Potential Risk Factors for COVID-19 Infection among Healthcare Workers in a Tertiary Care Centre, Kerala, India
Correspondence Address :
Asha Joan Murali,
Thuruthy P.O, Kottayam, Kerala, India.
Introduction: Understanding the virus transmission patterns and routes of transmission among Healthcare Workers (HCWs) is limiting the amplification events in health care facilities.
Aim: To estimate the secondary infection rate and to describe the clinical presentation of infection and the risk factors for infection among healthcare worker contacts of Coronavirus Disease-2019 (COVID-19) cases.
Materials and Methods: A descriptive cross-sectional study was conducted from June 2020 to July 2021, at a tertiary care centre, in central Kerala, India, among all the healthcare workers with exposure to a COVID-19 confirmed cases within the institution, between 15 July 2020 to 15 August 2020. Data including demographic details, information on contact and possible exposure with the COVID-19 infected patient was obtained using a questionnaire adapted from the World Health Organisation (WHO) questionnaire. Data was entered into Microsoft Excel and analysed using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) version 22.0.
Results: A total of 433 healthcare workers (382 females and 51 males, mean age: 34.33±10.79 years) were found to be exposed to COVID-19 confirmed cases in the institution. The 21.1% of the healthcare worker contacts were exposed while working in non-COVID Intensive Care Unit (ICU) setting. Out of the 433 HCWs who were exposed to COVID-19 patients, 9 tested positive for COVID-19 (secondary infection rate was 2.07% with a Confidence Interval (CI) of 0.7-3.4%). All 9 of the positive HCWs were females, of which 88.89% were symptomatic.
Conclusion: Healthcare workers are at risk of transmission of COVID-19 while providing care, hence further explorative studies, including serologic studies are recommended to further understand the epidemiology.
Coronavirus disease 2019, Healthcare setting, Kerala, Secondary infection rate
Coronavirus Disease-2019 (COVID-19) is a novel viral disease with over 182,319,261 confirmed cases worldwide and the total global deaths has surpassed 3,954,324 (1) by July 2021. Knowledge regarding the epidemiology of the disease and clinical presentation has been evolving since the initial identification of the virus.
Other coronaviruses which have caused pandemics like the Middle East respiratory syndrome-Coronavirus (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS) are known to have caused outbreaks in health care settings (2). Similarly, SARS CoV-2 also has the potential for grave impact on healthcare settings (3). Systematic reviews have reported SARS CoV-2 test positivity among healthcare workers as high as 51% (4). This high incidence is alarming as healthcare workers are not only critical for the clinical management of patients, but they are also important links in the chain of transmission (4). They are both vulnerable to infection while providing care, due to their close interaction with the patients, and they are at the highest risk of transmission to others both within the institution and outside the institution (5),(6). Moreover, infection among health care workers will lead to depletion of the work force and in turn have an adverse effect on patient care (6).
Understanding the virus transmission patterns and routes of transmission among health care workers will be an important step in limiting the amplification events in health care facilities (2). To better understand the transmission dynamics, and an overall risk of infection among healthcare worker contacts, secondary infection rate which is a measure of the frequency of new cases of COVID-19 among the contacts of a confirmed case in a defined period may be explored (2). Since the studies regarding same are lesser in number (7),(8),(9) with pretty limitations, hence this study was conducted in a tertiary care setting, to estimate the secondary infection rate and to describe the clinical presentation of infection and the risk factors for infection among the healthcare worker contacts of COVID-19 cases.
This cross-sectional descriptive study was conducted at a tertiary care centre, in the central part of Kerala, after obtaining approval from the Institutional Review Board (No:16/2020 dated 28.06.2020) between June 2020 and July 2021. All the healthcare workers who were involved in care of COVID-19 confirmed cases between 15th of July and 15th of August 2020 were enlisted. From the list, of all those involved in the care, those who disclosed a history of exposure to COVID-19 positive patients, either due to breach of Personal Protective Equipment (PPE), or because the status of the patient was unknown at the time of exposure was contacted through telephone and information was gathered. After assessment, they were classified as those with high-risk exposure and low risk exposure. A total of 433 healthcare workers at Government Medical College, Kottayam, Kerala, India, were found to be exposed to 15 COVID-19 confirmed cases in the institution.
Inclusion criteria: All healthcare workers with exposure to a COVID-19 confirmed case, including those with direct exposure and those with exposure to the patient’s blood and body fluids, and to contaminated materials or devices and equipment linked to the patient.
Exclusion criteria: Healthcare workers who have been exposed to another implicated source of confirmed COVID-19, for example a COVID-19 positive case among his/her household/close contacts/ occupational contacts working in the same or outside institutions, or any other outside source were excluded from the study.
Health care worker was defined as all staff in the healthcare facility involved in the provision of care for a coronavirus infected patient, including those who have been present in the same area as the patient, as well as those who may not have provided direct care to the patient, but who have had contact with the patient’s body fluids, potentially contaminated items, or environmental surfaces. This includes health care professionals, allied health workers, auxiliary health workers (e.g., cleaning and laundry personnel, x-ray physicians and technicians, clerks, phlebotomists, respiratory therapist, social workers, physical therapists, lab personnel, cleaners, admission/reception clerks, patient transporters etc) (2).
