Antecedent causes of a measles resurgence in the Democratic Republic of the Congo.

INTRODUCTION: Despite accelerated measles control efforts, a massive measles resurgence occurred in the Democratic Republic of the Congo (DRC) starting in mid-2010, prompting an investigation into likely causes. METHODS: We conducted a descriptive epidemiological analysis using measles immunization and surveillance data to understand the causes of the measles resurgence and to develop recommendations for elimination efforts in DRC. RESULTS: During 2004-2012, performance indicator targets for case-based surveillance and routine measles vaccination were not met. Estimated coverage with the routine first dose of measles-containing vaccine (MCV1) increased from 57% to 73%. Phased supplementary immunization activities (SIAs) were conducted starting in 2002, in some cases with sub-optimal coverage (≤95%). In 2010, SIAs in five of 11 provinces were not implemented as planned, resulting in a prolonged interval between SIAs, and a missed birth cohort in one province. During July 1, 2010-December 30, 2012, high measles attack rates (>100 cases per 100,000 population) occurred in provinces that had estimated MCV1 coverage lower than the national estimate and did not implement planned 2010 SIAs. The majority of confirmed case-patients were aged <10 years (87%) and unvaccinated or with unknown vaccination status (75%). Surveillance detected two genotype B3 and one genotype B2 measles virus strains that were previously identified in the region. CONCLUSION: The resurgence was likely caused by an accumulation of unvaccinated, measles-susceptible children due to low MCV1 coverage and suboptimal SIA implementation. To achieve the regional goal of measles elimination by 2020, efforts are needed in DRC to improve case-based surveillance and increase two-dose measles vaccination coverage through routine services and SIAs.

Improved acute flaccid paralysis surveillance performance in the Democratic Republic of the Congo, 2010-2012.

BACKGROUND: The Democratic Republic of the Congo (DRC) began polio eradication activities in 1996. By 2001, DRC was no longer polio endemic. However, wild poliovirus (WPV) transmission was reestablished in 2006 continuing through 2011 (last WPV case onset 20 December 2011), and vaccine-derived poliovirus type 2 (VDPV2) outbreaks occurred during 2004-2012 (last VDPV2 case onset 4 April 2012). Gaps in acute flaccid paralysis (AFP) surveillance have been consistently documented. METHODS: AFP surveillance indicators were assessed at the national, provincial, and zone de santé (ZS) levels for 2010-2012. A spatiotemporal analysis of compatible, WPV type 1 (WPV1), and VDPV2 cases was performed. RESULTS: During 2010-2012, AFP cases were reported from all provinces but not every ZS, particularly in Equateur province and Province Orientale. A spatiotemporal relationship between compatible, WPV1, and VDPV2 cases was noted. Nonpolio AFP rates met objectives at national and provincial levels but were sub-optimal in certain ZS. National and provincial trends in timely stool collection, stool condition, adequate stool, and 60-day follow-up exams improved. CONCLUSIONS: DRC's AFP surveillance system is functional and improved during 2010-2012. Maintaining improvements and strengthening AFP case detection at the ZS level will provide further support for the apparent interruption of WPV and VDPV2 transmission.

Factors contributing to outbreaks of wild poliovirus type 1 infection involving persons aged ≥15 years in the Democratic Republic of the Congo, 2010-2011, informed by a pre-outbreak poliovirus immunity assessment.

