Incubation Period and Reproduction Number for Novel Coronavirus 2019 (COVID-19) Infections in India (original) (raw)
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Incubation Period and Reproduction Number for novel coronavirus (COVID-19) infections in India
medRxiv (Cold Spring Harbor Laboratory), 2020
Novel coronavirus (COVID-19) rapidly spread from China to other parts of the world. Knowledge of incubation period and reproduction number is important in controlling any epidemic. The distribution of these parameters helps estimate the epidemic size and transmission potential of the disease. We estimated incubation period and reproduction number of COVID-19 for India utilizing data reported by Ministry of Health and Family Welfare (MoHFW), Government of India (GOI) and data in public domain. The mean incubation period seems to be larger at 6.93 (SD=±5.87, 95% CI: 6.11-7.75). and 95 th percentile estimate for best fit normal distribution is 17.8 days. Weibull distribution, the best fit for the reproduction number estimated pre lockdown reproduction number as 2.6 (95% CI=2.34-2.86) and post lockdown reduced to 1.57 (95% CI=1.3-1.84) implying effectiveness of the epidemic response strategies. The herd immunity is estimated between 36-61% for R 0 of 1.57 and 2.6 respectively. All rights reserved. No reuse allowed without permission.
2020
BackgroundWorld Health organization declared Covid-19 as an outbreak, hence preventive measure like lockdown should be taken to control the spread of infection. This study offers an exhaustive analysis of the reproductive number (R0) in India with major intervention for COVID-19 outbreaks and analysed the lockdown effects on the Covid-19.MethodologyCovid-19 data extracted from Ministry of Health and Family Welfare, Government of India. Then, a novel method implemented in the incidence and Optimum function in desolve package to the data of cumulative daily new confirmed cases for robustly estimating the reproduction number in the R software.ResultAnalysis has been seen that the lockdown was really quite as effective, India has already shown a major steady decline. The growth rate has fluctuated about 20 percent with trend line projections in various lockdown. A comparative analysis gives an idea of decline in value of R0 from 1.73 to 1.08. Annotation plot showing the predicted R0 val...
Issue 4 www.jetir.org (ISSN-2349-5162, 2020
ABSTRACT BACKGROUND: An emergency situation is developed globally due to COVID-19 SARS-CoV-2 virus developed in China, at first reported from its Wuhan province in last week of December’2019. It is declared pandemic by WHO in mid March’2020. As per the record of Government of India and WHO total number of COVID -19 positive cases in India was 8447 with 273 deaths and 1610909 positive with 99690 deaths in world on April’11,2020. The transmission of any infective disease is depended fundamentally on two epidemiological parameters, ie, Exponential Growth Rate and Basic Reproduction Number. MATERIAL AND METHODS: The data of COVID -19 positive cases considered for the present study is covered period from March’11, 2020 to April’ 11, 2020 and obtained from official website of the Government of India. The Basic Reproductive Number was calculated on basis of SEIR (Susceptible-Exposed-Infected-Removed) compartmented model. The formula used for calculation was R0 = 1 + K (Ṯ +Ṱ) + K2 (Ṯ Ṱ); where K represents exponential growth rate. The time intervals are stratified and randomized to neutralize the effect of confounding variables. OBSERVATION: The mean exponential growth/day is calculated as 0.16 with a range of 0.12 to 0.19. For the stratified period the minimum value of exponential growth rate was observed for March’11, 2020 to March’16, 2020 where as maximum value of exponential growth rate was observed from March’31, 2020 to April’05, 2020. The Basic Reproduction Number for COVID -19 is calculated as 1.96 for total period with a range of 1.7 to 2.13. When stratified period is considered, the minimum was observed for March’11, 2020 to March’26, 2020 and maximum was observed for March’31 to April’5, 2020. The cumulative value of COVID -19 positive patients from March’11 to April’11, 2020 and its exponential growth rate was slow up to March’31 and after that the growth curve increased sharply. DISCUSSION: The calculated value of exponential growth and Basic Reproductive Number of COVID-19 in India from March’11 to April’11, 2020 indicate that the problem of epidemics is under control. The exponential growth rate and Basic Reproductive Number is respectively lower than most of the countries of world due to implementation of doctrine of quarantine of exposed group and isolation of symptomatic patients by Government of India. The method is also supported by epidemiological model. CONCLUSION: The exponential growth rate and Basic Reproductive Number of COVID -19 SARS-Cov-2 in India is low in comparison to European countries and America. But 1.96 value of Basic Reproductive Number indicates that the possibility of epidemic has not been ruled out but its possibility exists. Hence the identification of probable exposed clusters, villages and states for COVID- 19 and its primary surveillance at population level and their quarantine and isolation are necessary.
A Review of Reproductive Number ofPandemic Covid-19: Comparative Analysisof R Value
Cohesive Journal of Microbiology & Infectious Disease, 2020
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the most devastating outbreaks witnessed in the last 100 years causing a global health concern.At the beginning of a COVID-19 infection caused by the novel coronavirus (SARS-CoV-2), there is a period of time known as the latency period. In order to epidemic progression many scientists have concentrated on calculating the average number of secondary cases caused by a primary case in the susceptible population, which is referred as basic reproductive number, Ro. In this paper, we have studied the effect of basic reproductive number on the outbreak situation as well as comprehended the transmission pattern of COVID-19 globally. We have analyzed several data of basic reproductive numbers to discuss and finally, capable of exhibiting the prediction of this disease. Finally, comparison of reproductive numbers for several countries are represented graphically for better understanding the present outbreak situation of pandemic, COVID-19.
