SARS-CoV-2 Seroprevalence after Third Wave of Infections, South Africa.
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ABSTRACT:
SUBMITTER: Kleynhans J
PROVIDER: S-EPMC9045427 | biostudies-literature | 2022 May
REPOSITORIES: biostudies-literature
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SARS-CoV-2 Seroprevalence after Third Wave of Infections, South Africa.
Kleynhans Jackie J Tempia Stefano S Wolter Nicole N von Gottberg Anne A Bhiman Jinal N JN Buys Amelia A Moyes Jocelyn J McMorrow Meredith L ML Kahn Kathleen K Gómez-Olivé F Xavier FX Tollman Stephen S Martinson Neil A NA Wafawanaka Floidy F Lebina Limakatso L du Toit Jacques D JD Jassat Waasila W Neti Mzimasi M Brauer Marieke M Cohen Cheryl C
Emerging infectious diseases 20220323 5
By November 2021, after the third wave of severe acute respiratory syndrome coronavirus 2 infections in South Africa, seroprevalence was 60% in a rural community and 70% in an urban community. High seroprevalence before the Omicron variant emerged may have contributed to reduced illness severity observed in the fourth wave. ...[more]
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Project description:BackgroundInequality is rife throughout South Africa. The first wave of COVID-19 may have affected people in lower socioeconomic groups worse than the affluent. The SARS-CoV-2 seroprevalence and the specificity of anti-SARS-CoV-2 antibody tests in South Africa is not known.MethodsWe tested 405 volunteers representing all socioeconomic strata from the workforce of a popular shopping and tourist complex in central Cape Town with the Abbott SARS-CoV-2 IgG assay. We assessed the association between antibody positivity and COVID-19 symptom status, medical history, and sociodemographic variables. We tested 137 serum samples from healthy controls collected in Cape Town prior to the COVID-19 pandemic, to confirm the specificity of the assay in the local population.ResultsOf the 405 volunteers tested one month after the first peak of the epidemic in Cape Town, 96(23.7%) were SARS-CoV-2 IgG positive. Of those who tested positive, 46(47.9%) reported no symptoms of COVID-19 in the previous 6 months. Seropositivity was significantly associated with living in informal housing, residing in a subdistrict with low income-per household, and having a low-earning occupation. The specificity of the assay was 98.54%(95%CI 94.82%-99.82%) in the pre-COVID controls.ConclusionsThere is a high background seroprevalence in Cape Town, particularly in people of lower socioeconomic status. Almost half of cases are asymptomatic, and therefore undiagnosed by local testing strategies. These results cannot be explained by low assay specificity.
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Project description:BackgroundRapid antigen tests detecting SARS-CoV-2 were shown to be a useful tool in managing the COVID-19 pandemic. Here, we report on the results of a prospective diagnostic accuracy study of four SARS-CoV-2 rapid antigen tests in a South African setting.MethodsRapid antigen test evaluations were performed through drive-through testing centres in Durban, South Africa, from July to December 2021. Two evaluation studies were performed: nasal Panbio COVID-19 Ag Rapid Test Device (Abbott) was evaluated in parallel with the nasopharyngeal Espline SARS-CoV-2 Ag test (Fujirebio), followed by the evaluation of nasal RightSign COVID-19 Antigen Rapid test Cassette (Hangzhou Biotest Biotech) in parallel with the nasopharyngeal STANDARD Q COVID-19 Ag test (SD Biosensor). The Abbott RealTime SARS-CoV-2 assay was used as a reference test.ResultsEvaluation of Panbio and Espline Ag tests was performed on 494 samples (31% positivity), while the evaluation of Standard Q and RightTest Ag tests was performed on 539 samples (13.17% positivity). The overall sensitivity for all four tests ranged between 60 and 72% with excellent specificity values (> 98%). Sensitivity increased to > 80% in all tests in samples with cycle number value < 20. All four tests performed best in samples from patients presenting within the first week of symptom onset.ConclusionsAll four evaluated tests detected a majority of the cases within the first week of symptom onset with high viral load.
