Serosurveys to detect SARS-CoV-2 antibodies among high-risk groups in six urban cities of Odisha, India.

INTRODUCTION: Personnel involved in essential services or residing in high-risk areas during the COVID-19 pandemic are at increased risk of getting infected. We evaluated the proportion of personnel infected in several high-risk groups in Odisha using seroprevalence studies. METHODOLOGY: During July to November, 2020, individuals from multiple high-risk groups in 6 urban cities (Bhubaneswar, Berhampur, Cuttack, Malkangiri, Paralakhemundi, and Rourkela) in Odisha, India, were recruited to the study after obtaining written informed consent. Blood samples collected from the study participants were tested for IgG antibodies against COVID-19 in Roche Cobas e441 (Roche Diagnostics, Rotkreuz, Switzerland). Information on socio-demographic variables, association with a confirmed or suspected case, and other details were collected using an electronic data capture tool and analysed with a statistical software. RESULTS: The overall COVID-19 seroprevalence was 34.9% (95%CI 33.6-36.2) among the 5434 individuals. The seroprevalence varied from 21.8% (95% CI, 19.6-24.1) in Rourkela to 54.9% (95% CI, 51.5-58.2) in Bhubaneswar. Seropositivity was maximum among prisoners (47.7%), followed by municipality/ sanitation staff (43.5%), and other office going staff (40.8%). Multivariate logistic regression indicated that participants aged 18-29 years, 30-44 years, residents of slums and vending zone, municipality staff, prisoners, residents of urban cities Malkangiri, Cuttack, Paralakhemundi, Bhubaneswar and those with previous history of COVID-19 were independent co-relates of seropositivity. CONCLUSIONS: The risk of COVID-19 varied among the high-risk groups of Odisha. Periodic seroprevalence studies in future are essential to protect the high-risk personnel involved in frontline activities during the pandemic.

Effectiveness of the BBV-152 and AZD1222 vaccines among adult patients hospitalized in tertiary hospitals in Odisha with symptomatic respiratory diseases: A test-negative case-control study.

Two vaccines, namely BBV-152 (COVAXIN®) and AZD1222 (COVISHIELD™), were deployed against SARS-CoV-2 in India from January 16, 2021. Frontline health care workers were vaccinated first, followed by the adult population. However, limited data on vaccine effectiveness are available for the population of India. Therefore, we aimed to evaluate the effectiveness of two doses of each of these two common vaccines against COVID-19 infection among hospitalized patients with pulmonary conditions. We adopted a test-negative case-control design and recruited a sample of adults who were admitted to one of six tertiary care hospitals in Odisha. All participants were hospitalized patients with COVID-19-like pulmonary signs and symptoms. Participants who tested positive for SARS CoV-2 via RT-PCR were treated as cases, and those who tested negative were treated as controls. Logistic regression, adjusted for participants' age, sex, and number of comorbidities, was used to calculate the effectiveness of the two vaccines, using the formula: 100*(1 - adjusted odds ratio). Between March and July of 2021, data were collected from 1,614 eligible adults (864 cases and 750 controls). Among all participants, 9.7% had received two doses of one of the two COVID-19 vaccines. Vaccine effectiveness was 74.0% (50.5%-86.0%) for two doses of BBV-152 and 79.0% (65.4%-87.2%) for two doses of AZD1222. Thus, two doses of either BBV-152 or AZD1222 nCoV-19 vaccine were found to be substantially effective in protecting against COVID-19-related infection.