Fig 1.
Epidemiological summary of the COVID-19 outbreak in Karnataka, India from 9 March to 21 July 2020 (n = 71068).
[A] Number of daily confirmed cases across time. [B] Density scatterplot showing daily confirmed cases for various ages across time. [C] Distribution of population, COVID-19 cases and COVID-19 deaths across age groups. 10-year age brackets have been used starting from 0–9 years, and the last bracket is ≥80 years. [D] Daily confirmed cases across time stratified by origin of infection- imported international, imported domestic, local with known origin, and local with unknown origin.
Table 1.
Distribution of 71068 COVID-19 cases across time and categories and their demographic characteristics and case fatality rate (Karnataka, India; up to 21 July 2020).
Fig 2.
Transmission networks of three largest clusters of SARS-CoV-2 cases in Karnataka, India up to 21 July 2020.
The networks indicate the heterogeneity in transmission from infected cases, with a few patients causing most secondary cases. The Bellary cluster occurred in June and July, during which symptomatic status of cases was not available.
Fig 3.
Transmission characteristics of SARS-CoV-2 in Karnataka, India.
[A, B] Observed offspring distribution of [A] 956 cases with confirmed forward contact tracing and [B] 394 cases linked to the three largest clusters (Bellary cluster, Delhi convention cluster, and Pharmaceutical company cluster). Bars show observed frequency of the number of individuals infected by each case. [C, D] Proportion of all onward transmission (solid line) and proportion of all contacts (dashed line) due to a given proportion of infectious cases, where infectious cases are ranked by number of offspring cases (ie, infectiousness), for [C] 956 cases with confirmed forward contact tracing and [D] 394 cases linked to the three largest clusters. [E, F] Serial interval distribution of SARS-CoV-2 infections in Karnataka, India and the fitted gamma, lognormal and weibull distributions, among [E] 53 infector-infectee pairs and [F] 51 infector-infectee pairs with positive serial intervals. 10000 bootstraps were used for estimating the 95% confidence limits shown by the shaded bands.
Table 2.
Secondary attack rate of SARS-CoV-2 among 16715 contacts of 956 index cases (Karnataka, India; up to 1 June 2020).
Table 3.
Risk of SARS-CoV-2 infection among 16715 contacts of 956 index cases (Karnataka, India; up to 1 June 2020).
Table 4.
Symptomatic proportion and risk of developing symptoms among 3404 COVID-19 cases (Karnataka, India; up to 1 June 2020).
Fig 4.
Case fatality rate COVID-19 cases stratified by age and sex in Karnataka, India up to 21 July 2020 (n-71068).
Bars represent mean CFR for that subgroup (value shown above bars) with error bars showing the 95% confidence intervals.