Pediatric Bacterial Meningitis Surveillance in the World Health Organization African Region Using the Invasive Bacterial Vaccine-Preventable Disease Surveillance Network, 2011-2016.

BACKGROUND: Bacterial meningitis is a major cause of morbidity and mortality in sub-Saharan Africa. We analyzed data from the World Health Organization's (WHO) Invasive Bacterial Vaccine-preventable Diseases Surveillance Network (2011-2016) to describe the epidemiology of laboratory-confirmed Streptococcus pneumoniae (Spn), Neisseria meningitidis, and Haemophilus influenzae meningitis within the WHO African Region. We also evaluated declines in vaccine-type pneumococcal meningitis following pneumococcal conjugate vaccine (PCV) introduction. METHODS: Reports of meningitis in children <5 years old from sentinel surveillance hospitals in 26 countries were classified as suspected, probable, or confirmed. Confirmed meningitis cases were analyzed by age group and subregion (South-East and West-Central). We described case fatality ratios (CFRs), pathogen distribution, and annual changes in serotype and serogroup, including changes in vaccine-type Spn meningitis following PCV introduction. RESULTS: Among 49 844 reported meningitis cases, 1670 (3.3%) were laboratory-confirmed. Spn (1007/1670 [60.3%]) was the most commonly detected pathogen; vaccine-type Spn meningitis cases declined over time. CFR was the highest for Spn meningitis: 12.9% (46/357) in the South-East subregion and 30.9% (89/288) in the West-Central subregion. Meningitis caused by N. meningitidis was more common in West-Central than South-East Africa (321/954 [33.6%] vs 110/716 [15.4%]; P < .0001). Haemophilus influenzae (232/1670 [13.9%]) was the least prevalent organism. CONCLUSIONS: Spn was the most common cause of pediatric bacterial meningitis in the African region even after reported cases declined following PCV introduction. Sustaining robust surveillance is essential to monitor changes in pathogen distribution and to inform and guide vaccination policies.

Pneumococcal Conjugate Vaccine Impact on Meningitis and Pneumonia Among Children Aged <5 Years-Zimbabwe, 2010-2016.

BACKGROUND: Streptococcus pneumoniae is a leading cause of pneumonia and meningitis in children aged <5 years. Zimbabwe introduced 13-valent pneumococcal conjugate vaccine (PCV13) in 2012 using a 3-dose infant schedule with no booster dose or catch-up campaign. We evaluated the impact of PCV13 on pediatric pneumonia and meningitis. METHODS: We examined annual changes in the proportion of hospitalizations due to pneumonia and meningitis among children aged <5 years at Harare Central Hospital (HCH) pre-PCV13 (January 2010-June 2012) and post-PCV13 (July 2013-December 2016) using a negative binomial regression model, adjusting for seasonality. We also evaluated post-PCV13 changes in serotype distribution among children with confirmed pneumococcal meningitis at HCH and acute respiratory infection (ARI) trends using Ministry of Health outpatient data. RESULTS: Pneumonia hospitalizations among children aged <5 years steadily declined pre-PCV13; no significant change in annual decline was observed post-PCV13. Post-PCV13 introduction, meningitis hospitalization decreased 30% annually (95% confidence interval [CI], -42, -14) among children aged 12-59 months, and no change was observed among children aged 0-11 months. Pneumococcal meningitis caused by PCV13 serotypes decreased from 100% in 2011 to 50% in 2016. Annual severe and moderate outpatient ARI decreased by 30% (95% CI, -33, -26) and 7% (95% CI, -11, -2), respectively, post-PCV13 introduction. CONCLUSIONS: We observed declines in pediatric meningitis hospitalizations, PCV13-type pneumococcal meningitis, and severe and moderate ARI outpatient visits post-PCV13 introduction. Low specificity of discharge codes, changes in referral patterns, and improvements in human immunodeficiency virus care may have contributed to the lack of additional declines in pneumonia hospitalizations post-PCV13 introduction.

Congenital Rubella Syndrome in The African Region - Data from Sentinel Surveillance.

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 Impact of Recent Rubella Vaccine Introduction in 5 Countries in The African Region.

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.

Progress Towards Measles Elimination in Nigeria: 2012 - 2016.

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.

The effect of targeted wide age range SIAs in reducing measles incidence in the African Region.

Periodic measles supplemental immunisation activities (SIAs) increase population immunity and thereby reduce the pool of accumulated susceptible children. They are typically conducted every 2 - 4 years, and most often target children up to five years of age. Between 2012 and 2015, after surveillance data indicated a shift in the epidemiological profile of measles towards older age groups, 11 countries were supported to conduct wide age range SIAs based on their local epidemiological patterns. Six other countries conducted SIAs with measles-rubella vaccines targeting ages 9 months to 14 years as an initial step of introducing rubella vaccine into the immunization program. In subsequent years, the incidence of confirmed measles dropped significantly in 13 of the 17 countries reviewed. The findings emphasize the importance of well-functioning surveillance systems, and the benefits of using of surveillance data to determine the specific target age-range for periodic SIAs to accelerate progress towards measles elimination.