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Touil N, Touzani CD, Benaissa EM, Kasouati J, Rhazzar Z, El Annaz H, El Mrimar N, Neffah L, Abi R, Tagajdid R, El Kochri S, Ducatez M, Akhouad Y, Reggad A, El Kassimi Z, Zrara A, Bssaibis F, El Fahime E, Amine IL, Belmekki A, Malik YS, Elouennass M, Ennibi K. Neutralising antibodies against SARS-CoV-2 give important information on Covid-19 epidemic evolution in Rabat, Morocco, March 2020-February 2021. Afr Health Sci 2023; 23:400-405. [PMID: 38357173 PMCID: PMC10862607 DOI: 10.4314/ahs.v23i3.46] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
Background The SARS-CoV-2 is an extremely contagious and acute viral disease mainly affecting humans. Objective To estimate seroprevalence of SARS-CoV-2 neutralizing antibodies (NAbs) for illegible armed force individuals living in Rabat, Morocco. Method A convenience sample (N = 2662) was conducted from May 2020 to February 2021. We used the standard neutralization assay to quantify the NAbs titers. A serum was positive when the titer was 1:4. High positive NAbs titers were defined when ≥ 1:32. Results Demographic and socioeconomic status did not affect seroprevalence data. An overall seroprevalence of 24,9% was found. Sera from blood donors, young recruits and auto-immune population had lower NAbs titers. However, titers were above 1:16 in 9% of the population with high risk of SARS-CoV-2 exposure. Seropositivity increased over time with values reaching peaks after the epidemic waves (2.4% in May 2020; 16.2% in August 2020; 22.7% in December 2020 and 37% in February 2021). Conclusion And increase of NAbs was observed over time and correlated with the post-epidemic waves of COVID-19 in Morocco.
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Affiliation(s)
- Nadia Touil
- Unité de Culture Cellulaire, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
- Virologie Moléculaire Onco-Biologie, Faculté de Médecine et de Pharmacie, Université Mohammed V, Souissi-Rabat, Morocco
| | - Charifa Drissi Touzani
- Virologie Moléculaire Onco-Biologie, Faculté de Médecine et de Pharmacie, Université Mohammed V, Souissi-Rabat, Morocco
| | - El Mostafa Benaissa
- Equipe de Reherche en Epidemiologie Bacterienne, Faculté de Médecine et de Pharmacie, Université Mohammed V, Souissi-Rabat, Morocco
| | - Jalal Kasouati
- Laboratoire de Biostatistique, de Recherche Clinique et d'Epidémiologie Faculté de Médecine et de Pharmacie, Université Mohammed V, Souissi-Rabat, Morocco
| | - Zineb Rhazzar
- Unité de Culture Cellulaire, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | - Hicham El Annaz
- Unité de Culture Cellulaire, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | - Nadia El Mrimar
- Unité de Culture Cellulaire, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | - Lamiae Neffah
- Centre de Transfusion Sanguine, Hôpital Militaire d'Instruction Mohammed V de Rabat, Rabat, Morocco
| | - Rachid Abi
- Service de Virologie, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | - Rida Tagajdid
- Service de Virologie, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | - Safae El Kochri
- Service de Virologie, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | | | - Youssouf Akhouad
- Service de Virologie, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | - Ahmed Reggad
- Service de Virologie, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | - Zouhour El Kassimi
- Service de Virologie, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | | | - Fatna Bssaibis
- Equipe de Reherche en Epidemiologie Bacterienne, Faculté de Médecine et de Pharmacie, Université Mohammed V, Souissi-Rabat, Morocco
| | | | - Idriss Lahlou Amine
- Service de Virologie, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
| | - Abdelkader Belmekki
- Centre de Transfusion Sanguine, Hôpital Militaire d'Instruction Mohammed V de Rabat, Rabat, Morocco
| | - Yashpal Singh Malik
- College of Animal Biotechnology, Guru Angad Dev Veterinary and Animal Science University (GADVASU), Punjab, India
| | - Mostafa Elouennass
- Equipe de Reherche en Epidemiologie Bacterienne, Faculté de Médecine et de Pharmacie, Université Mohammed V, Souissi-Rabat, Morocco
| | - Khalid Ennibi
- Unité de Culture Cellulaire, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
- Service de Virologie, Centre des Maldies Infectieuses et Tropicales, Hôpital Militaire d'Instruction Mohammed V de Rabat, Morocco
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Standl F, Kowall B, Frost AK, Brune B, Brinkmann M, Dudda M, Oesterling F, Jansen P, Jöckel KH, Stang A. Calculating the number of undetected active SARS-CoV-2 infections from results of population-wide antigen tests. J Med Life 2021; 14:797-801. [PMID: 35126750 PMCID: PMC8811667 DOI: 10.25122/jml-2021-0243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/26/2021] [Indexed: 11/17/2022] Open
Abstract
Current European research estimates the number of undetected active SARS-CoV-2 infections (dark figure) to be two- to 130-fold the number of detected cases. We revisited the population-wide antigen tests in Slovakia and South Tyrol and calculated the dark figure of active cases in the vulnerable populations and the number of undetected active cases per detected active case at the time of the population-wide tests. Our analysis follows three steps: using the sensitivities and specificities of the used antigen tests, we first calculated the number of test-positive individuals and the proportion of actual positives in those who participated in the antigen tests. We then calculated the dark figure in the total population of Slovakia and South Tyrol, respectively. Finally, we calculated the ratio of the dark figure in the vulnerable population to the number of newly detected infections through PCR tests. Per one positive PCR result, another 0.15 to 0.71 cases must be added in South Tyrol and 0.01 to 1.25 cases in Slovakia. The dark figure was in both countries lower than assumed by earlier studies.
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Affiliation(s)
- Fabian Standl
- Institute for Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany,Corresponding Author: Fabian Standl, Institute for Medical Informatics, Biometry and Epidemiology (IMIBE), University Hospital Essen Hufelandstr, 55D-45147 Essen, Germany. Phone: +49 201/723-77263; E-mail:
| | - Bernd Kowall
- Institute for Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany
| | - Anna Katharina Frost
- Institute for Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany
| | - Bastian Brune
- Medical Direction Communal Emergency Service of the City Essen, Essen, Germany,Clinic for Trauma, Hand and Reconstructive Surgery, University Hospital Essen, Essen, Germany
| | - Marcus Brinkmann
- Center for Clinical Trials Essen, University Hospital Essen, Essen, Germany
| | - Marcel Dudda
- Medical Direction Communal Emergency Service of the City Essen, Essen, Germany,Clinic for Trauma, Hand and Reconstructive Surgery, University Hospital Essen, Essen, Germany
| | | | - Philipp Jansen
- Clinic for Dermatology, University Hospital Essen, Essen, Germany
| | - Karl-Heinz Jöckel
- Institute for Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany
| | - Andreas Stang
- Institute for Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany,Department of Epidemiology, Boston University, Boston, United States of America
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