BACKGROUND: The Democratic Republic of the Congo (DRC) experienced atypical outbreaks of wild poliovirus type 1 (WPV1) infection during 2010-2011 in that they affected persons aged ≥15 years in 4 (Bandundu, Bas Congo, Kasaï Occidental, and Kinshasa provinces) of the 6 provinces with outbreaks. METHODS: Analyses of cases of WPV1 infection with onset during 2010-2011 by province, age, polio vaccination status, and sex were conducted. The prevalence of antibodies to poliovirus (PV) types 1, 2, and 3 was assessed in sera collected before the outbreaks from women attending antenatal clinics in 3 of the 4 above-mentioned provinces. RESULTS: Of 193 cases of WPV1 infection during 2010-2011, 32 (17%) occurred in individuals aged ≥15 years. Of these 32 cases, 31 (97%) occurred in individuals aged 16-29 years; 9 (28%) were notified in Bandundu, 17 (53%) were notified in Kinshasa, and 22 (69%) had an unknown polio vaccination status. In the seroprevalence assessment, PV type 1 and 3 seroprevalence was lower among women aged 15-29 years in Bandundu and Kinshasa, compared with those in Kasaï Occidental. Seropositivity to PVs was associated with increasing age, more pregnancies, and a younger age at first pregnancy. CONCLUSIONS: This spatiotemporal analysis strongly suggests that the 2010-2011 outbreaks of WPV1 infection affecting young adults were caused by a PV type 1 immunity gap in Kinshasa and Bandundu due to insufficient exposure to PV type 1 through natural infection or vaccination. Poliovirus immunity gaps in this age group likely persist in DRC.

[Incidence of rubella in 2010-2012 in Kinshasa, Democratic Republic of Congo: data from the measles case-based surveillance system]. / Fréquence de la rubéole a Kinshasa de 2010 a 2012, République Démocratique du Congo (RDC): données issues du système de surveillance de la rougeole.

INTRODUCTION: No surveillance system or survey data on the congenital rubella syndrome are available in the Democratic Republic of Congo. This article describes the incidence of primary rubella infection between 2010 and 2012 based on the measles case-based surveillance system in Kinshasa. METHODS: Suspected cases of measles notified in Kinshasa between 2010 and 2012 were retrospectively analyzed. RESULTS: From January 2010 to December 2012, 1,892 suspected cases of measles were reported, and 1013 serum samples were collected according to the surveillance standard and analyzed in the laboratory. There were more cases of confirmed rubella than measles among the investigated cases. The proportion of confirmed cases of rubella has increased significantly over the last 3 years. The proportion of affected individuals of childbearing age was 15.4%, with a female predominance in this age-group. CONCLUSION: The Democratic Republic of Congo should consider revising the definition of cases used in the measles surveillance system in order to take into account the incidence of measle, establish sentinel sites for surveillance of CRS and use measles eradication activities and other mass activities to introduce rubella vaccination.

Whom and where are we not vaccinating? Coverage after the introduction of a new conjugate vaccine against group A meningococcus in Niger in 2010.

MenAfriVac is a new conjugate vaccine against Neisseria meningitidis serogroup A developed for the African "meningitis belt". In Niger, the first two phases of the MenAfriVac introduction campaign were conducted targeting 3,135,942 individuals aged 1 to 29 years in the regions of Tillabéri, Niamey, and Dosso, in September and December 2010. We evaluated the campaign and determined which sub-populations or areas had low levels of vaccination coverage in the regions of Tillabéri and Niamey. After Phase I, conducted in the Filingué district, we estimated coverage using a 30×15 cluster-sampling survey and nested lot quality assurance (LQA) analysis in the clustered samples to identify which subpopulations (defined by age 1-14/15-29 and sex) had unacceptable vaccination coverage (<70%). After Phase II, we used Clustered Lot Quality Assurance Sampling (CLQAS) to assess if any of eight districts in Niamey and Tillabéri had unacceptable vaccination coverage (<75%) and estimated overall coverage. Estimated vaccination coverage was 77.4% (95%CI: 84.6-70.2) as documented by vaccination cards and 85.5% (95% CI: 79.7-91.2) considering verbal history of vaccination for Phase I; 81.5% (95%CI: 86.1-77.0) by card and 93.4% (95% CI: 91.0-95.9) by verbal history for Phase II. Based on vaccination cards, in Filingué, we identified both the male and female adult (age 15-29) subpopulations as not reaching 70% coverage; and we identified three (one in Tillabéri and two in Niamey) out of eight districts as not reaching 75% coverage confirmed by card. Combined use of LQA and cluster sampling was useful to estimate vaccination coverage and to identify pockets with unacceptable levels of coverage (adult population and three districts). Although overall vaccination coverage was satisfactory, we recommend continuing vaccination in the areas or sub-populations with low coverage and reinforcing the social mobilization of the adult population.