Key words
SARS-CoV-2 antibodies - seroprevalence - risk factors - prevention - radiological
staff
Introduction
With millions of people infected globally and a severe disease course in some cases,
coronavirus disease 2019 (COVID-19) caused by SARS coronavirus 2 (SARS-CoV-2) has
been overloading the health care systems of many countries since the end of 2019[1]. Protecting patients and health care workers (HCWs) against infection with the virus
during treatment was and continues to be a difficult task during the ongoing pandemic.
Radiology personnel are on the front lines of the response to the COVID-19 pandemic
and are at increased risk of infection due to their significant contact with infected
and potentially infectious patients in the course of performing their occupational
duties. The virus can be transmitted by patients as well as from HCW to HCW and via
contact surfaces or aerosols [2].
The seroprevalence of antibodies to SARS-CoV-2 allows conclusions regarding a prior
COVID-19 infection [3]
[4] and makes it possible to identify risk areas within the diagnostic routine. As a
result, workflows and precautionary measures can be optimized and transmission within
the hospital can be minimized [5].
Like physicians and HCWs working in wards, radiology employees in the clinical routine
have direct contact with infected patients. However, in contrast to HCWs providing
inpatient care, direct patient contact of radiology staff can be determined relatively
exactly even retrospectively based on the documented radiological examinations of
COVID-19-positive patients.
To evaluate the risk to radiology staff (administrative staff, technicians, physicians)
posed by direct contact with COVID-19-positive patients, we evaluated the data from
two hospital groups in regions of Germany affected to varying degrees by the COVID-19
pandemic. The hospitals tested a majority of their personnel multiple times for the
seroprevalence of antibodies to SARS-COV-2 and analyzed the data in relation to individual
work areas and departments in the hospital. The data from one hospital group in the
region of the northern Upper Palatinate (Southeast Germany) with the highest infection
rate (up to 1570 cases/100 000 inhabitants) was evaluated. The radiology department
in a region in northeastern Germany (Brandenburg) with a lower infection rate (65/100 000)
was examined as a control group. The goal of the study was to evaluate the probable
prior infection of radiology staff during the first wave of the COVID pandemic and
to compare the data to direct patient contact corresponding to radiological examinations
of COVID-19-positive patients.
Materials and Methods
Study locations
We analyzed the antibody status and clinical symptoms of COVID-19 disease of radiology
personnel as part of an ongoing study of hospital personnel at two locations in Germany
affected to varying degrees by the COVID-19 pandemic.
Study region – hospital A (southeast Germany) – high prevalence
Hospital A (774 beds at 2 locations) represents the situation in a high-risk region
for COVID-19. The hospital provides care for approximately 280 000 inhabitants of
a region of Germany in a rural area in northeast Bavaria with a high prevalence of
COVID-19 between March and July 2020 [6]. This region includes the county Tirschenreuth (1570 cases/100 000 inhabitants)
as well as the counties Wunsiedel (909/100 000) and Neustadt/Waldnaab (860/100 000),
which were ranked 3 and 4 in the prevalence statistics of the RKI (Robert Koch Institute)
in July 2020. The city Weiden as the site of the main hospital (796/100 000) was ranked
7 Germany-wide in July 2020 prior to the first German coronavirus hotspot in Heinsberg
(776/100 000) [7]. In the health care facilities of this region, more than 1450 patients with suspected
COVID-19 were treated on an inpatient basis between March and July 2020. SARS-CoV-2
infection was confirmed via PCR in 594 of these patients ([Table 1]).
Table 1
Aggregation of key data describing the two different regions in Germany for hospital
A (high prevalence) and hospital B (low prevalence) regarding the COVID-19 pandemic
during the study period from March to July 2020.
|
hospital A
Southeast Germany
high prevalence
|
hospital B
Northeast Germany
low prevalence
|
|
state
|
Bavaria
|
Brandenburg
|
|
number of people receiving care (n)
|
280 000
|
177 000
|
|
COVID-19 cases/100 000 in the region serviced by the hospital
|
776–1570
|
65
|
|
PCR-confirmed COVID-19 cases at the hospital
|
594
|
50
|
Study region – hospital B (northeast Germany) – low prevalence
Hospital B is a health care provider for approximately 177 000 inhabitants in northeastern
Germany (Brandenburg). Only 65 positive COVID-19 cases were identified in the study
period up to July 2020 at the control hospital. From March to July, only 50 patients
with PCR-confirmed SARS-CoV-2 infection from the entire region were treated on an
inpatient basis at hospital B (566 beds).
Radiology departments at hospitals A and B
The radiology department at hospital A is comprised of 16 physicians, 29 radiology
technicians at 2 locations and 5 staff members in the administrative office ([Table 2]). One CT unit is installed at the main site of hospital A (649 beds) and one at
the second site (145 beds). The numbers were similar at control hospital B with 10 physicians
and 28 radiology technicians. Hospital B is also equipped with similar equipment with
the exception of having 2 CT scanners at one location.
