Journal of immunological sciences最新文献

Introduction: Rubella is a mild febrile rash illness caused by the rubella virus. The most serious consequence of rubella is congenital rubella syndrome (CRS), which occurs if the primary rubella infection occurs during early pregnancy, with subsequent infection of the placenta and the developing fetus.

Methods: WHO supported countries to set up sentinel surveillance for CRS using standard case definitions, protocols, and case classification scheme. This descriptive analysis summarises the data from 5 countries which have been regularly reporting.

Results: A total of 383 suspected cases of CRS were notified from the 5 countries as of December 2016, of which 52 cases were laboratory confirmed and 67 were confirmed on clinical grounds.The majority (43%) of confirmed CRS cases were in the age group 6 - 11 months. The most common major clinical manifestation (Group A) among the confirmed cases is congenital heart disease (72%) followed by cataracts (32%) and glaucoma (10%).

Discussion and conclusions: The number of years of reporting from these sentinel sites is too short to describe trends in CRS occurrence across the years. However, the limited surveillance data has yielded comparable information with other developing countries prior to introduction of rubella vaccine. As more countries introduce rubella vaccine into their immunisation programs, there is a need to ensure that all rubella outbreaks are thoroughly investigated and documented, to expand sentinel surveillance for CRS in more countries in the Region, and to complement this with retrospective record reviews for CRS cases in selected countries.

The 5^th edition of the African Vaccination Week (AVW) kicked off in Lusaka, Zambia, on 23 April 2016, the same day as did the 4th World Immunization Week (WIW), and vaccination week in other WHO regions. The theme was "Save lives, prevent disabilities, vaccinate!". The aim was to draw attention to the need to attain universal immunization coverage in the African Region by closing the immunization gap, while also celebrating the important polio eradication milestone reached in the African Region. Twenty-eight (59.6%) of the 47 countries in the African Region celebrated the AVW within the regionally set dates of 24^th to 30^th April 2015. However, given its flexibility, the celebration continued until September in 15 other countries in the Region. Three countries, namely Comoros, Gabon, and Cape Verde did not join the celebration for the 2015 edition of the AVW. Countries used the opportunity to introduce new vaccines into their routine immunization. Populations, hitherto unreached with basic health services were reached with needed services, such as vitamin A supplementation, deworming, and catch up immunization services. The programmes promoted awareness of the benefits of vaccines and the rights of communities to demand vaccines and immunization services to save lives and prevent disabilities. The number of participating countries rose steadily from 40 in 2011 to 43 and 46 countries in 2013 and 2014 respectively. The number ranged from one intervention integrated with AVW in 17 countries to 5 interventions integrated with the AVW in three countries. In 2015, 67.4% of the participating countries integrated other interventions with AVW activities.

Immunization programme has contributed to saving many lives from avoidable deaths and bring many other benefits, including healthier children, increased school attendance, and increased productivity. In the past 10 years, immunization as a public health intervention has expanded in target as well as number of vaccines to be delivered to a broader range of people and new vaccines. Immunization is also exceptionally of good value, returning many dollars in economic benefits for every dollar invested in immunization services. Healthy individuals are more productive, earn more, save more, invest more, consume more, and work longer: which all impact to increase a nation's GDP. Immunization is one of the most effective, and cost-effective, public health tools that contribute to this situation. Fully immunized children have better educational outcomes and, over time, make for a more productive workforce. Consequently immunization, which must be sustained indefinitely, as a long-term investment require stable, long-term financing. A start point is a plan which is translated into funding for the programme. In sustainability a detailed planning process that assures a review of the situation leading to detailed programming in terms of response to challenges and finally culminating in costing so that funding requirements are determined and mobilised cannot be overemphasized. The experience has been varied in Africa region. While governments have made significant strides to increase funding for immunization programs over the last five years, further commitment is needed to achieve full financing and national ownership of immunization programs. Most countries have adopted the Comprehensive Multi-year Planning framework for planning and are thus able to put together their resource needs for immunization programmes. To continue to have the necessary benefits of high coverage and cover the increased investment requirements governments will need to do more to assure robust funding in a sustainable and predictable manner. The paper tells the story of importance of planning using the cMYP processes to immunization financing sustainability as a necessary condition in the trajectory towards sustainability. This article presents the experience of countries from planning to funding, drawing on the interconnectedness of adequate planning, ability to mobilise resources and thus better move towards sustainable funding. As governments pursue high level order of planning, they are in a better position to stem overdependence on Gavi and other external support for future sustainability.

