Improved vaccination coverage after two rounds of multi-antigenic catch-up vaccination in Mauritania.

Although Mauritania carried out its Expanded Programme on Immunization (EPI), in 2015 the goal of vaccination coverage (VC) remained unmet in Bassikounou district and Mbera camp, contexts with large migrant populations. In response, during 2018, the national authorities, together with Médecins Sans Frontières organised two rounds of multi-antigenic mass vaccination campaigns (2RMASVC). The campaigns included oral polio (OPV), pneumococcal (PCV13), pentavalent and rotavirus vaccines for all eligible children six weeks to 59 months old. This study describes the results of the 2RMASVC. Cross-sectional household VC surveys (VCS1 and VCS2) were conducted before and after the 2RMASVC. Data were collected on vaccination status according to self-reporting and vaccination cards, and on reasons for non-vaccination (RNV). In total, 4,569 children received at least one dose of vaccine in the first round and 5,602 children in the second. Baseline VC, as fully vaccinated, according to VCS1, was 59.9% of children 12 to 59 months in Bassikounou district and 65.8% in Mbera camp. After the 2RMASVC, the coverages increased to 84.7% and 75.9% respectively. Absence from home, lack of motivation, late initiation of vaccinations and lack of awareness about vaccination were the main RNV during the 2RMASVC. Although the 2RMASVC did not reach its goal of 90%-95% VC, the strategy significantly increased VC in the two settings for children aged 12 to 59 months. Therefore, this catch-up approach could be considered to improve VC of children who miss out of the EPI strategy in resource-limited settings.

Global impact of rotavirus vaccine introduction on rotavirus hospitalisations among children under 5 years of age, 2008-16: findings from the Global Rotavirus Surveillance Network.

BACKGROUND: Rotavirus vaccine use in national immunisation programmes has led to declines in hospital admissions for rotavirus gastroenteritis among children; however, the global impact of rotavirus vaccine introduction has not been described using primary data. We describe the impact of rotavirus vaccine introduction on admissions for acute rotavirus gastroenteritis in primarily low-income and middle-income countries, using 9 years of data from the WHO-coordinated Global Rotavirus Surveillance Network (GRSN). METHODS: Between Jan 1, 2008, and Dec 31, 2016, children younger than 5 years of age who were admitted to hospital with acute gastroenteritis were prospectively enrolled in GRSN sites. We included sites that enrolled children and collected stool specimens monthly and tested at least 100 specimens annually in the impact analysis, with a separate analysis taking into account site continuity. We compared proportions of acute gastroenteritis cases positive for rotavirus in the pre-vaccine and post-vaccine periods and calculated mean proportion changes for WHO regions, with 95% CIs; these findings were then compared with interrupted time series analyses. We did further sensitivity analyses to account for rotavirus vaccination coverage levels and sites that collected specimens for at least 11 months per year and tested at least 80 specimens per year. We also analysed the age distribution of rotavirus-positive cases before and after vaccine introduction. FINDINGS: 403 140 children younger than 5 years of age admitted to hospital with acute gastroenteritis from 349 sites in 82 countries were enrolled over the study period, of whom 132 736 (32·9%) were positive for rotavirus. We included 305 789 children from 198 sites in 69 countries in the impact analysis. In countries that had not introduced rotavirus vaccine in their national immunisation programmes, rotavirus was detected in 38·0% (95% CI 4·8-73·4) of admissions for acute gastroenteritis annually whereas in those that have introduced the vaccine, rotavirus was detected in 23·0% (0·7-57·7) of admissions for acute gastroenteritis, showing a 39·6% (35·4-43·8) relative decline following introduction. Interrupted time series analyses confirmed these findings. Reductions by WHO regions ranged from 26·4% (15·0-37·8) in the Eastern Mediterranean Region to 55·2% (43·0-67·4) in the European Region and were sustained in nine countries (contributing up to 31 sites) for 6-10 years. The age distribution of children with rotavirus gastroenteritis shifted towards older children after rotavirus vaccine introduction. INTERPRETATION: A significant and sustained reduction in the proportion of hospital admissions for acute gastroenteritis due to rotavirus was seen among children younger than 5 years in GRSN sites following rotavirus vaccine introduction. These findings highlight the need to incorporate rotavirus vaccines into immunisation programmes in countries that have not yet introduced them and underline the importance of high-quality surveillance. FUNDING: The GRSN receives funding from Gavi, the Vaccine Alliance and the US Centers for Disease Control and Prevention. No specific funding was provided for this Article.

Can vaccination coverage be improved by reducing missed opportunities for vaccination? Findings from assessments in Chad and Malawi using the new WHO methodology.

