Olivier Ronveaux

Accuracy and quality of immunization information systems in forty-one low income countries

Objectives  To measure the accuracy and quality of immunization information systems in a range of low‐income countries eligible to receive GAVI support.

Benefits of using vaccines out of the cold chain: delivering meningitis A vaccine in a controlled temperature chain during the mass immunization campaign in Benin.

Highlights • The first field use of MenAfriVacs new label allowed the vaccine to be kept at up to 40 °C for up to 4 days.• 155,000 people were vaccinated using the CTC approach in the Meningitis A campaign in northern Benin in 2012.• 98.7% of supervisors and 100% of vaccinators would prefer to conduct their next campaign using CTC.• They saw CTC benefits as: more people vaccinated, no need to return to health centre every night, reduced logistic burden.• Taking advantage of the flexibility offered by CTC opens the door for the implementation of new immunization strategies.

Whole-Genome Characterization of Epidemic Neisseria meningitidis Serogroup C and Resurgence of Serogroup W, Niger, 2015

In 2015, Niger reported the largest epidemic of Neisseria meningitidis serogroup C (NmC) meningitis in sub-Saharan Africa. The NmC epidemic coincided with serogroup W (NmW) cases during the epidemic season, resulting in a total of 9,367 meningococcal cases through June 2015. To clarify the phylogenetic association, genetic evolution, and antibiotic determinants of the meningococcal strains in Niger, we sequenced the genomes of 102 isolates from this epidemic, comprising 81 NmC and 21 NmW isolates. The genomes of 82 isolates were completed, and all 102 were included in the analysis. All NmC isolates had sequence type 10217, which caused the outbreaks in Nigeria during 2013–2014 and for which a clonal complex has not yet been defined. The NmC isolates from Niger were substantially different from other NmC isolates collected globally. All NmW isolates belonged to clonal complex 11 and were closely related to the isolates causing recent outbreaks in Africa.

Emergence of epidemic Neisseria meningitidis serogroup C in Niger, 2015: an analysis of national surveillance data.

BACKGROUND To combat Neisseria meningitidis serogroup A epidemics in the meningitis belt of sub-Saharan Africa, a meningococcal serogroup A conjugate vaccine (MACV) has been progressively rolled out since 2010. We report the first meningitis epidemic in Niger since the nationwide introduction of MACV. METHODS We compiled and analysed nationwide case-based meningitis surveillance data in Niger. Cases were confirmed by culture or direct real-time PCR, or both, of cerebrospinal fluid specimens, and whole-genome sequencing was used to characterise isolates. Information on vaccination campaigns was collected by the Niger Ministry of Health and WHO. FINDINGS From Jan 1 to June 30, 2015, 9367 suspected meningitis cases and 549 deaths were reported in Niger. Among 4301 cerebrospinal fluid specimens tested, 1603 (37·3%) were positive for a bacterial pathogen, including 1147 (71·5%) that were positive for N meningitidis serogroup C (NmC). Whole-genome sequencing of 77 NmC isolates revealed the strain to be ST-10217. Although vaccination campaigns were limited in scope because of a global vaccine shortage, 1·4 million people were vaccinated from March to June, 2015. INTERPRETATION This epidemic represents the largest global NmC outbreak so far and shows the continued threat of N meningitidis in sub-Saharan Africa. The risk of further regional expansion of this novel clone highlights the need for continued strengthening of case-based surveillance. The availability of an affordable, multivalent conjugate vaccine may be important in future epidemic response. FUNDING MenAfriNet consortium, a partnership between the US Centers for Disease Control and Prevention, WHO, and Agence de Médecine Preventive, through a grant from the Bill & Melinda Gates Foundation.

Clustered lot quality assurance sampling: a pragmatic tool for timely assessment of vaccination coverage

Objectives  To evaluate oral poliovirus vaccine (OPV) coverage of the November 2009 round in five Northern Nigeria states with ongoing wild poliovirus transmission using clustered lot quality assurance sampling (CLQAS).

Clustered lot quality assurance sampling to assess immunisation coverage: increasing rapidity and maintaining precision

Objective  Vaccination programmes targeting disease elimination aim to achieve very high coverage levels (e.g. 95%). We calculated the precision of different clustered lot quality assurance sampling (LQAS) designs in computer‐simulated surveys to provide local health officers in the field with preset LQAS plans to simply and rapidly assess programmes with high coverage targets.