Tetanus is a vaccine-preventable disease of significant public health importance especially in developing countries. The WHO strategy for the elimination of maternal and neonatal tetanus recommends the promotion of clean delivery practices, systematic immunization of pregnant women and those in the reproductive age (15-49 years) and surveillance for neonatal tetanus. Implementation of the recommended strategy with the support of WHO, UNICEF and other partners has led to significant decline in number of cases and deaths due to NT over the last decades. The coverage with the second or more dose of tetanus toxoid-containing vaccines (TT2+) a proxy for Protection at Birth (PAB) for the WHO African region has risen from 62% in 2000 to 77% by 2015 Reported cases of NT declined from 5175 in 2000 to 1289 in 2015. The goal of eliminating maternal and neonatal tetanus by 2015 was missed, but some progress has been made. By the end of 2016, 37 out of 47 (79%) of the WHO AFR member states achieved elimination. The 10 member states remaining need additional support by all partners to achieve and maintain the goal of MNTE. Innovative ways of implementing the recommendations need to be urgently considered.

Introduction: Nigeria has adopted the African Regional measles elimination targets and is implementing the recommended strategies. Nigeria provides routine measles vaccination for children aged 9 months. In addition, since 2006, Nigeria has been conducting nationwide measles supplemental Immunisation activities (SIAs) or mass vaccination campaigns every 2 years, and has established measles case-based surveillance.

Methods: We reviewed routine and supplemental measles immunization coverage data, as well as measles case-based surveillance data from Nigeria for the years 2012 - 2016, in an attempt to determine the country's progress towards these elimination targets.

Results: The first dose measles vaccination coverage in Nigeria ranged from 42% and 54% between 2012 and 2015, according to the WHO UNICEF national coverage estimates. Nigeria achieved 84.5% coverage by survey following the 2015 nationwide measles supplemental immunisation activities (SIAs). During this period, the incidence of confirmed measles ranged from 25 - 300 confirmed cases per million population per year, with the Northern States having significantly higher incidence as compared to the Southern States. At the same time, the pattern of confirmed cases indicated a consistent shift in epidemiological susceptibility including older age children.

Conclusions: In order to accelerate its progress towards the measles elimination targets, Nigeria should build population immunity on a sustainable basis by addressing systemic issues in order to scale up routine immunisation coverage, especially in the Northern half of the country; tailoring the target age for measles SIAs so as to sharply reduce measles incidence in age groups heavily affected by the disease; effectively mobilising resources and improving the quality of planning and coverage outcome of SIAs.

Background: Some progress has been made in expanding immunization in the African Region over the last four decades. However, an estimated 22% of the eligible children in the African Region, located in four countries of the African Region (Democratic Republic of the Congo, Ethiopia, Nigeria and South Africa), continue to miss vaccination services for various reasons. This paper documents the status of routine immunization in the African Region.

Methods: Programme records, reports and statistics were reviewed for this paper.

Results: Challenges remain in reaching an estimated 20-30% of children across the Region. In addition to the traditional vaccines (DTP, measles, polio and tuberculosis) newer ones, such as for Pneumococcal conjugate vaccine (PCV) and rotavirus, are being rolled out in the Region but uptake and coverage are slow and patchy both within and between countries.

Conclusion: The new regional strategic plan for immunization 2014-2020 is intended to provide policy and programmatic guidance to Member States, in line with the 2011-2020 Global Vaccine Action Plan (GVAP), in order to optimize immunization services and assist countries to further strengthen their immunization programmes.

Introduction: Few African countries have introduced a birth dose of hepatitis B vaccine (HepB-BD) despite a World Health Organization (WHO) recommendation. HepB-BD given within 24 hours of birth, followed by at least two subsequent doses, is 90% effective in preventing perinatal transmission of hepatitis B virus. This article describes findings from assessments conducted to document the knowledge, attitudes, and practices surrounding HepB-BD implementation among healthcare workers in five African countries.

Methods: Between August 2015 and November 2016, a series of knowledge, attitude and practices assessments were conducted in a convenience sample of public and private health facilities in Botswana, the Gambia, Namibia, Nigeria, and São Tomé and Príncipe (STP). Data were collected from immunization and maternity staff through interviewer-administered questionnaires focusing on HepB-BD vaccination knowledge, practices and barriers, including those related to home births. HepB-BD coverage was calculated for each visited facility.

