Summary Background In the first 2 years after a nationwide mass vaccination campaign of 1–29-year-olds with a meningococcal serogroup A conjugate vaccine (MenAfriVac) in Burkina Faso, carriage and disease due to serogroup A Neisseria meningitidis were nearly eliminated. We aimed to assess the long-term effect of MenAfriVac vaccination on meningococcal carriage and herd immunity. Methods We did four cross-sectional studies of meningococcal carriage in people aged 9 months to 36 years in two districts of Burkina Faso between May 2, 2016, and Nov 6, 2017. Demographic information and oropharyngeal swabs were collected. Meningococcal isolates were characterised using whole-genome sequencing. Findings Of 14 295 eligible people, 13 758 consented and had specimens collected and laboratory results available, 1035 of whom were meningococcal carriers. Accounting for the complex survey design, prevalence of meningococcal carriage was 7·60% (95% CI 5·67–9·52), including 6·98% (4·86–9·11) non-groupable, 0·48% (0·01–0·95) serogroup W, 0·10% (0·01–0·18) serogroup C, 0·03% (0·00–0·80) serogroup E, and 0% serogroup A. Prevalence ranged from 5·44% (95% CI 4·18–6·69) to 9·14% (6·01–12·27) by district, from 4·67% (2·71–6·64) to 11·17% (6·75–15·59) by round, and from 3·39% (0·00–8·30) to 10·43% (8·08–12·79) by age group. By clonal complex, 822 (88%) of 934 non-groupable isolates were CC192, all 83 (100%) serogroup W isolates were CC11, and nine (69%) of 13 serogroup C isolates were CC10217. Interpretation Our results show the continued effect of MenAfriVac on serogroup A meningococcal carriage, for at least 7 years, among vaccinated and unvaccinated cohorts. Carriage prevalence of epidemic-prone serogroup C CC10217 and serogroup W CC11 was low. Continued monitoring of N meningitidis carriage will be crucial to further assess the effect of MenAfriVac and inform the vaccination strategy for future multivalent meningococcal vaccines. Funding Bill & Melinda Gates Foundation and Gavi, the Vaccine Alliance.

Background. Several studies have compared the use of dried blot spot (DBS) as an alternative to plasma specimens, mainly using Whatman 903 cards as filter paper. The aim of this study was to evaluate the use of Whatman FTA card (FTA card) specimens for HIV-1 viral load testing compared to plasma specimens using two real-time PCR assays manufactured by Roche and Abbott. Methodology. A cross-sectional study was conducted between April 2017 and September 2017 on HIV-1 patients admitted to Yalgado Ouédraogo Teaching Hospital. Paired FTA cards and plasma specimens were collected and analysed using the Abbott Real-Time HIV-1 assay (Abbott) and COBAS AmpliPrep/COBAS TaqMan v2.0 (Roche). Results. In total, 107 patients were included. No statistical differences (P>0.05) were observed between the mean viral loads obtained from the FTA cards and those of the plasma specimens using the Roche and Abbott assays. In total, 29 samples with Roche and 15 samples with Abbott assay showed discrepant results. At viral loads of ≤1000 copies ml−1, the sensitivity and specificity of the FTA cards were 78.6 and 100% with Roche, and 92.3 and 95.9% with Abbott, respectively. Both the Roche and Abbott assays showed good correlation and agreement between the FTA cards and plasma values. Conclusion. Our study demonstrates the feasibility of using FTA card filter paper for HIV-1 viral load testing. However, further studies will be required for the validation of the use of FTA card filter paper in HIV-1 treatment monitoring.

267 words 1 8 Abstract 2 3Background: Several studies have been conducted to compare the use DBS as 2 4 alternative to plasma specimens, but mainly using Whatman 903 ® cards as filter 2 5paper. The aim of this study was to evaluate Whatman FTA ® cards (FTA cards) 2 6 specimens for HIV-1 viral load testing by comparing it to plasma specimens, using 2 2 7 real-Time PCR assays. 2 8 Methodology: A cross-sectional study was conducted between April 2017 and 2 9 September 2017, in HIV-1 patients admitted at Yalgado Ouédraogo teaching 3 0 hospital. Paired FTA cards and plasma specimens were collected and analyzed 3 1 using Abbott RealTime HIV-1 assay (Abbott) and COBAS ® AmpliPrep/COBAS ® 3 2TaqMan v2.0 (Roche), following manufacturers' protocol. 3 3 Results: A total of 107 patients were included. No Statistical differences (p-value > 3 4 0.05) were observed between the mean viral loads obtained from FTA cards and 3 5 plasma specimens with Roche and Abbott assays. Twenty-nine samples with Roche 3 6 and 15 samples with Abbott assay showed discrepant results. At viral loads of ≤ 1000 3 7 copies/mL, the sensitivity and specificity of FTA cards were 78.6%, and 100% with 3 8 Roche, and 92.3% and 95.9% with Abbott. Strong correlation was found between 3 9 FTA cards and plasma specimens with both assays. With Roche, Bland-Altman 4 0 analysis showed bias of -0.3 and 95% limits of agreement of -2.6 to 1.8 log10, with 4 1 97/99 cases (97.9%) within agreement limits. With Abbott, Bland-Altman analysis 4 2showed bias of -0.1 and 95% limits of agreement of -2.3 to 2.1 log10, with 96/99 4 3 cases (96.9%) within agreement limits. 4Conclusion: Our study demonstrated the feasibility of using FTA cards filter paper 4 5