| S-EPMC10369830 | biostudies-literature
Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections may be underestimated because of limited access to testing. We measured SARS-CoV-2 seroprevalence in South Africa every 2 months during July 2020-March 2021 in randomly selected household cohorts in 2 communities. We compared seroprevalence to reported laboratory-confirmed infections, hospitalizations, and deaths to calculate infection-case, infection-hospitalization, and infection-fatality ratios in 2 waves of infection. Post-second wave seroprevalence ranged from 18% in the rural community children <5 years of age, to 59% in urban community adults 35-59 years of age. The second wave saw a shift in age distribution of case-patients in the urban community (from persons 35-59 years of age to persons at the extremes of age), higher attack rates in the rural community, and a higher infection-fatality ratio in the urban community. Approximately 95% of SARS-CoV-2 infections were not reported to national surveillance.
| S-EPMC8632160 | biostudies-literature
Project description: Not available
| S-EPMC9259009 | biostudies-literature
Project description:In 2020, Korea Disease Control and Prevention Agency reported three rounds of surveys on seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in South Korea. SARS-CoV-2 is the virus which inflicts the coronavirus disease 2019 (COVID-19). We analyze the seroprevalence surveys using a Bayesian method with an informative prior distribution on the seroprevalence parameter, and the sensitivity and specificity of the diagnostic test. We construct the informative prior of the sensitivity and specificity of the diagnostic test using the posterior distribution obtained from the clinical evaluation data. The constraint of the seroprevalence parameter induced from the known confirmed coronavirus 2019 cases can be imposed naturally in the proposed Bayesian model. We also prove that the confidence interval of the seroprevalence parameter based on the Rao's test can be the empty set, while the Bayesian method renders interval estimators with coverage probability close to the nominal level. As of the 30th of October 2020, the 95% credible interval of the estimated SARS-CoV-2 positive population does not exceed 318, 685, approximately 0.62% of the Korean population.Supplementary informationThe online version contains supplementary material available at 10.1007/s42952-021-00131-7.
| S-EPMC8142885 | biostudies-literature
Project description:ObjectivesAfter South Africa's second wave of COVID-19, this study estimated the SARS-CoV-2 seroprevalence among pregnant women in inner-city Johannesburg, South Africa.MethodsIn this cross-sectional survey, 500 non-COVID-19-vaccinated pregnant women (aged ≥12 years) were enrolled, and demographic and clinical data were collected. Serum samples were tested using the Wantai SARS-CoV-2 spike Ab ELISA and Roche Elecsys® Anti-SARS-CoV-2 nucleocapsid antibody assays. Seropositivity was defined as SARS-CoV-2 antibodies on either (primary) or both (secondary) assays. Univariate Poisson regression assessed risk factors associated with seropositivity.ResultsMedian age was 27.4 years and HIV prevalence 26.7%. SARS-CoV-2 seroprevalence was 64.0% (95% CI:59.6%-68.2%) on the primary and 54% (95%CI:49.5-58.4) on the secondary measure. Most (96.6%) SARS-CoV-2-seropositive women reported no symptoms. On the Roche assay, we detected lower seroprevalence among women living with HIV (WLHIV) compared to HIV uninfected women (48.9% vs 61.7%, p=0.018), and especially low levels among WLHIV with a CD4<350 cells/ml compared to women without immune suppression (22.2% vs 56.4%, prevalence rate ratio=0.4; 95%CI:0.2-0.9; p=0.046).ConclusionsPregnant women attending routine antenatal care had a high SARS-CoV-2 seroprevalence after the 2nd wave in South Africa, with most having had asymptomatic infections. Seroprevalence surveys in pregnant women present a feasible method of monitoring the course of the pandemic over time.
| S-EPMC9637015 | biostudies-literature
Project description:We conducted a seroprevalence study using convenient residual sera samples from the Slovenian population collected after the end of the Omicron BA.1 pandemic wave. Serum samples were tested for spike glycoprotein (anti-S) and nucleocapsid protein (anti-N) antibodies. Participants’ data regarding confirmed infection and vaccination was obtained from national registries. Anti-S antibodies were detected in 2439 (84.1%) of 2899 sera from persons aged 0–90 years, with the lowest prevalence in the 0–17 age group. The proportion of anti-N positives was the lowest in the ≥70 age group. The proportion of anti-N positives was significantly higher among participants with confirmed past infection and among those who had never been vaccinated. In participants who had not been notified as infected and who had never been vaccinated, the seroprevalence of anti-S and anti-N antibodies was 53% and 35.5%, respectively. From the time of serum collection to mid-November 2022, 445 participants (15.3%) tested positive for SARS-CoV-2, with higher odds in seronegative participants, participants in the 40–59 age group, and those without notified previous infection. Vaccination status and gender had no significant effects on infection risk. This study underlines the importance of serosurveys in understanding the development of the pandemic.
