SARS-CoV-2 infection and antibody seroprevalence in routine surveillance patients, healthcare workers and general population in Kita region, Mali: an observational study 2020–2021

Alber, Dagmar; Haidara, Fadima Cheick; Luoma, Juho; Adubra, Laura; Ashorn, Per; Ashorn, Per; Badji, Henry; Cloutman-Green, Elaine; Diallo, Fatoumata; Ihamuotila, Rikhard; Klein, Nigel; Martell, Owen; Onwuchekwa, Uma; Samaké, Oumar; Sow, Samba O.; Traoré, Awa; Wilson, Kevin R.; Ducker, Camilla; Fan, Yue‐Mei

doi:10.1136/bmjopen-2021-060367

Cited by 3 publications

(3 citation statements)

References 29 publications

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“…The infection rate among healthcare workers suggests that SARS-CoV-2 may have been more widespread than reported in the Malian population. This was confirmed in a rural study that demonstrated up to 45% seropositivity in community members over the age of 60 in the same time period [39]. Viral strains such as the one reported here, which have the capacity for rapid reproductive rates, may have contributed to the wide dissemination of the SARS-CoV-2 virus in the population.…”

Section: Discussionsupporting

confidence: 82%

Mutations in Spike Gene of SARS-CoV-2 that Are Associated with a Higher Viral Load: A Clinical Case Study

Keita¹,

Dabo²,

Doumbia³

et al. 2022

CRCM

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Background: Quantitative PCR (qPCR) can be used to detect and quantify a load of a pathogen. It is a good indicator of the degree of transmissibility. While performing routine qPCR, we observed an unusually short cycle threshold (Ct) value of SARS-CoV-2 for a clinical specimen obtained in Bamako, Mali. This prompted us to sequence the short-cycle SARS-CoV-2 sample to identify potential mutations in the Spike gene (S gene) gene. Methods: Post-infection, Quantitative Reverse Transcription (qRT-PCR) was performed over a defined time course to estimate the Ct of the SARS-CoV-2 specimen collected from the patient. Sanger sequencing was done on the entire fragment of the S gene to identify mutations. Findings: Sanger sequencing revealed mutations in the lineage of interest, designated B.1.525 by Pango, and also known as "Eta" using the nomenclature defined by WHO. This variant was originally found in Nigeria and Italy. The four novel mutations identified in Eta (D228N, Y451N, I1172M, and C1250F) were otherwise observed with a low frequency worldwide. Although the initial Ct was 10 in the case study patient, he did not exhibit severe symptoms of SARS-CoV-2, for example, pneumonia. However, we observed a longer viral clearance period than usual, of 3 weeks. We note that as compared to SARS-CoV-2 samples obtained during the first peaks of SARS-CoV-2 infection in Mali, when the

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Section: Discussionsupporting

confidence: 82%

Mutations in Spike Gene of SARS-CoV-2 that Are Associated with a Higher Viral Load: A Clinical Case Study

Keita¹,

Dabo²,

Doumbia³

et al. 2022

CRCM

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“…The comparison between study-based estimates and WHO-reported estimates are as shown in Table 3 and Figure 5. For seven of the included prevalence studies 27,[48][49][50][51][52][53] (marked with * in Table 3), WHO reported daily cumulative COVID-19 cases were not available when stratified by age group, thus all-ages prevalence was used as a comparator. Out of the 28 studies, 4 studies from England 40,43,[45][46][47] , United…”

Section: General Description Of the Studiesmentioning

confidence: 99%

Prevalence and seroprevalence of COVID-19 infection among older people: A scoping review based on population-based studies in 2020-2022

