![]() The novel coronavirus disease 2019 (Also known as COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global concern and has become a significant health problem since the number of infected cases and affected countries has escalated rapidly. In late December 2019, China reported an outbreak of viral pneumonia in Wuhan, Hubei Province, China, which spread rapidly to other areas. HCWs are among the highest groups at risk of infection during the COVID-19 pandemic therefore, evaluating infection rates and associated features is necessary to improve and adjust protective measures of these vulnerable, yet highly essential group. Regarding safety precautions, 1.6% didn't wear masks and 18.7% didn't use gloves in work environments. Furthermore, 10.3% of the cases reported transmitting the infection to family and friends. Although 5.5% were admitted to hospitals, there were no reports of ICU admission. Also, 35.5% of the patients were asymptomatic and the most frequent clinical features among symptomatic patients were myalgia (46%) and cough (45.5%). Also, the highest rate of infection was in the emergency rooms (30.6%). The majority of infected cases were among nurses (51.3%), while the most case infection rate (CIR) was among physicians (27 positive cases out of 842 performed test (3.2%)). Our data demonstrated a rate of 5.62% (273 out of 4854 cases) infection among HCW, with a mean age of 35 years and a dominance of female cases (146 cases: 53.5%). Methodsĭemographic and clinical data regarding infected cases among HCWs of Fars, Iran with positive SARS‐CoV‐2 PCR tests were obtained from 10th March to 17th May 2020. It is imperative to ensure the safety of health-care workers (HCWs) not only to safeguard continuous patient care but also to ensure they do not transmit the virus, therefore evaluation of infection rates in these groups are indicated. However, studies on the infection status of medical personnel are still lacking. With the novel coronavirus pandemic, the impact on the healthcare system and workers cannot be overlooked. related methods are risk (prospective), relative risk meta-analysis, risk difference meta-analysis and proportionsĬopyright © 2000-2022 StatsDirect Limited, all rights reserved.prone to the bias of change in methods over time.prone to attrition bias (compensate by using person-time methods).may uncover unanticipated associations with outcome.yields true incidence rates and relative risks.The following notes relate cohort to case-control studies: ![]() related methods are risk (retrospective), chi-square 2 by 2 test, Fisher's exact test, exact confidence interval for odds ratio, odds ratio meta-analysis and conditional logistic regression.Ĭohort studies are usually but not exclusively prospective, the opposite is true for case-control studies.controls are selected on the basis of not having the outcome.The following notes relate case-control to cohort studies: Prospective investigation is required to make precise estimates of either the incidence of an outcome or the relative risk of an outcome based on exposure.Ĭase-Control studies are usually but not exclusively retrospective, the opposite is true for cohort studies. You should take special care to avoid sources of bias and confounding in retrospective studies. ![]() In retrospective studies the odds ratio provides an estimate of relative risk. If the outcome of interest is uncommon, however, the size of prospective investigation required to estimate relative risk is often too large to be feasible. For this reason, retrospective investigations are often criticised. Most sources of error due to confounding and bias are more common in retrospective studies than in prospective studies. Many valuable case-control studies, such as Lane and Claypon's 1926 investigation of risk factors for breast cancer, were retrospective investigations. Prospective studies usually have fewer potential sources of bias and confounding than retrospective studies.Ī retrospective study looks backwards and examines exposures to suspected risk or protection factors in relation to an outcome that is established at the start of the study. All efforts should be made to avoid sources of bias such as the loss of individuals to follow up during the study. ![]() The outcome of interest should be common otherwise, the number of outcomes observed will be too small to be statistically meaningful (indistinguishable from those that may have arisen by chance). The study usually involves taking a cohort of subjects and watching them over a long period. A prospective study watches for outcomes, such as the development of a disease, during the study period and relates this to other factors such as suspected risk or protection factor(s).
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