Results: A total of 78 health facilities were visited: STP 5 (6%), Nigeria 23 (29%), Gambia 9 (12%), Botswana 16 (21%), and Namibia 25 (32%). Facilities in the Gambia attained high total coverage of 84% (range: 60-100%) but low timely estimates 7% (16-28%) with the median days to receiving HepB-BD of 11 days (IQR: 6-16 days). Nigeria had low total (23% [range: 12-40%]), and timely (13% [range: 2-21%]) HepB-BD estimates. Facilities in Botswana had high total (94% [range: 80-100%]), and timely (74% [range: 57-88%]) HepB-BD coverage. Coverage rates were not calculated for STP because the maternal Hepatitis B virus (HBV) status was not recorded in the delivery registers. The study in Namibia did not include a coverage assessment component. Barriers to timely HepB-BD included absence of standard operating procedures delineating staff responsible for HepB-BD, not integrating HepB-BD into essential newborn packages, administering HepB-BD at the point of maternal discharge from facilities, lack of daily vaccination services, sub-optimal staff knowledge about HepB-BD contraindications and age-limits, lack of outreach programs to reach babies born outside facilities, and reporting tools that did not allow for recording the timeliness of HepB-BD doses.

Discussion: These assessments demonstrate how staff perceptions and lack of outreach programs to reach babies born outside health facilities with essential services are barriers for implementing timely delivery of HepB-BD vaccine. Addressing these challenges may accelerate HepB-BD implementation in Africa.

Case based surveillance for measles is implemented in the African Region integrated with Acute Flaccid Paralysis (AFP) surveillance. In 2011, the Region adopted a measles elimination goal to be achieved by 2020, which included coverage, incidence and surveillance performance targets. We reviewed measles case-based surveillance data and surveillance performance from countries in the African Region for the years 2012 - 2016. During this period, a total of 359,019 cases of suspected measles were reported from the 44 of 47 (94%) countries using the case based surveillance system. Of these, 202,126 (56%) had specimens collected for laboratory testing. A total of 39,806 measles cases and 25,679 rubella cases were confirmed by IgM serology. Twelve countries met the two principal surveillance performance indicators for each year during the period and four countries met neither indicator over the period. At the Regional level, both surveillance targets were met in 3 of the 5 years in the period of study; however performance varies widely by country. Surveillance performance did not improve across the Region during the 5 years period. High quality surveillance performance is critical to support the achievement of the regional measles elimination goal. Better integrating implementation with AFP surveillance, securing predictable long-term funding sources, and conducting detailed evaluations at country level to identify and address the root cause of performance gaps is recommended.

Objective: This article summarises the progress made since the introduction of environmental surveillance in the African Region.

Method: Country selection was based on the poor AFP performance indicators i.e. Non polio AFP rate and stool adequacy. It was recommended that any country not meeting the required indicators should consider environmental surveillance activity as an additional tool to support AFP surveillance. The sites selection considered proximity to the target population, the size of the population to be sampled and the sensitivity of the sampling site.

Results: One hundred and fifty three sites have been established in Africa since 2011. In 2011, Nigeria was first country to introduce environmental surveillance and currently with of 59 validated sites, followed by Kenya in 2013 validating and sampling 9 sites and Angola 4 active sites in 2014. In 2014, Cameroon introduced ES and 31 sites followed by Niger with 9 sites and Madagascar with 23 sites. Later in the same year, Chad introduced ES activity and 4 active sites were selected. In 2015 Senegal introduced 3 sites, Guinea and Burkina Faso introduced 4 sites each., and. In 2016, a total of 179 Sabins, 36 Sabin 2s, 196 non polio enteroviruses (NPEV) and 1 vaccine-derived polioviruses (VDPV) were reported in Nigeria. Cameroon and Chad isolated 14 and 4 Sabins and 72 and 40 NPEV respectively. In Madagascar a total of 39 Sabins, 11 Sabin 2s and 277 NPEV were isolated. In other countries a majority of NPEV were isolated (data not shown).

Conclusion: This report describes the progress and expansion of environmental surveillance that contributed to the identification of polioviruses from the environment and the interruption of wild poliovirus transmission in the African Region.