Lei,

Soe

2024

Preprint

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Background Accurate estimates of the prevalence of infections play an important role in COVID-19 surveillance. Older people are known to have higher risks of severe outcomes after infection, but whether they also have a higher infection rate remains unclear. To obtain estimates of COVID-19 prevalence among older people, we synthesized evidence from RT-PCR-based prevalence and serological studies. Methods We conducted a scoping review using a comprehensive search of MEDLINE (Ovid), Embase (Ovid), Europe PMC, ClinicalTrials.gov, and the WHO COVID-19 Research Database from December 2019 to Oct 2022. We included population-based cross-sectional (sero)prevalence studies among older people (i.e., people aged >= 65 +/- 5 years) who were tested for SARS-CoV-2 infection using RT-PCR tests, antigen tests, or serological tests. Studies that were conducted solely in institutional housing were excluded. Eligible studies were extracted and critically appraised. We described and mapped the prevalence (tested by RT-PCR or antigen tests) and seroprevalence (tested by serological tests) by geographical area and time. We then compared the estimated prevalence with WHO-reported prevalence and the prevalence among younger age groups from the same study. Results We identified 202 (sero)prevalence estimates from 126 studies, covering 50 countries up to October 2022. Of the 126 studies, 28 estimated RT-PCR-based prevalence; 104 studies estimated seroprevalence, ranging from 0% in Jordan to 22.5% in the United States in 2020, from 0.41% in Brazil to 98% in Chile in 2021. In the year 2020, the prevalence of COVID-19 ranged from 0.0006% in China to 52.8% in Brazil, while in 2021, the prevalence ranged from 0.06% in England to 41.1% in Brazil. The ratio of the reported prevalence to estimated prevalence ranged from <0.01 to 77.50, where 86% (24/28) studies estimated a higher prevalence than WHO reported, and half of them estimated >10 times higher prevalence. One-third of studies (32%, 9/28) estimated a higher prevalence in older people than younger people. Conclusions Our findings suggest that underreporting of COVID-19 cases among older people may exist extensively worldwide. Compared with younger groups, older people were less likely to be infected with COVID-19 in two-thirds of the studies through the first two years of the pandemic.

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“…These serosurveys can give an estimation of the proportion of individuals that have been exposed to SARS‐CoV‐2, providing critical data to inform decision making on control strategies such as vaccination [ 5 ]. This approach has been extensively used for SARS‐CoV‐2 globally and especially in African countries [ 3 , 8 , 9 , 10 ] where testing capacity was an issue, under the coordination of the World Health Organization (WHO), in the UNITY protocol [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

High SARS‐CoV‐2 Exposure in Rural Southern Mozambique After Four Waves of COVID‐19: Community‐Based Seroepidemiological Surveys

de Jesus,

Ernesto,

Massinga

et al. 2024

Influenza Resp Viruses

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BackgroundMozambique was one of many African countries with limited testing capacity for SARS‐CoV‐2. Serosurveys, an alternative to estimate the real exposure to understand the epidemiology and transmission dynamics, have been scarce in Mozambique. Herein, we aimed to estimate the age‐specific seroprevalence of SARS‐CoV‐2 in the general population of the Manhiça District, at four time points, for evaluating dynamics of exposure and the impact of vaccination.MethodsWe conducted four community‐based seroepidemiological surveys separated by 3 months between May 2021 and June 2022 to assess the prevalence of SARS‐CoV‐2 antibodies. An age‐stratified (0–19, 20–39, 40–59, and ≥ 60 years) sample of 4810 individuals was randomly selected from demographic surveillance database, and their blood samples were analyzed using WANTAI SARS‐CoV‐2 IgG + IgM ELISA. Nasopharyngeal swabs from a subsample of 2209 participants were also assessed for active infection by RT‐qPCR.ResultsSARS‐CoV‐2 seroprevalence increased from 27.6% in the first survey (May 2021) to 63.6%, 91.2%, and 91.1% in the second (October 2021), third (January 2022), and fourth (May 2022) surveys, respectively. Seroprevalence in individuals < 18 years, who were not eligible for vaccination, increased from 23.1% in the first survey to 87.1% in the fourth. The prevalence of active infection was below 10.1% in all surveys.ConclusionsA high seroprevalence to SARS‐CoV‐2 was observed in the study population, including individuals not eligible for vaccination at that time, particularly after circulation of the highly transmissible Delta variant. These data are important to inform decision making on the vaccination strategies in the context of pandemic slowdown in Mozambique.

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SARS-CoV-2 infection and antibody seroprevalence in routine surveillance patients, healthcare workers and general population in Kita region, Mali: an observational study 2020–2021

Cited by 3 publications

References 29 publications

Mutations in Spike Gene of SARS-CoV-2 that Are Associated with a Higher Viral Load: A Clinical Case Study

Mutations in Spike Gene of SARS-CoV-2 that Are Associated with a Higher Viral Load: A Clinical Case Study

Prevalence and seroprevalence of COVID-19 infection among older people: A scoping review based on population-based studies in 2020-2022

High SARS‐CoV‐2 Exposure in Rural Southern Mozambique After Four Waves of COVID‐19: Community‐Based Seroepidemiological Surveys

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