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SARS-CoV-2 antibody seroprevalence and associated risk factors in an urban district in Cameroon.

ABSTRACT: The extent of SARS-CoV-2 circulation in many African countries remains unclear, underlining the need for antibody sero-surveys to assess the cumulative attack rate. Here, we present the results of a cross-sectional sero-survey of a random sample of residents of a health district in Yaounde, Cameroon, conducted from October 14 to November 26, 2020. Among the 971 participants, the test-adjusted seroprevalence of anti-SARS-CoV-2 IgG antibodies was 29·2% (95% CI 24·3-34·1). This is about 322 times greater than the 0.09% nationwide attack rate implied by COVID-19 case counts at the time. Men, obese individuals and those living in large households were significantly more likely to be seropositive, and the majority (64·2% [58·7-69·4]) of seropositive individuals reported no symptoms. Despite the high seroprevalence, most of the population had not been infected with SARS-CoV-2, highlighting the importance of continued measures to control viral spread and quick vaccine deployment to protect the vulnerable.

SUBMITTER: Nwosu K

PROVIDER: S-EPMC8494753 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature

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SARS-CoV-2 antibody seroprevalence and associated risk factors in an urban district in Cameroon.

Nwosu Kene K Fokam Joseph J Wanda Franck F Mama Lucien L Orel Erol E Ray Nicolas N Meke Jeanine J Tassegning Armel A Takou Desire D Mimbe Eric E Stoll Beat B Guillebert Josselin J Comte Eric E Keiser Olivia O Ciaffi Laura L

Nature communications 20211006 1

The extent of SARS-CoV-2 circulation in many African countries remains unclear, underlining the need for antibody sero-surveys to assess the cumulative attack rate. Here, we present the results of a cross-sectional sero-survey of a random sample of residents of a health district in Yaounde, Cameroon, conducted from October 14 to November 26, 2020. Among the 971 participants, the test-adjusted seroprevalence of anti-SARS-CoV-2 IgG antibodies was 29·2% (95% CI 24·3-34·1). This is about 322 times g ...[more]

PMID: 34615863

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Project description:Introduction: Urban informal settlements may be disproportionately affected by the COVID-19 pandemic due to overcrowding and other socioeconomic challenges that make adoption and implementation of public health mitigation measures difficult. We conducted a seroprevalence survey in the Kibera informal settlement, Nairobi, Kenya, to determine the extent of SARS-CoV-2 infection. Methods: Members of randomly selected households from an existing population-based infectious disease surveillance (PBIDS) provided blood specimens between 27 th November and 5 th December 2020. The specimens were tested for antibodies to the SARS-CoV-2 spike protein. Seroprevalence estimates were weighted by age and sex distribution of the PBIDS population and accounted for household clustering. Multivariable logistic regression was used to identify risk factors for individual seropositivity. Results: Consent was obtained from 523 individuals in 175 households, yielding 511 serum specimens that were tested. The overall weighted seroprevalence was 43.3% (95% CI, 37.4 - 49.5%) and did not vary by sex. Of the sampled households, 122(69.7%) had at least one seropositive individual. The individual seroprevalence increased by age from 7.6% (95% CI, 2.4 - 21.3%) among children (<5 years), 32.7% (95% CI, 22.9 - 44.4%) among children 5 - 9 years, 41.8% (95% CI, 33.0 - 51.1%) for those 10-19 years, and 54.9%(46.2 - 63.3%) for adults (≥20 years). Relative to those from medium-sized households (3 and 4 individuals), participants from large (≥5 persons) households had significantly increased odds of being seropositive, aOR, 1.98(95% CI, 1.17 - 1.58), while those from small-sized households (≤2 individuals) had increased odds but not statistically significant, aOR, 2.31 (95% CI, 0.93 - 5.74). Conclusion: In densely populated urban settings, close to half of the individuals had an infection to SARS-CoV-2 after eight months of the COVID-19 pandemic in Kenya. This highlights the importance to prioritize mitigation measures, including COVID-19 vaccine distribution, in the crowded, low socioeconomic settings.

Project description:BackgroundIncreased risk of schistosomiasis in peri-urban and urban towns is not uncommon. An epidemiological survey was carried out in the Tiko Health District (THD), an unmapped transmission focus for urogenital schistosomiasis (UGS), to assess the distribution, intensity, and risk factors associated with the occurrence of UGS.MethodsIn this cross-sectional survey, 12 communities were purposively selected from four health areas (HAs) (Likomba, Holforth, Holforth-Likomba, and Mutengene) in South West Region of Cameroon between June and August 2018. Consenting individuals were enrolled using a convenient sampling technique and administered a semi-structured questionnaire to document information on socio-demographic and water contact behaviour. Urine samples were examined for Schistosoma haematobium infection using test strip, filtration, and microscopy methods. Bivariate and binary logistic regression analyses were used to identify predictors of infection.ResultsThe overall prevalence of UGS in Likomba, Holforth-Likomba and Holforth was 31.5% [95% confidence interval (CI): 28.3-34.8] with geometric mean (GM) egg count of 28.7 (range: 2-450) eggs per 10 ml of urine. S. haematobium infection was not found in Mutengene HA. Infection was unevenly distributed among the HAs, Holforth-Likomba and Holforth being the most and least affected, respectively. The prevalence of infection varied (P < 0.001) among the affected communities, ranging from 12.0 to 56.9%. Infection status of the community related positively (P < 0.001) with proximity to stream (< 100 m), the degree of contact with water and number of improved water sources. Younger age group (5-14 years) [adjusted odds ratio (aOR): 3.7, 95% CI: 1.1-12.2] and intense water contact (degree II) (aOR: 5.2, 95% CI: 3.4-8.1) were associated with increased risk of infection. Similarly, significantly higher egg load was observed among younger aged groups (P = 0.02) and those who carried out intense water contact activities (P < 0.001).ConclusionsGenerally, THD is a moderate risk endemic focus for UGS but prevalence higher than 50.0% was observed in some communities. These findings warrant immediate mass chemotherapy with praziquantel to reduce morbidity. Provision of portable water and health education are proposed measures to reduce and eventually eliminate transmission in the area.