| S-EPMC9959557 | biostudies-literature
Project description:BackgroundDespite the high COVID-19 morbidity and mortality rates across the world, the reported rates in sub-Saharan Africa (SSA), which has a higher burden of other infectious diseases and overwhelmed healthcare systems, remain relatively low. This study aims to better understand the potential factors that contribute to this phenomenon, especially among cancer patients who are considered as a high-risk group for developing severe COVID-19.MethodsPlasma samples collected during the COVID-19 pandemic from SARS-CoV-2 unvaccinated cancer and potential blood donor populations were analyzed for SARS-CoV-2 (spike and nucleocapsid proteins) antibodies by an immunofluorescence assay. The relationships between SARS-CoV-2 seroprevalences and study variables were determined using a logistic regression analysis.ResultsHigh seroprevalence against the SARS-CoV-2 spike and nucleocapsid proteins were found among the SARS-CoV-2 unvaccinated COVID-19 pandemic populations in SSA. However, the cancer patients demonstrated a lower seroprevalence compared to potential blood donors. There was also an association between mild COVID-19 symptoms with prior tuberculosis vaccination among cancer patients.ConclusionCancer patients in SSA tend to have a relatively lower SARS-CoV-2 seroprevalence compared to potential blood donors recruited from the same geographic locations during the COVID-19 pandemic. More study is required to determine its cause and potential impact on SARS-CoV-2 vaccination among cancer patients.
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Project description:ObjectivesThe burden of SARS-CoV-2 infection in people living with HIV (PLHIV) in South Sudan is unknown.MethodsWe conducted a cross-sectional seroprevalence survey of SARS-CoV-2 immunoglobulin (Ig) G antibodies and other diseases of public health importance (strongyloidiasis, toxoplasmosis) in PLHIV in South Sudan during April 1, 2020-April 30, 2022. We used a multiplex SARS-CoV-2 immunoassay to detect IgG antibodies targeting the SARS-CoV-2 spike, receptor binding domain, and nucelocapsid (N) proteins, and antigens for other pathogens (Strongyloides stercoralis and Toxoplasma gondii).ResultsAmong 3518 samples tested, seroprevalence of IgG antibodies to SARS-CoV-2 spike protein and receptor binding domain 591 and nucleocapsid ranged from 1.4% (95% confidence interval [CI]: 0.9-2.1%) in April-June 2020 to 53.3% (95% CI: 49.5-57.1%) in January-March 2022. The prevalence of S. stercoralis IgG ranged between 27.3% (95% CI: 23.4-31.5%) in October-December 2021 and 47.2% (95% CI: 37.8-56.8%) in July-September 2021, and, for T. gondii IgG, prevalence ranged from 15.5% (95% CI: 13.3-17.9%) in April-June 2020 to 36.2% (95% CI: 27.4-46.2%) July-September 2021.ConclusionsBy early 2022, PLHIV in South Sudan had high rates of SARS-CoV-2 seropositivity. Surveillance of diseases of global health concern in PLHIV is crucial to estimate population-level exposure and inform public health responses.
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Project description:ObjectiveThe objective of this study was to determine the proportion of the Anambra State population that had been infected by the SARS-CoV-2 virus and developed antibodies before the second wave.MethodsThe WHO-recommended health facility-based cross-sectional approach was adapted for this survey. Between 8th and 15th December 2020, 3142 participants across the 21 local government areas (LGAs) of the State, aged one year and over, attending randomly selected health facilities, were recruited. Demographic and symptom-related information were collected from the participants as well as whole peripheral blood, which was tested for SARS-CoV-2 IgG and IgM with rapid test kits.Results425 participants tested positive for IgG only, 74 for IgM only, while 54 were positive for both IgG and IgM. Overall, 553 positives were recorded, giving a crude seroprevalence of 17.6% (95% CI = 16.26 - 18.98). It ranged widely from 31.9% (95% CI = 24.43 - 40.22) in Onitsha North LGA to 5.4% (95% CI = 2.19 - 10.78) in Awka north. Bayesian Adjustments yielded a state seroprevalence of 16.1%.ConclusionOne in six state residents had been infected by SARS-CoV-2 and developed antibodies before the second wave. All LGAs, age groups, sexes, and settlement types were affected by COVID-19. A large proportion of the population remained susceptible to SARS-CoV-2.
| S-EPMC8288214 | biostudies-literature