BACKGROUND: In 2015, the World Health Organization (WHO) updated the global methodology for assessing and reducing missed opportunities for vaccination (MOV), when eligible children have contact with the health system but are not vaccinated. This paper presents the results of two pilot assessments conducted in Chad and Malawi. METHODS: Using the ten-step global WHO MOV strategy, we purposively selected districts and health facilities, with non-probabilistic sampling of <24 month old children for exit interviews of caregivers and self-administered knowledge, attitudes, and practices (KAP) surveys of health workers. MOV were calculated based on a child's documented vaccination history (i.e., from a home-based record (HBR) or a health facility vaccination register), including selected vaccines in the national schedule. RESULTS: Respondents included caregivers of 353 children in Chad and of 580 children in Malawi. Among those with documented vaccination history, 82% (195/238) were eligible for vaccination in Chad and 47% (225/483) in Malawi. Among eligible children, 51% (99/195) in Chad, and 66% (149/225) in Malawi had one or more MOV on the survey date. During non-vaccination visits, 77% (24/31) of children eligible for vaccination in Chad and 92% (119/129) in Malawi had a MOV compared to 46% (75/164) and 31% (30/96) during vaccination visits, respectively. Among health workers, 92% in Chad and 88% in Malawi were unable to correctly identify valid contraindications for vaccination. CONCLUSION: The new MOV tool was able to characterize the type and potential causes of MOV. In both countries, the findings of the assessments point to two major barriers to full vaccination of eligible children-a lack of coordination between vaccination and curative health services and incomplete vaccination during vaccination visits. National immunization programs should explore tailored efforts to improve health worker practices and to increase vaccine delivery by making better use of existing health service contacts.

Implementation of Rotavirus Surveillance and Vaccine Introduction - World Health Organization African Region, 2007-2016.

Rotavirus is a leading cause of severe pediatric diarrhea globally, estimated to have caused 120,000 deaths among children aged <5 years in sub-Saharan Africa in 2013 (1). In 2009, the World Health Organization (WHO) recommended rotavirus vaccination for all infants worldwide (2). Two rotavirus vaccines are currently licensed globally: the monovalent Rotarix vaccine (RV1, GlaxoSmithKline; 2-dose series) and the pentavalent RotaTeq vaccine (RV5, Merck; 3-dose series). This report describes progress of rotavirus vaccine introduction (3), coverage (using estimates from WHO and the United Nations Children's Fund [UNICEF]) (4), and impact on pediatric diarrhea hospitalizations in the WHO African Region. By December 2016, 31 (66%) of 47 countries in the WHO African Region had introduced rotavirus vaccine, including 26 that introduced RV1 and five that introduced RV5. Among these countries, rotavirus vaccination coverage (completed series) was 77%, according to WHO/UNICEF population-weighted estimates. In 12 countries with surveillance data available before and after vaccine introduction, the proportion of pediatric diarrhea hospitalizations that were rotavirus-positive declined 33%, from 39% preintroduction to 26% following rotavirus vaccine introduction. These results support introduction of rotavirus vaccine in the remaining countries in the region and continuation of rotavirus surveillance to monitor impact.

Introduction of Inactivated Poliovirus Vaccine and Trivalent Oral Polio Vaccine/Bivalent Oral Polio Vaccine Switch in the African Region.

The Polio Eradication and Endgame Strategic plan outlines the phased removal of oral polio vaccines (OPVs), starting with type 2 poliovirus-containing vaccine and introduction of inactivated polio vaccine in routine immunization to mitigate against risk of vaccine-associated paralytic polio and circulating vaccine-derived poliovirus. The objective includes strengthening routine immunization as the primary pillar to sustaining high population immunity. After 2 years without reporting any wild poliovirus (July 2014-2016), the region undertook the synchronized switch from trivalent OPV (tOPV) to bivalent OPV (bOPV) as recommended by the Strategic Advisory Group of Experts on Immunization. Consequently the 47 countries of the World Health Organization (WHO) African Region switched from the use of tOPV to bOPV within the stipulated period of April 2016. Planning started early, routine immunization was strengthened, and technical and financial support was provided for vaccine registration, procurement, destruction, logistics, and management across countries by WHO in collaboration with the United Nations Children's Fund (UNICEF) and partners. National commitment and ownership, as well as strong coordination and collaboration between UNICEF and WHO and with partners, ensured success of this major, historic public health undertaking.

Assessing the potency of oral polio vaccine kept outside of the cold chain during a national immunization campaign in Chad.