Secondary Infection rate was defined as the proportion of healthcare worker contacts of a primary case who tested positive for Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) by Reverse Transcriptase Polymerase Chain Reaction (RTPCR) or rapid antigen test (2).
Secondary infection rate= Number of healthcare workers confirmed to have COVID-19 / Total number of healthcare workers enrolled as contacts of the case
High risk exposure: The details of exposure among the healthcare worker contacts of COVID-19 confirmed cases, including the duration of exposure, history of close contact and use of personal protective equipment were assessed and the risk of exposure was classified as ‘high-risk exposure’ in cases where there was close contact for a duration of more than 15 minutes and appropriate personal protective equipment was not used (10),(11). Otherwise classified as, low risk exposure.
Once a case of COVID-19 infection was identified in the institution, all healthcare workers with any exposure to COVID-19 patient was listed. This was done in consultation with supervisors and colleagues, duty rosters and the medical file of the patient to understand all the areas of the healthcare facility the patient has visited. From the list, of all those involved in the care, those who disclosed a history of exposure to COVID-19 positive patients, either due to breach of PPE, or because the status of the patient was unknown at the time of exposure was contacted through telephone and information was gathered. Telephonic interview was conducted, and the purpose of the investigation was explained to all known healthcare worker contacts. Data including demographic details, information on contact and possible exposure with the COVID-19 infected patient as well as laboratory results of respiratory specimen was obtained using a questionnaire [Annexure-1] adapted from WHO questionnaire for the assessment of potential risk factors for 2019-novel coronavirus infection among healthcare workers in a health care setting (2). and was translated into the native language Malayalam and back translated. The content validation was done by subject experts. Data was collected within a week of exposure to avoid recall bias. After assessment, they were classified as those with high-risk exposure and low-risk exposure.
Data was entered using Microsoft Excel and analysed using statistical package for social sciences (SPSS) version 22.0. The variables were summarized as mean with standard deviation and frequency with percentage.
The mean age of the health care worker contacts was 34.33±10.79 years, ranging between 19 and 61 years. Among them 88.22% were females (n=382) and 11.78% were males (n=51). The department wise distribution and category of health care workers is depicted (Table/Fig 1). On enquiring regarding the adherence to infection prevention and control measures, invariably all the healthcare staff reported that they adhered to infection prevention control measures while caring for patients routinely (Table/Fig 2). It was observed that 21.1% of the healthcare worker (n=91) were exposed while working in non-COVID-Intensive Care Unit (ICU) setting and 78.9% (n=342) were exposed while working in non-COVID wards.
On exploring the details of exposure, 81.9% of the healthcare workers (n=355) reported close contact with a COVID-19 patient, 45.7% (n=198) reported direct contact with the patient’s materials like personal belongings, linen and medical equipment that the patient may have had contact with) and 89.3% (n=387) reported direct contact with the surfaces around the patient (bed, bathroom, ward corridor, patient table, bedside table, dining table, medical gas panel etc) (Table/Fig 3).
After assessing the details of exposure, 28.4% (n=123) were found to have high risk exposure to COVID-19 confirmed cases (close contact of duration above 15 minutes without wearing PPE appropriate to the setting).
(Table/Fig 4), (Table/Fig 5) gives details of the distribution of HCWs according to the type of patient’s material that they had direct contact with and the type of surfaces around the patient that they had direct contact with. Details regarding symptom development in the period since patient admission and pre-existing co-morbidities of the healthcare workers were also assessed as part of the WHO questionnaire (Table/Fig 6).
Secondary infection rate: Out of the 433 HCWs who were exposed to COVID-19 patients, 9 tested positive for COVID-19. The secondary infection rate was 2.07% (CI-0.7-3.4%).
All 9 of the positive HCWs were females with a mean age 31 years (SD of 10.72 years). All were exposed while providing care in a ward setting, to COVID-19 cases whose status was unknown at the time of exposure. On evaluating the details, it was found that all 9 had high risk exposure to the COVID-19 case, and in 7 (77.7%) of them, HCW was exposed to multiple COVID-19 patients. A total of 6 of the healthcare workers (66.6%) were not using PPE appropriate for the setting at the time of exposure (10). Three HCWs were using PPE appropriate to the setting but reported breach of PPE (2 reported that they were wearing N95 masks in ward, but had removed the mask while attending phone calls, 1 reported that her mask was wet).
A total of 8 positive HCW contacts i.e., 88.89% were symptomatic - fever reported by 3, sore throat by 2, cough by 2, nasal symptoms by 2 and abdominal symptoms by 1. Except 1 (11.1%) who had history of bronchial asthma, no other positive HCW contacts gave history of co-morbidities. None had ICU admission.
On exploring the secondary infection rate according to the department of work [Table/Fig 7], it was seen that 2 among the 20 HCW contacts (Secondary infection rate of 10 %) in the Department of Paediatrics and 7 among the 205 HCWs (secondary infection rate of 3.4 %) in the Department of Obstetrics and Gynaecology became COVID-19 positive.
