Identification of transmission chains and clusters associated with COVID-19 in Tunisia

Safer, Mouna; Letaief, Hejer; Hechaichi, Aicha; Harizi, Chahida; Dhaouadi, Sonia; Bouabid, Leila; Darouiche, Sondes; Gharbi, Donia; Elmili, Nawel; Salah, Hamida Ben; Hammami, Mongi; Talmoudi, Khouloud; Moussa, Rim; Charaa, Nejib; Termiz, Hasna; Ltaief, Fethi; Tounekti, Habib; Makhlouf, Mohamed; Sriha, Asma Belguith; Fredj, Manel Ben; Khalfallah, Sonia; Jabrane, Houcine; Mchirgui, Selma; Amich, Chedli; Dabghi, Radhia; Anez, Zid; Abdelkader, Latifa; Mhamdi, Moncef; Ouerfeli, Nabil; Zoghlami, Salah; Bougatef, Souha; Chahed, Mohamed Kouni; Alaya, Nissaf Bouafif Ben

doi:10.1186/s12879-021-06107-6

Cited by 6 publications

(6 citation statements)

References 17 publications

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“…Our results also provide a demonstration of the superiority of RNA vaccines for the induction of a specific immune response over Adenovirus-based vaccines, i.e., inactivated vaccines providing less favorable results. Such data correlate well with the efficiencies found in clinical trials and real-life studies [ 3 ]. Interestingly, vaccines of the same platform gave very similar results; the only exception being the AstraZeneca and Sputnik V vaccines.…”

Section: Discussionsupporting

confidence: 82%

“…Tunisia rapidly put in place a plan to fight this threat [ 2 ]. The first case was notified on 3 March 2020 and since then the epidemic has continued to spread throughout the country [ 3 ]. Around the world, several pharmaceutical companies have started research with the aim of manufacturing a vaccine that would help to slow the momentum of the epidemic.…”

Section: Introductionmentioning

confidence: 99%

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Humoral and Cellular Immunogenicity of Six Different Vaccines against SARS-CoV-2 in Adults: A Comparative Study in Tunisia (North Africa)

et al. 2022

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Background: The mass vaccination campaign against SARS-CoV-2 was started in Tunisia on 13 March 2021 by using progressively seven different vaccines approved for emergency use. Herein, we aimed to evaluate the humoral and cellular immunity in subjects aged 40 years and over who received one of the following two-dose regimen vaccines against SARS-CoV-2, namely mRNA-1273 or Spikevax (Moderna), BNT162B2 or Comirnaty (Pfizer-BioNTech), Gam-COVID-Vac or Sputnik V (Gamaleya Research Institute), ChAdOx1-S or Vaxzevria (AstraZeneca), BIBP (Sinopharm), and Coronavac (Sinovac). Material and methods: For each type of vaccine, a sample of subjects aged 40 and over was randomly selected from the national platform for monitoring COVID-19 vaccination and contacted to participate to this study. All consenting participants were sampled for peripheral blood at 3–7 weeks after the second vaccine dose to perform anti-S and anti-N serology by the Elecsys® (Lenexa, KS, USA) anti-SARS-CoV-2 assays (Roche® Basel, Switzerland). The CD4 and CD8 T cell responses were evaluated by the QuantiFERON® SARS-CoV-2 (Qiagen® Basel, Switzerland) for a randomly selected sub-group. Results: A total of 501 people consented to the study and, of them, 133 were included for the cellular response investigations. Both humoral and cellular immune responses against SARS-CoV-2 antigens differed significantly between all tested groups. RNA vaccines induced the highest levels of humoral and cellular anti-S responses followed by adenovirus vaccines and then by inactivated vaccines. Vaccines from the same platform induced similar levels of specific anti-S immune responses except in the case of the Sputnik V and the AstraZeneca vaccine, which exhibited contrasting effects on humoral and cellular responses. When analyses were performed in subjects with negative anti-N antibodies, results were similar to those obtained within the total cohort, except for the Moderna vaccine, which gave a better cellular immune response than the Pfizer vaccine and RNA vaccines, which induced similar cellular immune responses to those of adenovirus vaccines. Conclusion: Collectively, our data confirmed the superiority of the RNA-based COVID-19 vaccines, in particular that of Moderna, for both humoral and cellular immunogenicity. Our results comparing between different vaccine platforms in a similar population are of great importance since they may help decision makers to adopt the best strategy for further national vaccination programs.

