ObjectivesTo study the percentage seropositivity for SARS-CoV-2 to understand the pandemic status and predict the future situations in Ahmedabad.Study designCross-sectional study.SettingsField area of Ahmedabad Municipal Corporation.ParticipantsMore than 30 000 individuals irrespective of their age, sex, acute/past COVID-19 infection participated in the serosurvey which covered all the 75 Urban Primary Health Centres (UPHCs) across 48 wards and 7 zones of the city. Study also involved healthcare workers (HCWs) from COVID-19/non-COVID-19 hospitals.InterventionsSeropositivity of IgG antibodies against SARS-CoV-2 was measured as a mark of COVID-19 infection.Primary and secondary outcomesSeropositivity was used to calculate cumulative incidence. Correlation of seropositivity with available demographic detail was used for valid and precise assessment of the pandemic situation.ResultsFrom 30 054 samples, the results were available for 29 891 samples and the crude seropositivity is 17.61%. For all the various age groups, the seropositivity calculated between 15% and 20%. The difference in seropositivity for both the sex group is statistically not significant. The seropositivity is significantly lower (13.64%) for HCWs as compared with non-HCWs (18.71%). Seropositivity shows increasing trend with time. Zone with maximum initial cases has high positivity as compared with other zones. UPHCs with recent rise in cases are leading in seropositivity as compared with earlier and widely affected UPHCs.ConclusionsThe results of serosurveillance suggest that the population of Ahmedabad is still largely susceptible. People still need to follow preventive measures to protect themselves till an effective vaccine is available to the people at large. The data indicate the possibility of vanishing immunity over time and need further research to cross verify with scientific evidences.

Background Health Care Workers (HCWs) are at higher risk for Covid19. Sero-surveillance among HCWs using IgG antibodies can add further value to the scientific findings. Objectives To estimate seropositivity among HCWs and to correlate it with various factors affecting seropositivity. Methods Population based large scale sero-surveillance among HCWs was carried out during second half of August’20 in Ahmedabad using “Covid-Kavach” IgG Antibody Detection ELISA kits. Seropositivity among HCWs was estimated and compared with various demographic & other factors to understand their infection & immunity status. Proportions and Z-test were used as appropriate. Results As on August’20, Seropositivity among HCWs from Ahmedabad is 23.65% (95% Confidence Interval 21.70–25.73%). Seropositivity of 25.98% (95%CI 23.47–28.66) among female HCWs is significantly higher than 19.48% (95%CI 16.53–22.80) among male HCWs. The zone wise positivity among HCWs closely correlate with cases reported from the respective zone. The sero-positivity among HCWs from the earliest and worst affected zones have lower level of seropositivity as compared to the zones affected recently. This might be pointing towards the fact that the IgG Antibodies may not be long lasting. Conclusion As on August 2020, the seropositivity of 23.65% in HCWs indicate high level of disease transmission and higher risk of infection among HCWs in Ahmedabad. The seropositivity is significantly higher among female HCWs. Zone wise seropositivity, closely correlate with the reported cases from the respective zone. Their comparison also indicates the possibility of reducing IgG seropositivity, which necessitates further in-depth scientific research to generate greater scientific evidences.

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Background: Assessing population based seroprevalence can help in monitor the pandemic, and suggest appropriate corrective public health measures. Aims and Objectives: To study seroprevalence of IgG antibodies against SARS-CoV2 to understand the pandemic status and deriving valid conclusions for guiding the public health measures for managing the covid19 pandemic. Materials and Methods: A serosurveillance study was carried out using population based stratified sampling for the general population of Ahmedabad city. Seroprevalence for Cases, Contacts and Health Care Workers (HCWs) was also estimated as separate additional categories. The seroprevalence was compared with various demographic factors for valid and precise predictions regarding the immunity status of the population. Results: As on October 2020, the seroprevalence for IgG antibodies against SARS-CoV2 in the general population of Ahmedabad is 24.20% (95% Confidence Interval 23.57%–24.85%) The sero-positivity has increasing trend with age and is higher among females (24.83%) than males (23.72%) but is statistically not significant. The zone wise positivity ranged from 18.70% to 33.52%. The seropositivity among HCWs, contacts and cases are 20.84%, 26.05% and 54.51% respectively and it closely correlate with the risk. Conclusion: As on October 2020, general population demonstrate a seropositivity of 24.20%. The seropositivity among various groups is according to the risk of contracting the disease. Results also indicate the possibility of undetectable level or disappearing IgG during the post-covid period. Results also indicate that the preventive measures must be strongly followed for continued control of the pandemic situation till an effective vaccine is provided to the people at large.

Introduction: The relative contributions of racial and environmental factors to the higher risk of stroke in people of African ancestry are not clear due to limited opportunities to evaluate stroke type and risk among indigenous Africans, in comparison with Africans in diaspora and their host populations. This knowledge could provide insights into avenues for similar vs. unique approaches to managing stroke risk in Africans. Objective: To compare the pattern of stroke and contribution of vascular risk factors to stroke among indigenous Africans, African Americans and European Americans. Methods: SIREN is a large multicenter case-control study involving several sites in West Africa, the ancestral home of 71% African Americans, whilst REGARDS is a cohort study including African and European Americans in the United States. Stroke diagnosis and type were confirmed using CT or MRI scan. Traditional vascular risk factors were assessed using history, physical examination and laboratory investigations. We compared data from acute stroke cases age≥55 years in SIREN and REGARDS in the distribution of key socio-demographic and clinical risk factors based on harmonized standard definitions. Results: There were 811 stroke subjects in the SIREN population (A) and 452 African Americans (B) and 665 European Americans (C) from the REGARDS study with a progressive increment in mean age of 68.0 ± 9.3, 73.0 ± 8.3 and 76.0 ± 8.3 years respectively, p<0.0001. Hemorrhagic stroke occurred in 291/811 (27.0%), 36/452 (8.0%) and 36/665 (5.4%), in A, B, and C (p < 0.001) respectively. There were significant differences in prevalence of vascular risk factors among the three groups namely hypertension: 92.8%, 82.5% & 64.2%, p<0.01; mean LDL cholesterol (mg/dl): 121±52, 116±32, 110±33 (p< 0.03); cardiac diseases: 12.5%, 25.0% & 31.7% (p< 0.01); sedentary lifestyle:8%, 37.7% and 34.0% (p<0.001); and 2.0%, 18.3% & 14.4% were current smokers in A, B and C respectively (p<0.001). Conclusion: Environmental risk factors such as cigarette smoking may contribute to the higher proportion of ischemic stroke in African-Americans compared to indigenous Africans, while racial factors may contribute to the higher proportion of hypertension among stroke subjects of African ancestry.