Using oral polio vaccine beyond the cold chain: A feasibility study conducted during the national immunization campaign in Mali

We conducted the first systematic documentation of using oral polio vaccine (OPV) out of the cold chain during national immunization day (NID) campaigns in Mali. Using a crossover intervention design, vaccinators compared the transport of OPV in vaccine carriers with or without ice packs. Vaccine integrity was assured through monitoring vaccine vial monitor (VVM) status. Despite ambient temperatures up to 40 degrees C, none of the VVMs on any of the vials used (n=956) reached their discard point. Over 90% of vaccinators and supervisors preferred conducting NIDs without ice packs. In addition, using OPV out of the cold chain reduced vaccine wastage resulting from melting ice packs causing labels to detach from the vial.

Intervene before leaving: clustered lot quality assurance sampling to monitor vaccination coverage at health district level before the end of a yellow fever and measles vaccination campaign in Sierra Leone in 2009

BackgroundIn November 2009, Sierra Leone conducted a preventive yellow fever (YF) vaccination campaign targeting individuals aged nine months and older in six health districts. The campaign was integrated with a measles follow-up campaign throughout the country targeting children aged 9–59 months. For both campaigns, the operational objective was to reach 95% of the target population. During the campaign, we used clustered lot quality assurance sampling (C-LQAS) to identify areas of low coverage to recommend timely mop-up actions.MethodsWe divided the country in 20 non-overlapping lots. Twelve lots were targeted by both vaccinations, while eight only by measles. In each lot, five clusters of ten eligible individuals were selected for each vaccine. The upper threshold (UT) was set at 90% and the lower threshold (LT) at 75%. A lot was rejected for low vaccination coverage if more than 7 unvaccinated individuals (not presenting vaccination card) were found. After the campaign, we plotted the C-LQAS results against the post-campaign coverage estimations to assess if early interventions were successful enough to increase coverage in the lots that were at the level of rejection before the end of the campaign.ResultsDuring the last two days of campaign, based on card-confirmed vaccination status, five lots out of 20 (25.0%) failed for having low measles vaccination coverage and three lots out of 12 (25.0%) for low YF coverage. In one district, estimated post-campaign vaccination coverage for both vaccines was still not significantly above the minimum acceptable level (LT = 75%) even after vaccination mop-up activities.ConclusionC-LQAS during the vaccination campaign was informative to identify areas requiring mop-up activities to reach the coverage target prior to leaving the region. The only district where mop-up activities seemed to be unsuccessful might have had logistical difficulties that should be further investigated and resolved.

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 vaccines 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.

Assessment of the quality of immunization data produced by the national individual registration system in Uruguay, 2006

OBJECTIVE The nominal registration system of Uruguays national immunization program (NIP) tracks administered vaccines on a paper form filled out after each vaccination and collated into a national database, thus allowing for individual follow-up. This study performed a comprehensive assessment of the quality of Uruguays immunization data in November 2006 to evaluate the validity of the information and to confirm the high national immunization coverage reported by the program. METHODS The research team analyzed the concordance of the operational-level numerators (infant immunization data from 18 public and private vaccination centers in six country departments) with department- and national-level data, and compared the national-level (NIP) infant denominators with other official sources. A standardized questionnaire was used to evaluate system performance at the operational (vaccination center), department, and national level. Rapid house-to-house monitoring was conducted to generate additional coverage estimates. RESULTS Numerator accuracy throughout the data flow was 100%, and national-level denominators appeared to be exhaustive. Overall system performance was excellent (proper archiving and recording of form data, sufficient supply of forms, timely flow of information, adequate defaulter tracing practices and computer system security). The main weaknesses were the degree of data analysis and feedback to peripheral levels. House-to-house monitoring showed high overall immunization coverage (97%). CONCLUSION Uruguays NIP registration system produces remarkably reliable information, ensuring valid measurement of immunization coverage. In addition, by allowing for monitoring of each childs current vaccination status, it facilitates management of interventions designed to reduce vaccination default and thus helps achieve the countrys high level of coverage.