ABSTRACT
Background Wearing a mask is one of the simplest ways to reduce the spread of COVID-19. Studies reported poor mask compliance in Greater Chennai Corporation, India. Hence, we described the knowledge, attitude, and practice regarding mask use among adults (≥18 years) in Greater Chennai Corporation, Tamil Nadu, India. Methods We conducted a cross-sectional survey among residents of Greater Chennai Corporation in March 2021. We estimated the sample size to be 203 per strata (slum and non-slum). We used a simple random sampling technique to select 20 locations using a digital map in the slum and non-slum areas. After reaching the location chosen, we selected 10 consecutive households and one adult (≥18 years of age) from each household. We used a validated, semi-structured questionnaire for collecting data regarding knowledge, attitudes, and practices for mask use. We estimated proportions and 95% CI for key variables and compared the variables between slums and non-slums. Results Of 430 participants included in the study, 51.4% were males. The mean (S.D.) age of the participants is 41.1 (14.6) years. The majority (86.7%) of the participants felt that wearing a mask helped in reducing the spread of coronavirus and the knowledge differed (p-value < 0.05) between the slum (81.4%) and non-slum (92.3%). Nearly half (46.5%) of the participants did not like being forced to wear the mask. About 63.9% of the participants reported the practice of mask use while going out which was similar across slums and non-slums. Conclusion Although the knowledge regarding mask use was good among the public, the attitude was unfavorable. We suggest continuous reinforcement by spreading awareness and educating the community on the appropriate use of the mask.
ABSTRACT
We estimated the effectiveness of two doses of the ChAdOx1 nCoV-19 (Covishield) vaccine against any COVID-19 infection among individuals ≥45 years in Chennai, Tamil Nadu, India. A community-based cohort study was conducted from May to September 2021 in a selected geographic area in Chennai. The estimated sample size was 10,232. We enrolled 69,435 individuals, of which 21,793 were above 45 years. Two-dose coverage of Covishield in the 18+ and 45+ age group was 18% and 31%, respectively. Genomic analysis of 74 out of the 90 aliquots collected from the 303 COVID-19-positive individuals in the 45+ age group showed delta variants and their sub-lineages. The vaccine's effectiveness against COVID-19 disease in the ≥45 age group was 61.3% (95% CI: 43.6-73.4) at least 2 weeks after receiving the second dose of Covishield. We demonstrated the effectiveness of two doses of the ChAdOx1 vaccine against the delta variant in the general population of Chennai. We recommend similar future studies considering emerging variants and newer vaccines. Two-dose vaccine coverage could be ensured to protect against COVID-19 infection.
ABSTRACT
Objectives: To describe the public health strategies and their effect in controlling the COVID-19 pandemic from March to October 2020 in Chennai, India. Setting: Chennai, a densely populated metropolitan city in Southern India, was one of the five cities which contributed to more than half of the COVID-19 cases in India. Participants: We collected the de-identified line list of all the 192,450 COVID-19 case-patients reported from 17 March to 31 October 2020 in Chennai and their contacts for the analysis. We defined a COVID-19 case-patient based on the RT-PCR positive test in one of the Government approved labs. Outcome measures: The primary outcomes of interest were incidence of COVID-19 per million population, case fatality ratio, deaths per million and the effective reproduction number (Rt). We also analysed the indicators for surveillance, testing, contact tracing and isolation. Results: Of the 192,450 RT-PCR confirmed COVID-19 case-patients reported in Chennai from 17 March-31 October 2020, 114,889 (60%) were males. The highest incidence was 41,064 per million population among the 61-80 years. The incidence peaked during June 2020 at 5239 per million and declined to 3,627 per million in October 2020. The city reported 3,543 deaths, with a case fatality ratio (CFR) of 1.8% and the crude death rate was 431 per million. When lockdown began, Rt was high (4.2) in March and fluctuated from April to June 2020. The Rt dropped below one by the first week of July and remained so until October 2020, even with the relaxation of restrictions Conclusion: The combination of public health strategies controlled the COVID-19 epidemic in a large, densely populated city in India. We recommend continuing the interventions to prevent resurgence, even as vaccination is being rolled out.
Subject(s)
COVID-19ABSTRACT
We conducted a cross-sectional survey to estimate the seroprevalence of IgG against severe acute respiratory syndrome coronavirus 2 in Chennai, India. Among 12,405 serum samples tested, weighted seroprevalence was 18.4% (95% CI 14.8%-22.6%). These findings indicate most of the population of Chennai is still susceptible to this virus.