Critical success factors for high routine immunization performance: A case study of Senegal.

Background: The essential components of a vaccine delivery system are well-documented, but robust evidence is lacking on how policies and implementation strategies are operationalized to drive catalytic improvements in coverage. To address this gap, we identified success factors that supported improvements in routine immunization coverage in Senegal, especially from 2000 to 2019. Methods: We identified Senegal as an exemplar in the delivery of childhood vaccines through analysis of DTP1 and DTP3 coverage data. Through interviews and focus group discussions at the national, regional, district, health facility, and community-level, we investigated factors that contributed to high and sustained vaccination coverage. We conducted a thematic analysis through application of implementation science frameworks to determine critical success factors. We triangulated these findings with quantitative analyses using publicly available data. Results: The following success factors emerged: 1) Strong political will and prioritization of resources for immunization programming supported urgent allocation of funding and supplies; 2) Collaboration between the Ministry of Health and Social Action and external partners fostered innovation, capacity building, and efficiency; 3) Improved surveillance, monitoring, and evaluation allowed for timely and evidence-based decision making; 4) Community ownership of vaccine service delivery supported tailored programming and response to local needs; and 5) Community health workers spearheaded vaccine promotion and demand generation for vaccines. Conclusion: The vaccination program in Senegal was supported by evidence-based decision making at the national-level, alignment of priorities between governmental entities and external partners, and strong community engagement initiatives that fostered local ownership of vaccine delivery and uptake. High routine immunization coverage was likely driven by prioritization of immunization programming, improved surveillance systems, a mature and reliable community health worker program, and tailored strategies for addressing geographical, social, and cultural barriers.

Addressing disruptions in childhood routine immunisation services during the COVID-19 pandemic: perspectives and lessons learned from Liberia, Nepal, and Senegal

The COVID-19 pandemic has inflicted multifaceted disruptions to routine immunisation from global to local levels, affecting every aspect of vaccine supply, access, and demand. Since March 2020, country programmes have implemented a range of strategies to either continue vaccination services during COVID-19 measures like lockdown and/or resume services when risks of SARS-CoV-2 transmission could be appropriately mitigated. Through the Exemplars in Global Health partnership in Liberia, Nepal, and Senegal, we conducted interviews with immunisation programme managers and ministry of health leadership to better understand how they have addressed the myriad vaccination challenges posed by the ongoing pandemic. From establishing alternative modes of service delivery to combatting vaccine distrust and rumours via risk communication campaigns, many routine immunisation programmes have demonstrated how to adapt, resume, and/or maintain vital vaccination efforts during the COVID-19 crisis. Yet millions of children remain un- or under-vaccinated worldwide, and the same programmes striving to implement catch-up services for missed doses and postponed mass campaigns will also soon be tasked with COVID-19 vaccine deployment. As laid bare by the current pandemic, the worlds gains against vaccine-preventable diseases are fragile: enshrined by a delicate global ecosystem of logistics, supply, and procurement, the success of routine immunisation ultimately rests upon dedicated programme staff, the resources and support available to them, and then the trust in and demand for vaccines by their recipients. Our collective lessons learned during COVID-19 offer insights in programme adaptation and resilience that, if prioritised, could strengthen equitable, sustainable vaccine delivery for all populations. Summary boxO_LIKey message 1: As the COVID-19 pandemic affected routine immunisation services worldwide, country programmes have used a range of mitigation strategies to maintain vaccine delivery and/or resume interrupted programming. Interviews with immunisation programme managers and Ministry of Health staff provided key perspectives and lessons learned on how countries have approached routine immunisation services during the COVID-19 crisis. C_LIO_LIKey message 2: Key themes for mitigating COVID-19s effects on routine immunisation included prioritising continued services with strengthened infection prevention control; identifying alternative locations and approaches to providing vaccine services (e.g., conducting door-to-door vaccination if facility-based services were not possible); engaging in effective communications and mobilisation activities, especially to offset misinformation about COVID-19 and vaccines; setting up systems and strategies for reaching children who missed doses amid periods of disruption; and conducting catch-up campaigns as soon as SARS-CoV-2 transmission risks could be minimised. C_LIO_LIKey message 3: The ways in which COVID-19 has affected routine immunisation services have varied over time and across settings, underscoring the importance of contextually-tailored mitigation efforts and adaptation given evolving challenges amid an ongoing pandemic. As countries prepare and initiate roll-out COVID-19 vaccines, it will be vital to avoid one-size-fits-all implementation strategies and support the continuance of routine immunisation services through this next phase of COVID-19 response. C_LI

Implementation of an in-house real-time reverse transcription-PCR assay for the rapid detection of the SARS-CoV-2 Marseille-4 variant

IntroductionThe SARS-CoV-2 pandemic has been associated with the occurrence since summer 2020 of several viral variants that overlapped or succeeded each other in time. Those of current concern harbor mutations within the spike receptor binding domain (RBD) that may be associated with viral escape to immune responses. In our geographical area a viral variant we named Marseille-4 harbors a S477N substitution in this RBD. Materials and methodsWe aimed to implement an in-house one-step real-time reverse transcription-PCR (qPCR) assay with a hydrolysis probe that specifically detects the SARS-CoV-2 Marseille-4 variant. ResultsAll 6 cDNA samples from Marseille-4 variant strains identified in our institute by genome next-generation sequencing (NGS) tested positive using our Marseille-4 specific qPCR, whereas all 32 cDNA samples from other variants tested negative. In addition, 39/42 (93%) respiratory samples identified by NGS as containing a Marseille-4 variant strain and 0/26 samples identified as containing non-Marseille-4 variant strains were positive. Finally, 1,585/2,889 patients SARS-CoV-2-diagnosed in our institute, 10/277 (3.6%) respiratory samples collected in Algeria, and none of 207 respiratory samples collected in Senegal, Morocco, or Lebanon tested positive using our Marseille-4 specific qPCR. DiscussionOur in-house qPCR system was found reliable to detect specifically the Marseille-4 variant and allowed estimating it is involved in more than half of our SARS-CoV-2 diagnoses since December 2020. Such approach allows the real-time surveillance of SARS-CoV-2 variants, which is warranted to monitor and assess their epidemiological and clinical characterics based on comprehensive sets of data.