This study is the first systematic documentation of the potency of monovalent oral polio vaccine type 3 (mOPV3) kept at ambient temperatures during a polio immunization campaign in Chad. During the study test vials were exposed to temperatures of up to 47.1 °C, and kept outside of the 2-8 °C range for a maximum of 86.9 hours. Post-campaign laboratory testing confirmed that the test vials were still potent, and in conformity with the defined release specifications. Further, the Vaccine Vial Monitors performed as expected, giving an early warning indication of when cumulative exposure to heat reached levels that may have negatively affected the vaccine's potency. This study provides proof-of-concept evidence that certain types of OPV remain potent and thus can be kept, for limited periods of time, as well as administered at ambient temperatures.

[Evaluation of the lifetime of nail markings during polio vaccinations in Chad]. / Évaluation de la durée de vie des marquages sur l'ongle pendant les vaccinations polio au Tchad.

BACKGROUND: SID (Supplemental Immunization Days) is a special strategy intended to accelerate eradication of poliomyelitis in countries where it is still endemic (India, Afghanistan, and Pakistan in Asia, and Nigeria in Africa). This strategy is also applied in Nigeria's neighbours (Cameroon, Chad, Niger and Benin). Since the poliomyelitis virus was imported from Nigeria in 2001, Chad has reported cases of poliomyelitis every year. After 30 SIDs in Chad and the inaccurate or false attribution of side-effects to polio vaccines, some groups persistently refuse polio vaccination. To ascertain the true coverage of SID, the Ministry of Health and several partners (WHO, UNICEF and Rotary) conduct external coverage evaluations, to identify the under-vaccinated areas where population may be refusing immunization. The nails of the children receiving vaccinations are marked with indelible ink and those markings are the best indicator of the area's actual SID coverage. When coverage investigators arrive and propose vaccination to all children not immunized during SID, mothers who wish to refuse vaccination may claim that the children's markings disappeared after a few days, due to bathing. WHO experts have found that markings applied to their own nails with the WHO-recommended markers persist a few weeks, but others suggested that the markings may disappear much faster among children living in a traditional tropical environment. Until now, the lifetime of these markings has not been tested among children in Africa. OBJECTIVES: To determine the lifetime of the fingernail markings after SID and factors that influence this lifetime in children young than 5 years old in Chad. MATERIALS AND METHODS: This prospective cohort study of 200 children (aged 0 to 59 months) took place from March to May 2009 in Milezi, a health zone north of Ndjamena, the capital of Chad, in central Africa. These children received nail markings on their left little finger with an indelible marker pen provided by WHO. The finger was monitored for 35 days, visually and by photographs, to determine the factors associated with the lifetime of the markings. Kaplan-Meier and log-rank methods were applied to estimate their survival curve and the variables significant for their lifetime; the Cox proportional hazard model was used to determine multivariable-adjusted hazard ratios. RESULTS: Of the 184 children surveyed through the end of the study, the markings disappeared after 35 days of follow-up for 35% of them. The average lifetime of markings on these children was 28 days (SD: 4.95) and was associated, according to the Cox model, with 3 variables: the quality of the marking (RR = 0.335, 95% CI: 0.182-0.617, p < 0.001), playing with soil or mud (RR = 0.38, 95% CI: 0.208-0.697, p = 0.002), and living in different blocks, after stratification for the variable of application of chemical products on the nail. The latter could not be included in the Cox model because it made the markings disappear instantly. CONCLUSION: WHO experts were right in stating that the lifetime of the markings was sufficient to estimate coverage accurately when external evaluation takes place one or two weeks after SID. The only action found to make markings disappear rapidly was the application of chemical products. Mothers who tell SID attendance evaluation teams that the marking disappeared with bathing are expressing a tacit refusal of vaccination. These evaluations, which take place well before the disappearance of markings, help to determine the precise coverage of SID.

Crimean-Congo hemorrhagic fever, Mauritania.

From February to August 2003, 38 persons were infected with Crimean-Congo hemorrhagic fever (CCHF) virus in Mauritania; 35 of these persons were residents of Nouakchott. The first patient was a young woman who became ill shortly after butchering a goat. She transmitted the infection to 15 persons in the hospital where she was admitted and four members of her family. In Nouakchott, two disease clusters and 11 isolated cases were identified. The case-fatality ratio was 28.6%. Of the patients not infected by the first case-patient, almost half were butchers, which suggests that the primary mode of animal-to-human transmission was direct contact with blood of infected animals. The hospital outbreak alerted health authorities to sporadic cases that occurred in the following weeks, which would have probably gone otherwise unnoticed. Studies must be conducted to determine the potential risk for continued sporadic outbreaks of CCHF in humans and to propose prevention measures.