Table 2
Aggregation of key data characterizing the two evaluated radiological departments
at hospital A (high prevalence) and hospital B (low prevalence) regarding radiological
equipment and staff during the study period from March to July 2020.
|
modalities
|
hospital A
|
hospital B
|
|
CT
|
2
(at two locations)
|
2
|
|
MRI
|
2
|
2
|
|
angiography
|
2
|
1
|
|
conventional stationary and mobile X-ray machines
|
7
|
7
|
|
personnel
|
|
|
|
physicians
|
16
|
10
|
|
those tested for antibodies
|
15
|
10
|
|
radiological technicians
|
29
|
28
|
|
those tested for antibodies
|
25
|
28
|
|
administrative staff
|
5
|
4
|
|
those tested for antibodies
|
5
|
4
|
Hygiene concepts at both locations
At the start of the pandemic in Germany, there were no clear guidelines and regulations
regarding interaction with infected patients and the protection of employees. Beginning
in March, all employees at hospital A with patient contact were advised to protect
themselves from infection with the SARS-CoV-2 virus by wearing personal protective
equipment (PPE). In radiology, all employees were required to wear mouth and nose
protection beginning on 3/9/2020. In the case of examination of patients with suspected
COVID or confirmed infection (COVID+), the wearing of FFP2 masks (filtering face piece)
was mandatory, provided that such masks were available. In CT and angiography, additional
wearing of goggles or face shields was advised to provide greater protection. The
use of disposable gowns and disposable gloves was mandatory in the case of direct
contact with patients. Due to the rapid increase in cases within one week in mid-March,
it was not possible to assign personnel to various teams or to individual radiology
modalities. This situation was further aggravated by disease and suspected cases among
radiology personnel.
COVID and COVID+ patients were examined using X-ray equipment set up specifically
for them. Since only one CT scanner was available at each of the two sites of hospital
A at the time of the pandemic, an attempt was made to minimize CT examinations among
these patients if clinically feasible. However, this was only possible to a limited
extent due to the high number of patients and the small number of available PCR tests.
Some PCR tests were also negative in spite of clear symptoms of an infection so that
CT had to be used for further workup of the infection. The units had to be wiped with
disinfectant after every examination of these patients. MRI examinations of COVID
patients were always performed on the same scanner. The second unit was reserved for
non-infected patients.
Similar hygiene measures were implemented at hospital B. Since two CT units were in
operation there, one scanner was dedicated to the examination of COVID+ patients.
In addition, an attempt was made in accordance with organizational recommendations
for radiology [8]
[9] to prevent mixing of radiology personnel between different devices and modalities.
Analysis of radiological examinations of COVID-positive patients
For our study, we examined all patients with a COVID-19 infection confirmed by PCR
test and treated between 3/1/2020 and 6/30/2020 at hospitals A and B. All patients
with PCR test during their inpatient stay were identified at both hospitals and the
number of radiological examinations of these patients was recorded. An anonymized
and cumulative list was compiled to show how many conventional radiological examinations,
CT examinations, MRI examinations, and angiography examinations were performed. Since
sonographic examinations of COVID+ patients were performed by the treating physician
in the wards at hospital A in the high-risk region in order to minimize patient transport
to the radiology department, this data could not be evaluated retrospectively.
Evaluation of the antibodies of medical personnel
In the last two weeks of July 2020, blood samples were collected from the employees
of the radiology departments at both hospitals in accordance with the guidelines of
good clinical practice (GCP) according to the Declaration of Helsinki. Evaluation
was performed as part of testing of the entire hospital staff for SARS-CoV-2 antibodies.
Participation was voluntary. The data was pseudonymized. The ethics committee approved
the scientific evaluation of the results and the examined employees provided written
informed consent (hospital A: number of the Bavarian State Chamber of Physicians 20 043;
hospital B: E-01–20 200 409).
Blood was collected from the participants in a standardized manner. Hospital A used
the immunoassay Elecsys® Anti-SARS-CoV-2 test (Roche Diagnostics, Germany) to test for combined IgM and IgG
antibodies, while hospital B used Euroimmun Anti-SARS-CoV-2-ELISA (Euroimmun Medizinische
Labordiagnostika, Lübeck, Germany) to test for the presence of IgG and IgA antibodies.
Due to the limited specificity of IgA antibodies in corona-SARS-CoV2 infection [10]
[11], the results of the combined IgM/IgG/IgA test (hospital A) and the separate IgG
and IgA tests (hospital B) were evaluated to ensure the comparability of the results
of both hospitals.
In addition, a questionnaire was provided to each employee to evaluate whether and
to what extent each participant had experienced typical clinical symptoms of a COVID-19
infection.