Introduction into the Marseille geographical area of a mild SARS-CoV-2 variant originating from sub-Saharan Africa

BACKGROUNDIn Marseille, France, the COVID-19 incidence evolved unusually with several successive epidemic episodes. The second outbreak started in July, was associated with North Africa, and involved travelers and an outbreak on passenger ships. This suggested the involvement of a new viral variant. METHODSWe sequenced the genomes from 916 SARS-CoV-2 strains from COVID-19 patients in our institute. The patients demographic and clinical features were compared according to the infecting viral variant. RESULTSFrom June 26th to August 14th, we identified a new viral variant (Marseille-1). Based on genome sequences (n=89) or specific qPCR (n=53), 142 patients infected with this variant were detected. It is characterized by a combination of 10 mutations located in the nsp2, nsp3, nsp12, S, ORF3a, ORF8 and N/ORF14 genes. We identified Senegal and Gambia, where the virus had been transferred from China and Europe in February-April as the sources of the Marseille-1 variant, which then most likely reached Marseille through Maghreb when French borders reopened. In France, this variant apparently remained almost limited to Marseille. In addition, it was significantly associated with a milder disease compared to clade 20A ancestor strains. CONCLUSIONOur results demonstrate that SARS-CoV-2 can genetically diversify rapidly, its variants can diffuse internationally and cause successive outbreaks.

The projected impact of mitigation and suppression strategies on the COVID-19 epidemic in Senegal: A modelling study

BackgroundPhysical distancing measures that reduce social contacts have formed a key part of national COVID-19 containment and mitigation strategies. Many Sub-Saharan African nations are now facing increasing numbers of cases of COVID-19 and there is a need to understand what levels of measures may be required to successfully reduce transmission. MethodsWe collated epidemiological data along with information on key COVID-19 specific response policies and health system capacity estimates for services needed to treat COVID-19 patients in Senegal. We calibrated an age-structured SEIR model to these data to capture transmission dynamics accounting for demography, contact patterns, hospital capacity and disease severity. We simulated the impact of mitigation and suppression strategies focussed on reducing social contact rates. ResultsSenegal acted promptly to contain the spread of SARS-CoV-2 and as a result has reduced the reproduction number from 1.9 (95% CI 1.7-2.2) to 1.3 (95% CI 1.2-1.5), which has slowed but not fully interrupted transmission. We estimate that continued spread is likely to peak in October, and to overwhelm the healthcare system with an estimated 77,400 deaths (95% CI 55,270-100,700). Further reductions in contact rates to suppress transmission (Rt<1) could significantly reduce this burden on healthcare services and improve overall health outcomes. ConclusionsOur results demonstrate that Senegal has already significantly reduced transmission. Enhanced physical distancing measures and rapid scale up of hospital capacity is likely to be needed to reduce mortality and protect healthcare infrastructure from high levels of demand.

HIV DNA and immune alteration during successful HAART.

BACKGROUND: Highly Active Antiretroviral therapy (HAART) can effectively reduce the viral load to undetectable levels in most HIV-infected patients. However, some patients may still experience impaired immunologic response associated with increased risk of disease progression and death. OBJECTIVE: The objective of this study was to assess the impact of the HIV DNA load on the immune alteration during successful HAART. METHODS: 40 chronic HIV-infected adults initiating HAART were followed for 24 months. The CD4 count, HIV viral load, HIV DNA load, and levels of γ-cytokines IL-2, IL-7 and IL-21 were monitored at baseline (month 0), month 6, 12, 18 and 24 following HAART initiation. RESULTS: The plasma viral load decreased significantly and remained below the detection limits after six months treatment. Likely the HIV DNA load decreased significantly in both cells during 12 months, was undetectable in CD14 monocytes after 18 months, but remained higher in CD3+ T cells during all the follow up. In addition, the HIV DNA load correlated positively between T cells and monocytes in 10 patients who maintained higher HIV DNA load in both cells during 12 months. The CD4 count, IL-2, and IL-21 levels increased significantly during 12 months, whereas IL-7 decreased significantly during 18 months, regardless of the HIV DNA load in T cells. Patients with CD4 count below 200/µl maintained higher HIV DNA load and showed lower increase in CD4 count compared to patients with CD4 count above 200/µl. In patients showing undetectable HIV DNA load in both cells, neither IL-2 nor IL-21 correlated with the CD4 count even after 24 months despite their partial restoration. CONCLUSION: These results suggest that the HIV DNA load could continuously hamper the CD4 restoration and γ-cytokines functional activities during HAART. This action seemed to be more severe in patients with pre-HAART CD4 count below 200/µl. The CD14 monocytes may contribute to this action as source of T cell infection both before and during HAART.