On assessing the category of staff, secondary infection rate was highest among technicians, security staff etc (Table/Fig 8).
In the present study, 433 healthcare workers were found to be exposed to COVID-19 confirmed patients in the institution during the study period. They were exposed while providing care in a non-COVID setting, where patient status was unknown at the time of exposure or had history of use of breach of PPE or was not using PPE appropriate for the setting (10). This may be explained by the fact that, as recommended in the WHO assessment protocol (2), the study was conducted within the early phases of the epidemic, before widespread transmission or nosocomial outbreaks occurred, when stringent infection prevention and control measures were yet to be instigated.
On assessing the details of adherence to infection prevention and control measures by healthcare workers routinely, invariably all the healthcare staff reported that they adhered to all the routine infection prevention control measures. This data may be biased, especially in the current COVID-19 scenario, healthcare workers may not be ready to commit to the fact that they do not adhere to COVID-19 practice routinely.
Out of the 433 healthcare workers who were exposed, 9 were found to be COVID positive. Those COVID positive healthcare workers, who had another implicated source of COVID-19 infection like a positive family member, a colleague, or a source from a different setting, were excluded from the study.
In the present study, the most exposed category of healthcare workers was nursing staff 176 (40.6%). Nursing staff being exposed the most may be explained by the longer duration that they involved in direct patient care, bedside tasks, drug administration etc as well as being the first line of response in case of any patient complaints (5). Whereas the secondary infection rate among nursing staff in the present study was only 0.57%. Contrasting finding was seen in the study by Alajmi J et al., (6), where the highest number of infected healthcare workers were nurses and midwives (33.2%), and Gómez-Ochoa SA et al., (5) also reported upto 48% of infection among nursing staff.
The current study revealed that the exposure of healthcare workers occurred in a non-COVID setting (21.1% in non-COVID ICU and 78.9% in non-COVID wards). Alajmi J et al., also reported a very similar picture where 95% of the infected healthcare workers reported acquiring the virus while working in a non-COVID-designated setting (6). This may be possibly because of unknown status of the infected, lower adherence to prescribed personal protective equipment, lesser observance of infection prevention and control measures in non-COVID settings as compared to COVID setting, especially in the initial phase of the pandemic (6).
In the present study, secondary infection rate among healthcare worker contacts was 2.07 % (0.7-3.4%). Similar to these findings, Huang YT et al., reported secondary attack rate in a hospital setting as 1.56% with CI of 0.73-2.93% (12). Most of the available literature explores the prevalence of SARS-CoV-2 among health care workers, and Indian studies have reported up to 11% prevalence among healthcare workers (Table/Fig 9) (6),(8),(9),(12),(13).
The mean age of the infected healthcare workers in the current study was 31 years (SD of 10.72 years) and all were females. Similarly studies by Mandana G et al., (4) Jeremias A et al., (14) and Sabetian G et al., (9) reported a higher female proportion of 78.6%, 70% and 53.5% respectively, but a higher mean age of 38.37 years, 42.8 years and 35 years respectively. It could be due to the socio-demographic difference in the sample.
The current study showed that 8 (88.89%) of the infected health care workers were symptomatic and the most common symptom was fever. These findings are in line with the findings of Mahajan NN et al., (8) who reported that 85% of the infected health care workers were symptomatic and Nguyen LH et al., (13) who reported that 93.5% as symptomatic. Also fever was documented as the most prevalent symptom in studies by Jeremias A et al., (14) and Ran L et al., (15).
In the present study, all the positive health care workers had high risk exposure and 7 (77.7%) had multiple exposure, i.e., either was exposed multiple times or to multiple confirmed cases. These figures were higher than the findings of Mansoor S et al., who reported 40% multiple exposure and 20% of the high risk exposure health care workers tested positive in his study (16). This difference could be explained by the fact that there was a positive cluster of mothers and babies in the Obstetrics and Gynaecology (OBG) Department and Neonatal unit during the period that this study was conducted, as opposed to scattered cases in other departments. (Table/Fig 7) 205 HCWs in the department of OBG were exposed and 7 were positive, and in the department of Paediatrics 20 of the healthcare workers were exposed and 2 were positive. Hence the healthcare workers in these departments were exposed to multiple cases and since the infection status of the patients were unknown at the time of exposure, the staff were exposed multiple times to the same case while providing care. There could have been asymptomatic or pre-symptomatic transmission of SARS-CoV-2 virus through respiratory droplets (17).
Some healthcare workers included in the study might have contracted the infection from an unknown asymptomatic source outside the institution and not necessarily from a patient within the institution. Not being able to exclude them was a drawback of the study.
The present study concluded that the secondary infection rate among healthcare workers from COVID-19 patients was 2.07%. High risk exposure and exposure in non-COVID setting and not using PPE appropriate for the setting was seen among the infected. More seroepidemiological studies and studies including more than one centre are recommended to validate the results of this study.
Date of Submission: Nov 02, 2021
Date of Peer Review: Jan 11, 2022
Date of Acceptance: Mar 24, 2022
Date of Publishing: Jun 01, 2022
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. NA
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