Epidemiological aspects of covid19 disease in india during nationwide
Background: Covid-19 disease is pandemic in more than 85% of the countries in the world, with about 10 million cases and 0.5 million deaths as on July 2, 2020. In India reporting of the first case was on January 30, 2020, and to prevent rapid community spread of the disease nationwide lockdown phase was imposed from March 25-June 1, 2020. Our objective was to assess various epidemiological measures during the lockdown phase. Methods: We used daily reporting of confirmed cases by the Ministry of Health and Family Welfare, Government of India during the period March 19-June 1, 2020. Using statistical packages STATA and R-packages, we fitted three statistical distributions (Gamma, Weibull and Log-normal) to the daily recorded new cases. We estimated daily incidence rate and death rate per million population, generation time and Basic Reproduction numbers. Results: During the lockdown phase, the daily per cent increase in the cumulative number of cases showed negative exponential growth with 0.022 as an instantaneous rate of decrease. The average incidence rate with a 95% confidence interval (CI) was 1.84 (1.43-2.25). Day specific incidence rate per million (revealed the exponential pattern with 0.069 as the instantaneous rate of increase per day, which accounted for the doubling time of the disease (10 days; 95% CI: 9.25-10.93). Case fatality rate (2.92%; 95% CI: 2.82%-3.02%) and overall death rate was 1.14 (95% CI: 0.87-1.41) per million. were abysmally low. Statistical distribution fitting of new cases found to be satisfactory with Gamma distribution. Basic reproduction numbers 1.83 (95% CI: 1.82-1.83) was less. Conclusion: In India, with a population density of about 450 per Km 2 , the virulent of COVID-19 transmission was interrupted significantly with 70 days lockdown during the early transmission stage. We observed a considerable decline in all the epidemiological indices compared to the corresponding indices recorded during the same period in the severely affected countries.
Estimation of the basic reproduction number of COVID-19 from the incubation period distribution
2021
BackgroundThe estimates of future course of spreading of the SARS-CoV-2 virus are frequently based on Markovian models in which the transitions between the compartments are exponentially distributed. Specifically, the basic reproduction number R0 is also determined from formulae where it is related to the parameters of such models. The observations show that the start of infectivity of an individual appears nearly at the same time as the onset of symptoms, while the distribution of the incubation period is not an exponential.MethodsWe propose a method for estimation of R0 for COVID-19 based on the empirical incubation period distribution and assumed very short infectivity period that lasts only few days around the onset of symptoms. It is tested on daily new cases in six major countries in Europe, in the first wave of epidemic in spring, 2020.ResultsThe calculations show that even if the infectivity starts two days before the onset of symptoms and stops immediately when they appear,...
Characterization of the Second Wave of COVID-19 in India
2021
The second wave of COVID-19, which began around 11 February 2021, has hit India very hard with the daily cases reaching nearly triple the first peak value as on April 19, 2021. The epidemic evolution in India is quite complex due to regional inhomogeneities and the spread of several coronavirus mutants. In this paper, we characterize the virus spread in the ongoing second wave in India and its states until April 19, 2021, and also study the dynamical evolution of the epidemic from the beginning of the outbreak. Variations in the effective reproduction number (Rt) are taken as quantifiable measures of the virus transmissibility. Rt value for every state, including those with large rural populations, has value greater than the self-sustaining threshold of 1. An exponential fit on recent data also shows that the infection rate is much higher than the first wave. Subsequently, characteristics of the COVID-19 spread are analyzed regionwise, by estimating test positivity rates (TPRs) and ...
Joint Estimation of Generation Time and Incubation Period for Coronavirus Disease 2019
The Journal of Infectious Diseases
Background Coronavirus disease 2019 (COVID-19) has caused a heavy disease burden globally. The impact of process and timing of data collection on the accuracy of estimation of key epidemiological distributions are unclear. Because infection times are typically unobserved, there are relatively few estimates of generation time distribution. Methods We developed a statistical framework to jointly estimate generation time and incubation period from human-to-human transmission pairs, accounting for sampling biases. We applied the framework on 80 laboratory-confirmed human-to-human transmission pairs in China. We further inferred the infectiousness profile, serial interval distribution, proportions of presymptomatic transmission, and basic reproduction number (R0) for COVID-19. Results The estimated mean incubation period was 4.8 days (95% confidence interval [CI], 4.1–5.6), and mean generation time was 5.7 days (95% CI, 4.8–6.5). The estimated R0 based on the estimated generation time wa...
Epidemiology and Health, 2020
Coronavirus disease 2019 (COVID-19), which causes severe respiratory illness, has become a pandemic. The World Health Organization has declared it a public health crisis of international concern. We developed a susceptible, exposed, infected, recovered (SEIR) model for COVID-19 to show the importance of estimating the reproduction number (R 0). This work is focused on predicting the COVID-19 outbreak in its early stage in India based on an estimation of R 0. The developed model will help policymakers to take active measures prior to the further spread of COVID-19. Data on daily newly infected cases in India from March 2, 2020 to April 2, 2020 were to estimate R 0 using the earlyR package. The maximum-likelihood approach was used to analyze the distribution of R 0 values, and the bootstrap strategy was applied for resampling to identify the most likely R 0 value. We estimated the median value of R 0 to be 1.471 (95% confidence interval [CI], 1.351 to 1.592) and predicted that the new case count may reach 39,382 (95% CI, 34,300 to 47,351) in 30 days.