Project description:BackgroundToxoplasmosis is caused by an obligate intracellular tissue protozoan parasite, Toxoplasma gondii that infect humans and other warm-blooded animals. Transmission to humans is by eating raw or inadequately cooked infected meat or through ingestion of oocysts that cats have passed in faeces. Studies have shown life-threatening and substantial neurologic damage in immunocompromised patients; however, 80% of humans remain asymptomatic. The aim of this study was to determine the seroprevalence of Toxoplasma gondii infection in HIV positive patients and the risk factors associated with the infection, and to investigate the correlation between CD4+ T-cell count and toxoplasma specific antibodies as possible predictors of each other amongst HIV patients in the Bamenda Health District of the North West Region of Cameroon.MethodsA cross-sectional study was conducted, in which 325 HIV patients were recruited for administration of questionnaire, serological diagnosis of T. gondii and measurement of CD4+ T-cell count. Bivariate and multivariate logistic regression was used to identify risk factors associated with T. gondii infection while the linear regression was used to investigate the relationship between CD4+ T-cell count and antibody levels against T. gondii.ResultsThe findings showed that, majority (45.8%) of HIV patients suffered from chronic (IgG antibody) infection, and 6.5% from acute (IgM and IgM/IgG antibody) toxoplasma infection. The overall sero-prevalence of T. gondii infection amongst HIV patients was 50.5%. On the whole, 43 men (45.7%) and 127 women (55%) presented with anti- T. gondii antibodies; however, there was no significant difference amongst males and females who were positive to T. gondii infection (p = 0.131). Marital status (p = 0.0003), contact with garden soil (p = 0.0062), and garden ownership (p = 0.009), were factors that showed significant association with T. gondii infection. There was no significant difference (p = 0.909) between the mean CD4+ T-cell count of HIV patients negative for toxoplasma infection (502.7 cells/mL), chronically infected with T. gondii (517.7 cells/mL) and acutely infected with T. gondii (513.1 cells/mL). CD4+ T-cell count was neither a predictor of IgM antibody titer (r = 0.193, p = 0.401), nor IgG antibody titer (r = 0.149, p = 0.519) amongst HIV patients acutely infected with T. gondii.ConclusionThe findings from this study underscore the need to implement preventive and control measures to fight against T. gondii infection amongst HIV patients in the Bamenda Health District.

Project description:ImportanceData from seroepidemiologic surveys measuring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure in diverse communities and ascertaining risk factors associated with infection are important to guide future prevention strategies.ObjectiveTo assess the prevalence of previous SARS-CoV-2 infection across Virginia and the risk factors associated with infection after the first wave of coronavirus disease 2019 (COVID-19) infections in the US.Design, setting, and participantsIn this statewide cross-sectional surveillance study, 4675 adult outpatients presenting for health care not associated with COVID-19 in Virginia between June 1 and August 14, 2020, were recruited to participate in a questionnaire and receive venipuncture to assess SARS-CoV-2 serology. Eligibility was stratified to meet age, race, and ethnicity quotas that matched regional demographic profiles.Main outcomes and measuresThe main outcome was SARS-CoV-2 seropositivity, as measured by the Abbott SARS-CoV-2 immunoglobulin G assay.ResultsAmong 4675 adult outpatients (mean [SD] age, 48.8 [16.9] years; 3119 women [66.7%]; 3098 White [66.3%] and 4279 non-Hispanic [91.5%] individuals) presenting for non-COVID-19-associated health care across Virginia, the weighted seroprevalence was 2.4% (95% CI, 1.8%-3.1%) and ranged from 0% to 20% by zip code. Seroprevalence was notably higher among participants who were Hispanic (10.2%; 95% CI, 6.1%-14.3%), residing in the northern region (4.4%; 95% CI, 2.8%-6.1%), aged 40 to 49 years (4.4%; 95% CI, 1.8%-7.1%), and uninsured (5.9%; 95% CI, 1.5%-10.3%). Higher seroprevalence was associated with Hispanic ethnicity (adjusted odds ratio [aOR], 3.56; 95% CI, 1.76-7.21), residence in a multifamily unit (aOR, 2.55; 95% CI, 1.25-5.22), and contact with an individual with confirmed COVID-19 infection (aOR, 4.33; 95% CI, 1.77-10.58). The sensitivity of serology results was 94% (95% CI, 70%-100%) among those who reported receiving a previous polymerase chain reaction test for COVID-19 infection. Among 101 participants with seropositive results, 67 individuals (66.3%) were estimated to have asymptomatic infection. These data suggested a total estimated COVID-19 burden that was 2.8-fold higher than that ascertained by PCR-positive case counts.Conclusions and relevanceThis large statewide serologic study estimated that 2.4% of adults in Virginia had exposure to SARS-CoV-2, which was 2.8-fold higher than confirmed case counts. Hispanic ethnicity, residence in a multifamily unit, and contact with an individual with confirmed COVID-19 infection were significant risk factors associated with exposure. Most infections were asymptomatic. As of August 2020, the population in Virginia remained largely immunologically naive to the virus.

Dataset Information

SARS-CoV-2 antibody seroprevalence and associated risk factors in an urban district in Cameroon.

Publications

SARS-CoV-2 antibody seroprevalence and associated risk factors in an urban district in Cameroon.

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