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Section: Discussionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Humoral and Cellular Immunogenicity of Six Different Vaccines against SARS-CoV-2 in Adults: A Comparative Study in Tunisia (North Africa)

et al. 2022

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“…The high number of clusters observed could be explained by active contact tracing and patient follow-up during this period. In addition, the study period for contact tracing, which was 15 months in Senegal, was longer than the studies conducted in several countries like in China 6 , 1 month, and in Tunisia, 2 months 7 .…”

Section: Discussionmentioning

confidence: 91%

Analysis of contact tracing data showed contribution of asymptomatic and non-severe infections to the maintenance of SARS-CoV-2 transmission in Senegal

Diarra

Ndiaye

Barry

et al. 2023

Sci Rep

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During the COVID-19 pandemic in Senegal, contact tracing was done to identify transmission clusters, their analysis allowed to understand their dynamics and evolution. In this study, we used information from the surveillance data and phone interviews to construct, represent and analyze COVID-19 transmission clusters from March 2, 2020, to May 31, 2021. In total, 114,040 samples were tested and 2153 transmission clusters identified. A maximum of 7 generations of secondary infections were noted. Clusters had an average of 29.58 members and 7.63 infected among them; their average duration was 27.95 days. Most of the clusters (77.3%) are concentrated in Dakar, capital city of Senegal. The 29 cases identified as super-spreaders, i.e., the indexes that had the most positive contacts, showed few symptoms or were asymptomatic. Deepest transmission clusters are those with the highest percentage of asymptomatic members. The correlation between proportion of asymptomatic and degree of transmission clusters showed that asymptomatic strongly contributed to the continuity of transmission within clusters. During this pandemic, all the efforts towards epidemiological investigations, active case-contact detection, allowed to identify in a short delay growing clusters and help response teams to mitigate the spread of the disease.

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“…The United Arab Emirates implemented a comprehensive strategy focusing on mass testing, contact tracing and isolating positive cases. Early adoption of this strategy in April 2020 contributed to a lower-than-expected mortality rate [ 103 ] • Middle-income countries (Lebanon, Jordan and Tunisia) faced challenges due to limited capacity in detecting, tracing and isolating COVID-19 cases [ 45 , 105 , 106 ]. Factors such as under-resourced surveillance systems, delayed diagnostic scale-up, inadequate isolation facilities and the absence of digital contact tracing contributed to underestimation of community spread and hindered informed decision-making.…”

Section: Resultsmentioning

confidence: 99%

Multi-sectoral collaborations in selected countries of the Eastern Mediterranean region: assessment, enablers and missed opportunities from the COVID-19 pandemic response

El-Jardali,

Fadlallah,

Daher

2024

Health Res Policy Sys

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Background The coronavirus disease 2019 (COVID-19) pandemic has emphasized the importance of multi-sectoral collaboration to respond effectively to public health emergencies. This study aims to generate evidence on the extent to which multi-sectoral collaborations have been employed in the macro-level responses to the COVID-19 pandemic in nine selected countries of the Eastern Mediterranean region (EMR). Methods The study employed in-depth analytical research design and was conducted in two phases. In the first phase, data were collected using a comprehensive documentation review. In the second phase, key informant interviews were conducted to validate findings from the first phase and gain additional insights into key barriers and facilitators. We analysed the macro-level pandemic responses across the following seven components of the analytical framework for multi-sectoral collaborations: (1) context and trigger; (2) leadership, institutional mechanisms and processes; (3) actors; (4) administration, funding and evaluation; (5) degree of multi-sectoral engagement; (6) impact; and (7) enabling factors. Results Governments in the EMR have responded differently to the pandemic, with variations in reaction speed and strictness of implementation. While inter-ministerial committees were identified as the primary mechanism through which multi-sectoral action was established and implemented in the selected countries, there was a lack of clarity on how they functioned, particularly regarding the closeness of the cooperation and the working methods. Coordination structures lacked a clear mandate, joint costed action plan, sufficient resources and regular reporting on commitments. Furthermore, there was no evidence of robust communication planning both internally, focused on promoting internal consensual decision-making and managing power dynamics, and externally, concerning communication with the public. Across the selected countries, there was strong representation of different ministries in the pandemic response. Conversely, the contribution of non-state actors, including non-governmental organizations, civil society organizations, the private sector, the media and citizens, was relatively modest. Their involvement was more ad hoc, fragmented and largely self-initiated, particularly within the selected middle- and low income- countries of the EMR. Moreover, none of the countries incorporated explicit accountability framework or included anti-corruption and counter-fraud measures as integral components of their multi-sectoral plans and coordination mechanisms. Key enablers for the adoption of multi-sectoral collaborations have been identified, paving the way for more efficient responses in the future. Discussion Mirroring global efforts, this study demonstrates that the selected countries in the EMR are making efforts to integrate multi-sectoral action into their pandemic responses. Nevertheless, persistent challenges and gaps remain, presenting untapped opportunities that governments can leverage to enhance the efficiency of future public health emergency responses.

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Identification of transmission chains and clusters associated with COVID-19 in Tunisia

Cited by 6 publications

References 17 publications

Humoral and Cellular Immunogenicity of Six Different Vaccines against SARS-CoV-2 in Adults: A Comparative Study in Tunisia (North Africa)

Humoral and Cellular Immunogenicity of Six Different Vaccines against SARS-CoV-2 in Adults: A Comparative Study in Tunisia (North Africa)

Analysis of contact tracing data showed contribution of asymptomatic and non-severe infections to the maintenance of SARS-CoV-2 transmission in Senegal

Multi-sectoral collaborations in selected countries of the Eastern Mediterranean region: assessment, enablers and missed opportunities from the COVID-19 pandemic response

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