Face mask use in the city of Chennai, India: Results from three serial cross-sectional surveys, 2021.

INTRODUCTION: The Government of Tamil Nadu, India, mandated wearing face masks in public places to combat the COVID-19 pandemic. We established face mask surveillance and estimated the prevalence of appropriate mask use (covering the nose, mouth, and chin) in the slums and non-slums of Chennai at different time points in 2021. METHODS: We conducted three serial cross-sectional surveys in the outdoors and indoors of Chennai in March, July, and October 2021. We observed the mask wearing among 3200 individuals in the outdoors and 1280 in the indoors. We divided the outdoor and indoor locations into slums and non-slums. In October 2021, we also surveyed 150 individuals from each of the 11 shopping malls in the city. We calculated the proportions and 95% confidence interval (95%CI) for the appropriate mask use in the outdoor, indoor, and malls by age, gender, region, and setting (slum and non-slum). RESULTS: We observed 3200 individuals in the outdoor and 1280 individuals in the indoor setting, each from a slum and non-slum, during the three rounds of the study. In outdoor and indoors, males comprised three-fourths and middle-aged individuals were half the study population. Mask compliance changed significantly with time (p-value <0.001). Males consistently demonstrated better compliance in all rounds. The south region had the highest mask compliance in slums indoors and outdoors in rounds 4 and 5. Young adults had the highest mask compliance in both outdoor slums and non-slums in all rounds. Overall mask compliance in shopping malls was 57% (95% CI: 48-65). CONCLUSION: The mask compliance in Chennai outdoors during the COVID-19 pandemic was less than 50%, with variations across time points by gender, age groups, and geographical locations. We must develop more effective communication strategies for older age groups and crowded indoor settings.

Knowledge, attitude, and practice towards face mask use among residents of Greater Chennai Corporation, India, March 2021.

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.

Effectiveness of the ChAdOx1 nCoV-19 Coronavirus Vaccine (CovishieldTM) in Preventing SARS-CoV2 Infection, Chennai, Tamil Nadu, India, 2021.

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.

Epidemiology of COVID-19 and effect of public health interventions, Chennai, India, March - October 2020

ObjectivesTo describe the public health strategies and their effect in controlling the COVID-19 pandemic from March to October 2020 in Chennai, India. SettingChennai, 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. ParticipantsWe 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 measuresThe 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. ResultsOf 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 ConclusionThe 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. StrengthsO_LIWe did a comprehensive analysis of COVID-19 strategies and outcome in a large, densely populated metropolitan city in India. C_LIO_LIWe documented that the community-centric public health strategies were feasible and effective in controlling the COVID-19 outbreak even in a large, thickly populated city C_LIO_LIThe lessons learnt are relevant to similar settings in low-and middle-income countries. Given the ongoing multiple waves of COVID-19 and the difficulty in controlling the transmission, our experience and lessons learnt will be valuable for policymakers and scientific advisors globally C_LI LimitationsO_LIWe analysed the data available from the GCC database and not from the hospitals where patients with moderate to severe illness were admitted. Hence, we could not report the severity of illness among admitted patients. C_LIO_LISecond, the COVID-19 incidence might have been underestimated while testing was low during the early phase of the epidemic C_LI

Population-Based Serosurvey for Severe Acute Respiratory Syndrome Coronavirus 2 Transmission, Chennai, India.

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.

Understanding why at-risk population segments do not seek care for tuberculosis: a precision public health approach in South India.

INTRODUCTION: Delaying care-seeking for tuberculosis (TB) symptoms is a major contributor to mortality, leading to worse outcomes and spread. To reduce delays, it is essential to identify barriers to care-seeking and target populations most at risk of delaying. Previous work identifies barriers only in people within the health system, often long after initial care-seeking. METHODS: We conducted a community-based survey of 84 625 households in Chennai, India, to identify 1667 people with TB-indicative symptoms in 2018-2019. Cases were followed prospectively to observe care-seeking behaviour. We used a comprehensive survey to identify care-seeking drivers, then performed multivariate analyses to identify care-seeking predictors. To identify profiles of individuals most at risk to delay care-seeking, we segmented the sample using unsupervised clustering. We then estimated the per cent of the TB-diagnosed population in Chennai in each segment. RESULTS: Delayed care-seeking characteristics include smoking, drinking, being employed, preferring different facilities than the community, believing to be at lower risk of TB and believing TB is common. Respondents who reported fever or unintended weight loss were more likely to seek care. Clustering analysis revealed seven population segments differing in care-seeking, from a retired/unemployed/disabled cluster, where 70% promptly sought care, to a cluster of employed men who problem-drink and smoke, where only 42% did so. Modelling showed 54% of TB-diagnosed people who delay care-seeking might belong to the latter segment, which is most likely to acquire TB and least likely to promptly seek care. CONCLUSION: Interventions to increase care-seeking should move from building general awareness to addressing treatment barriers such as lack of time and low-risk perception. Care-seeking interventions should address specific beliefs through a mix of educational, risk perception-targeting and social norms-based campaigns. Employed men who problem-drink and smoke are a prime target for interventions. Reducing delays in this group could dramatically reduce TB spread.

A Step Towards Improving Food Safety in India: Determining Baseline Knowledge and Behaviors Among Restaurant Food Handlers in Chennai.

With the establishment of the Food Safety and Standards Authority of India (FSSAI) and new food safety regulations, a precedent has been set to prevent foodborne illness in India. The objective of the authors' study was to identify knowledge gaps among food handlers in Chennai, Tamil Nadu, to establish priorities for future intervention. A 44-question survey was administered to 156 food handlers at 36 restaurants in Chennai between April and June of 2011. The overall mean knowledge score was 49% and knowledge gaps related to hand hygiene, proper food cooking and holding temperatures, and cross contamination were identified. Food handlers with a Medical Fitness Certificate scored significantly higher than those without a certificate, after controlling for food safety training and level of education (p < .05). As the FSSAI standards now require a medical certificate for restaurant licensure and registration, consideration should be given to include an educational component to this certification with an explanation of expected food safety behavior.