunisation coverage, all of the 11 countries have some program gaps indicating that they do not meet all the criteria to undergo verification of elimination at this point. It is recommended for these countries to set up national verification committees as per the WHO framework for verification of measles elimination, in order to initiate the documentation and monitoring of progress, and to address programmatic gaps in the coming years.

Background: WHO recommends all countries to include a second routine dose of measles containing vaccine (MCV2) in their national routine vaccination schedules regardless of the level of coverage with the first routine dose of measles containing vaccine (MCV1). As of Dec 2016, 26 countries in the African Region have introduced MCV2.

Methods: We reviewed the WHO UNICEF coverage estimates for MCV1 and MCV2 in these countries, and the reports of the post introduction evaluation of MCV2 from 11 countries.

Results: Twenty three countries have WHO/UNICEF estimates of MCV2 coverage available in 2015. Of these, 2 countries have coverage of ≥ 95% for both MCV1 and MCV2 while 5 countries have coverage of > 80% for both doses. Dropout rates of >20% MCV1 - MCV2 exist in 12 countries. Post-MCV2 introduction evaluations done in 11 countries from 2012 to 2015 showed that inadequate health worker training, insufficient sensitization and awareness generation among parents and suboptimal dose recording practices were common programmatic weaknesses that contributed to the low MCV2 coverage in these countries.

Conclusion: MCV2 coverage remains low as reflected in large drop-out rates in most countries. Higher MCV2 coverage is necessary to sustainably achieve the regional measles elimination goal. National immunization programs must improve implementation of MCV2 using the standard introduction and evaluation guidelines available for EPI program planning.

The World Health Organization (WHO) recommends that countries introduce rubella containing vaccines (RCVs) to reduce rubella circulation and the occurrence of congenital rubella syndrome (CRS). As of June 2017, a total of 18 countries have already introduced or are in the process of introducing RCV in routine child vaccination programs. RCV introduction during 2013 - 2014 in five countries in the Region resulted in a reduction of rubella incidence of 48% to 96% in the post-introduction period as compared to the average incidence in the years before introduction. These results suggest that initial mass vaccination campaigns and introduction of RCVs in routine immunization programs result in significant reduction in rubella incidence and a reduced potential for the occurrence of CRS.