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1.
Economic Alternatives ; 29(1):5-25, 2023.
Article in English | Scopus | ID: covidwho-2299605

ABSTRACT

This contribution aims to discuss an original survey methodology, conceived in lockdown conditions, when face to face interviewing was prohibited and economic and sociological research faced obstacles in obtaining empirical data. An original pseudo-longitudinal Covid-CAWI is conducted in two fully harmonized waves. The basic methodological principles are elucidated along with limitations and advantages within the context of anti-epidemic measures and lockdowns in Bulgaria. The article elaborates the steps of data cleaning, conducted as an essential pre-processing step to high level of data quality. Special focus is devoted to posterior data optimization, using post-stratification adjustments. A comparison between weighted and unweighted data on economic effects is analysed. The paper contributes to the scientific debate on methodology insofar as online surveys become the one and only research opportunity for quantitative research in a crisis situation. The presented analysis of subsequent optimization procedures in Internet studies aims to open a discussion, especially in the context of socioeconomic research in a crisis situation where there are physical distance constraints. The data from the Covid-CAWI survey will be available for open access, so all interested in research may analyse the effects of the pandemic on social and economic life and debate on survey methodology. © 2023, University of National and World Economy. All rights reserved.

2.
Biostatistics ; 2023 Mar 06.
Article in English | MEDLINE | ID: covidwho-2281852

ABSTRACT

Naive estimates of incidence and infection fatality rates (IFR) of coronavirus disease 2019 suffer from a variety of biases, many of which relate to preferential testing. This has motivated epidemiologists from around the globe to conduct serosurveys that measure the immunity of individuals by testing for the presence of SARS-CoV-2 antibodies in the blood. These quantitative measures (titer values) are then used as a proxy for previous or current infection. However, statistical methods that use this data to its full potential have yet to be developed. Previous researchers have discretized these continuous values, discarding potentially useful information. In this article, we demonstrate how multivariate mixture models can be used in combination with post-stratification to estimate cumulative incidence and IFR in an approximate Bayesian framework without discretization. In doing so, we account for uncertainty from both the estimated number of infections and incomplete deaths data to provide estimates of IFR. This method is demonstrated using data from the Action to Beat Coronavirus erosurvey in Canada.

3.
Infect Dis Model ; 8(1): 228-239, 2023 Mar.
Article in English | MEDLINE | ID: covidwho-2235217

ABSTRACT

Controlling the COVID-19 outbreak remains a challenge for Cameroon, as it is for many other countries worldwide. The number of confirmed cases reported by health authorities in Cameroon is based on observational data, which is not nationally representative. The actual extent of the outbreak from the time when the first case was reported in the country to now remains unclear. This study aimed to estimate and model the actual trend in the number of COVID -19 new infections in Cameroon from March 05, 2020 to May 31, 2021 based on an observed disaggregated dataset. We used a large disaggregated dataset, and multilevel regression and poststratification model was applied prospectively for COVID-19 cases trend estimation in Cameroon from March 05, 2020 to May 31, 2021. Subsequently, seasonal autoregressive integrated moving average (SARIMA) modeling was used for forecasting purposes. Based on the prospective MRP modeling findings, a total of about 7450935 (30%) of COVID-19 cases was estimated from March 05, 2020 to May 31, 2021 in Cameroon. Generally, the reported number of COVID-19 infection cases in Cameroon during this period underestimated the estimated actual number by about 94 times. The forecasting indicated a succession of two waves of the outbreak in the next two years following May 31, 2021. If no action is taken, there could be many waves of the outbreak in the future. To avoid such situations which could be a threat to global health, public health authorities should effectively monitor compliance with preventive measures in the population and implement strategies to increase vaccination coverage in the population.

4.
Sci Total Environ ; 764: 142799, 2021 Apr 10.
Article in English | MEDLINE | ID: covidwho-1065576

ABSTRACT

During the Covid-19 pandemic in Italy, official data are collected with medical swabs following a pure convenience criterion which, at least in an early phase, has privileged the exam of patients showing evident symptoms. However, there are evidences of a very high proportion of asymptomatic patients. In this situation, in order to estimate the real number of infected (and to estimate the lethality rate), it should be necessary to run a properly designed sample survey through which it would be possible to calculate the probability of inclusion and hence draw sound probabilistic inference. Unfortunately, the survey run by the Italian Statistical Institute encountered many field difficulties. Some researchers proposed estimates of the total prevalence based on various approaches, including epidemiologic models, time series and the analysis of data collected in countries that faced the epidemic in earlier times. In this paper, we propose to estimate the prevalence of Covid-19 in Italy by reweighting the available official data published by the Istituto Superiore di Sanità so as to obtain a more representative sample of the Italian population. Reweighting is a procedure commonly used to artificially modify the sample composition so as to obtain a distribution which is more similar to the population. In this paper, we will use post-stratification of the official data, in order to derive the weights necessary for reweighting the sample results, using age and gender as post-stratification variables, thus obtaining more reliable estimation of prevalence and lethality. Specifically, for Italy, we obtain a prevalence of 9%. The proposed methodology represents a reasonable approximation while waiting for more reliable data obtained with a properly designed national sample survey and that it could be further improved if more data were made available.


Subject(s)
COVID-19 , Adult , Female , Humans , Italy/epidemiology , Male , Pandemics , Prevalence , SARS-CoV-2
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