ABSTRACT
Background Seroprevalence studies of coronavirus disease 2019 (COVID-19) assess the degree of undetected transmission in the community. Different groups, such as healthcare workers (HCWs), garment workers, and others, are deemed vulnerable due to their workplace hazards and immense responsibility. Purpose The present study was conducted to estimate the seroprevalence of anti-SARS-CoV-2 antibody (IgG) and its association with different explanatory variables. Further, the antibody was quantified to assess the increasing or decreasing trend over different intervention periods and according to other factors. Methodology This cross-sectional study observed health workers - doctor, nurse, hospital staff, etc. in and outpatients (non-COVID-19) and garments workers of Chattogram metropolitan area (CMA, N=748) from randomly selected six government and private hospitals and two garment factories. Study subjects were included upon written consent, fulfilling specific inclusion criteria. Venous blood was collected following standard aseptic methods. Qualitative and quantitative ELISA was used to identify and quantify antibodies (IgG) in serum samples. Descriptive, univariable, and multivariable statistical analysis was performed. Results Overall seroprevalence was estimated as 66.99% (95% CI: 63.40%-70.40%). Seroprevalence among HCWs, in and outpatients, and garments workers were 68.99 % (95% CI: 63.8%-73.7%), 81.37 % (95% CI: 74.7%-86.7%), and 50.56 % (95% CI: 43.5%-57.5%), respectively. Seroprevalence was 44.47 % (95% CI: 38.6%-50.4%) in the non-vaccinated population while it was significantly ( p <0.001) higher in the population receiving the first dose (61.66 %, 95% CI: 54.8%-68.0%) and both (first and second) doses of vaccine (100%, 95% CI: 98.4%-100%). The mean titer of the antibody was estimated as 255.46 DU/ml and 159.08 DU/ml in the population with both doses and one dose of vaccine, respectively, compared to 53.71 DU/ml of the unvaccinated population. A decreasing trend in the titer of antibodies with increasing time after vaccination was observed. Conclusions Seroprevalence and mean antibody titer varied according to different factors in this study. The second dose of vaccine significantly increased the seroprevalence and titer, which decreased to a certain level over time. Although antibody was produced following natural infection, the mean titer was relatively low compared to antibody after vaccination. This study emphasizes the role of the vaccine in antibody production. Based on the findings, interventions like continuing extensive mass vaccination of the leftover unvaccinated population and bringing the mass population with a second dose under a third dose campaign might be planned.
Subject(s)
COVID-19ABSTRACT
The present global endeavor to uncover the most effective vaccines against severe acute respiratory syndrome coronavirus (SARS-CoV-2) that can tremendously prevent transmission, infection and significantly reduce public health risk. COVID-19 vaccination program is underway in different parts of the world including Bangladesh but till to date there is no available health data revealed among the vaccinated peoples. We conducted a cross-sectional study from February 15 to April 15, 2021 to assess the health status of 1st dose Oxford-AstraZeneca vaccinated individuals infected with SARS CoV-2. Standard virological method, real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) was performed to detect SARS-CoV-2 and the different health parameters from vaccinated individuals were collected through direct mobile phone contact using pre-structured questionnaires. A total of 6146 suspected samples were tested and 1752 were found positive for SARS-CoV-2, of them 200 individuals were identified who received 1st dose of COVID-19 vaccine. Within the test period, majority of male (65.6%) and female (34.4%) carried moderate numbers of viruses which comprise between 30.01-35 cyclic threshold (ct) values. Among the vaccinated individuals, 165 (82.5%; 95% CI: 76.51 - 87.5) persons were not hospitalized and 177 (88.5%; 95% CI: 83.24 - 92.57) did not show any respiratory difficulties. Only a few (16) (8%; 95% CI: 4.64 - 12.67) of COVID-19 positive patients needed extra oxygen support and 199 (99.5%; 95% CI: 97.25 - 99.99) individuals did not require any intensive care unit (ICU) interference. Overall, oxygen saturation was recorded around 96.8% and respiratory difficulties did not extend more than 5 days, irrespective of age and sex during the infection period. Within the vaccinated COVID-19 positive individuals 113 (56.5%; 95% CI: 49.33 - 63.48) and 111(55.5%; 95% CI: 48.32 - 62.51) persons have normal physiological taste and smell. However, we have found a larger proportion of vaccinated persons (129) (64.5%; 95% CI: 57.44 - 71.12) carrying different comorbidity, among them high blood pressure 36 (27.9%; 95% CI, 20.37 - 36.48) and diabetes 32 (24.8%; 95% CI: 17.63 - 33.18) were found more prevalent. Moreover, the significant finding of the present study was 199 (99.5%; 95% CI: 97.25 - 99.99) vaccinated individuals survived with good health conditions and became negative in RT-qPCR. The authors suggest that health risk assessment among the COVID-19 vaccinated persons when infected with SARS-CoV-2 is crucial and time demanding task for the whole world. However, the present study illustrates that the administration of the 1st dose Oxford-AstraZeneca vaccine significantly reduces health risk during the COVID-19 infection period.