Table of Contents
Study design and setting, and study population
This is a cross-sectional study conducted in the hospitals located of Lahj and AL-Dhalea governorates in the southern part of Yemen in the period from June 2022 to September 2022 (Map of Yemen identifying the study areas). Lahj governorate, with a population of nearly 900,000 people, is located northwest of major southern city of Aden and is divided into 15 administrative districts with the city of Al-Hawtah as its capital. Al-Dhalea governorate, with a population of almost 500,000 people, is located in the southern-central part of Yemen with a population of nearly 500,000 people and encompasses nine administrative districts, with Al-Dhalea as its capital, [26] as seen in Fig. 1 [27].
Map of Yemen identifying the areas of the Lahej and Aldalea Governorate
The study population included a range of HCWs, such as doctors, nurses, x-ray physicians, dentists, laboratory personnel, pharmacists, respiratory therapists, and nutritionists, in addition to auxiliary HCWs such as clerks, housekeeping staff, laundry personnel, and social workers. Those who didn't agree to participate in the study and did not fill in the questionnaire were excluded with around 12 out of the total 416 (2.9%). However, participants were gathered into four categories according to the importance of the participants and the level of contact with patients complaining of COVID-19 infection such as physicians, nurses, allied health workers who involved in giving healthcare services distinct from medicine or nursing [28], and finally those categorized as support services, as people responsible for providing and maintaining a sanitary and therapeutic environment in which health care can be appropriately delivered to individuals [29]. Therefore, allied health workers included those working in the x-ray department, laboratory, and pharmacy accounting around 92 workers (22.8%). While those working in supporting services section such as cleaning and laundry personnel, maintenance, admission/reception clerks, patient transporters social workers, and housekeeping with a total of 58 participants (14.4%).
To recruit the participants, the research team obtained permission from the hospital administration in each governorate to conduct the study [30], as well as the work was approved by the Ethics Research Committee (ERC) of the Faculty of Medicine and Health Sciences, University of Aden (REC-#119–2022). An informed consent was given to the participants and the study team provided a brief overview of the study objectives to potential participants and requested their voluntary participation. Those who agreed to participate were asked to complete a self-administered questionnaire and provide a blood sample for serological testing. The questionnaire collected information on demographic characteristics, work-related factors, COVID-19-related symptoms, and exposure to COVID-19 patients or suspected cases.
Sampling and sampling technique
The prevalence of anti-SARS-CoV-2 antibodies among healthcare workers in Yemen is not well understood, so a large sample size was needed to estimate it accurately. Based on an assumed prevalence rate of 50%, a 95% confidence interval, and a 5% margin of error, a sample size of 384 was calculated using Daniel’s equation [31]. To account for possible missing data or participant dropouts, an additional 5% of the sample size was added, resulting in a final sample size of 404 HCWs.
To ensure a representative sample, we used the Probability Proportional to Size (PPS) sampling technique to enroll participants from both Lahj and Al-Dhalea governorates proportionally. Of the HCWs who presented in the hospitals during the sampling period, 267 (66%) from Lahj and 137 (34%) from Al-Dhalea were enrolled in the sample and a convenience sampling method was used to complete the required sample from each hospital and governorate.
Data collection
The study used a self-reported questionnaire based on the WHO protocol for COVID-19 infection among HCWs in a healthcare setting [4]. The HCWs completed the questionnaire in front of the investigator for any assistance needed by the participant and before the collection of the blood sample (8–12 min average). The questionnaire comprised of five domains, including demographic data, data related to exposure to COVID-19, COVID-19 symptoms and PCR confirmed or suspected infection, comorbidities, IPC measures, and COVID-19 vaccination. The first domain encompassed the demographic data including age, sex, healthcare setting, work experience, and occupation category. The second domain included data related to exposures to COVID-19 and these consisted of the frequency of exposure, time of occurrence, and the setting as a source of infection. The third domain comprised COVID-19 symptoms and PCR confirmed or suspected infection. The fourth domain consisted of data of comorbidities encompassing asthma, heart disease, hypertension, kidney disease, diabetes mellitus, and immune deficiency. The fifth domain encompassed data on IPC measures which included follow IPC standard precautions, following 5 recommended moments, use alcohol-based hand rub or soap, wear PPE with the COVID-19 patient, PPE available in sufficient quantity, and attended IPC training. In addition, this domain includes variables related to COVID-19 vaccination which included receiving of vaccine, acceptance, or hesitancy to receive the vaccine.
The questionnaire was originally in English and was translated into Arabic for ease of understanding and back to English to secure the consistency of the questions.
Pre-testing
Reliability test was undertaken among 30 HCWs in analogy to the site of the study to ensured that the questionnaire was easy to use and acceptable by the interviewees. Reliability also was considered by reaching a Cronbach alpha of not less than 0.73 of the completed questionnaires which indicates that the overall response values for each participant across a set of questions are consistent.
Laboratory investigation
A volume of five ml venepuncture blood sample was drawn from each participant via the venipuncture technique with universal precautions conducted by the concerned technician. Blood samples were collected in EDTA tubes and stored at 4 °C and transferred on the same day to the hospital laboratory for analysis. The samples were labelled with the department name, name of the participant, date, and identification number [4]. Sera were tested for anti-SARS-CoV-2 using Elecsys Anti-SARS-CoV-2 Qualitative assay for use on the Cobas, Roche Diagnostics GmbH, electrochemiluminescence immunoassay (ECLIA) according to the instructions of the manufacturer. The assay has a sensitivity of 99.81% (CI 95%: 99.6–99.9%) and a specificity of 99.5% (CI 95%: 98.63–99.85%) and is certified by WHO [32, 33]. The assay provides a qualitative detection of all antibody classes (including IgG) to SARS-CoV-2 in human serum and plasma and is intended for use as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, for recent or prior infection. It can detect the presence of anti-SARS-CoV-2 antibodies in serum within days to weeks following acute infection [34, 35]. Sera with a Cut off Index (COI; signal sample/cut-off, COI) ≥ 1.0 were considered positive, those with a COI < 1.0 were considered negative.
Data management and statistical analysis
The data was coded and entered into SPSS version 23 for analysis. Descriptive statistics, including mean and standard deviation, were used to summarize continuous variables, while absolute and relative frequencies were used for categorical variables. The Chi-square test was used to examine the association between the dependent and the independents variables. A P- of < 0.05 was considered statistically significant.
