**1. Introduction**

COVID 19 continues to threaten health of the humankind [1, 2]. COVID-19 is transmitted by close contact and droplets among people. However, airborne contamination may be possible under certain conditions and environments in which procedures or supportive treatments that produce aerosols are performed [3]. Those who are most at risk of getting this disease are those who have contact with the patient or those who provides care for them. Therefore, the protection of HCWs is considered as one of the top priorities [4–6].

In all countries with COVID-19 pandemic, the caught unaware staff was effective in the transmission, since the transmission dynamics of the COVID-19 virus was not fully known at the onset of the outbreak [7, 8]. With the reporting of the first cases, the protective equipment has been widespread used. The initial case diagnosis in our country were made with guides in the form of a history of international contact and clinical definitions [8, 9]. Recently, as of September 2020, 601 HCWs were positive for the COVID-19 test during the onset of the outbreak, and then it was reported as 7,428 health workers had been infected, which is around 6.5 percent of the total number of cases [10].

The cases reported by our HCWs in the first week concurrently with the general course of the country, there was no history of traveling abroad and there had not been aware of suspected contacts. The fact that there were 27 HCWs in the first month and the first two index cases and 4 HCWs in the second month supported this outcome. During the epidemy, HCWs are under tremendous stress. Working with personal protective equipment (PPE) and performing specific procedures are cumbersome and were not convenient [11, 12]. Despite all these difficulties it was necessity to use highly protective respirators such as N95 or P2/FFP2/FFP3 for HCWs. Employees' occupational health and safety should be given high priority and a uniform policy should be applied to use personal protective equipment to prevent infection [7].

We aimed to identify the clinical features of 27 HCWs who were in contact with the first two index cases infected with COVID-19 and compare them with previous studies.

#### **2. Material and methods**

After the first index cases were diagnosed, filiation and evaluation of concurrent symptomatic applicants were performed at the Infectious Diseases clinic. Retrospectively, clinical findings were classified as severe (1–14 days), moderate (1–7 days), and mild (no hospitalization days), considering the duration of symptoms, length of hospital stay, and treatment practices. Patients with possible SARS-CoV-2 infection were examined via real-time RT-PCR and next-generation sequencing laboratory techniques. This study was approved by the Ministry of Health of Turkey, Scientific Research Ethics Committee No: Ayse Erturk-2020-05- 11T12\_27\_08 and local ethics committee RTEU Faculty of Medicine Rize/Turkey – No: 2020/82.

#### **2.1 Statistical analysis**

SPSS 17.0 (Chicago Inc., 2008) program was used in the analysis. Categorical variables were expressed in terms of frequency (n) and percent (%) and in arithmetic mean, standard deviation, median, minimum and maximum values. While the Student t-test was used for comparison of continuous distributors with *Demographic, Clinical and Radiological Features of Healthcare Workers and Two Index Cases… DOI: http://dx.doi.org/10.5772/intechopen.99148*

normal distribution, those without normal distribution were analyzed with the Mann–Whitney U test. Pearson-χ2 and Fisher's exact tests were used for categorical variables. Paired-t test and Wilcoxon signed rank tests were used to compare the first and second levels of laboratory measurement parameters. P < 0.05 was accepted as the level of significance.