Results
COVID-19-positive patients
At hospital A, a total of 1450 patients with COVID or suspicion of COVID were treated
on an inpatient basis between March and June 2020. 594 had positive PCR result. The
first patient was admitted on an inpatient basis on 3/4/2020 ([Table 3]).
Table 3
Contact of COVID-19-positive patients with radiology and evaluation of different examination
modalities in both hospitals (study period from March to July 2020).
|
hospital A
|
hospital B
|
|
beds at the hospital
|
774
|
|
566
|
|
|
day of admission of the first COVID-19-positive patient
|
|
3/4/2020
|
|
3/30/2020
|
|
COVID-19-positive patient contact with radiology
|
|
contact/images per COVID-19-positive patient
|
|
contact/images per COVID-19-positive patient
|
|
total number of times contact occurred
|
2723
|
4.58
|
64
|
1.28
|
|
X-ray
|
1885
|
3.17
|
52
|
1.04
|
|
CT
|
683
|
1.15
|
10
|
0.2
|
|
MRI
|
149
|
0.25
|
0
|
0
|
|
angio (DSA)
|
6
|
0.01
|
0
|
0
|
|
ultrasound
|
N/A
|
N/A
|
2
|
0.04
|
|
|
|
|
|
|
radiologists
|
15
|
|
10
|
|
|
physicians who tested positive for antibodies (IgG)
|
2
|
13.3 %
|
0
|
0.0 %
|
|
|
|
|
|
|
radiological technicians
|
25[*]
|
|
30
|
|
|
radiological technicians who tested positive for antibodies (IgG)
|
6
|
24.0 %
|
0
|
0.0 %
|
|
|
|
|
|
|
radiological administrative/clerical staff
|
5
|
|
4
|
|
|
administrative staff who tested positive for antibodies (IgG)
|
0
|
0.0 %
|
0
|
0.0 %
|
* (25 of 29 tested on a voluntary basis at hospital A)
At hospital B, a total of 50 PCR-positive COVID-19 patients were treated on an inpatient
basis in the study period. The first positive patient was admitted on an inpatient
basis on 3/30/2020.
Radiological examinations of PCR-positive patients
A total of 2723 examinations of 594 PCR-positive COVID-19 patients were performed
by radiology personnel at hospital A in the study period ([Table 3]). On average at hospital A, 3.17 conventional X-ray examinations (n = 1885) were
performed per patient, 1.15 CT examinations (n = 683), 0.25 MRI examinations (n = 149),
and 0.01 angiography examinations (DSA) (n = 6). Ultrasound examinations of COVID-19
or COVID+ patients were performed primarily by the treating department in the ward
to minimize the transport of patients within the hospital. Therefore, no statistical
evaluation can be performed here.
At hospital B, 50 PCR-positive COVID-19 patients were admitted on an inpatient basis
in the study period and only 1.28 radiological examinations were performed per patient.
Conventional chest X-ray was performed most frequently (n = 64) with an average of
1.04 examinations per patient followed by CT examinations (n = 10) with an average
of 0.2 examinations per patient.
Antibody prevalence among employees
The antibody prevalence of the entire hospital staff (n = 277/1838) at hospital A
including hospital administration was 15.1 % in July 2020 (95 % confidence interval
(CI): 13.4–16.7 %), with 20.0 % being among the nursing staff and 12.0 % among the
physicians. 60 % of the seropositive employees stated that they had lost their sense
of taste and/or smell in the last 3 months. 36.6 % experienced trouble breathing,
34.4 % had fever, and 28.6 % reported a general feeling of weakness. Only approximately
20 % experienced a cough and a sore throat.
The subgroup analysis for radiology showed that a total of 84.9 % (45/53) of the radiology
personnel at hospital A had been tested. 17.8 % were seropositive for SARS-CoV-2 antibodies.
Radiology technicians were most affected (24 %; 6/25). 5 of those infected had clear
symptoms including fever and cough and 4 also lost their sense of smell. Due to their
symptoms, they quarantined until they were symptom-free and could present two negative
PCR tests. One employee did not notice any symptoms and also did not receive a PCR
test. 13.3 % (2/15) of the radiologists at hospital A tested positive for antibodies.
Both of them had typical COVID symptoms including high fever, loss of the sense of
smell, loss of appetite, and abdominal symptoms.
By July 1, 2020 at hospital B, the antibody prevalence for anti-SARS-CoV2 IgG for
the entire hospital was only 2.1 % (CI: 1.2 % to 3.8 %) (13/585 employees). Employees
who tested positive most frequently experienced headache (50 %) followed by fatigue
(42 %), dyspnea (33 %), and an unproductive cough (25 %). Only one employee who tested
positive experienced loss of taste or smell (8 %).
For the subgroup analysis of radiology employees (n = 42), none tested positive for
anti-SARS-CoV-2 IgG (0 %).
Discussion
Due to the greater exposure to infected persons, HCWs must be classified as a high-risk
group for infection with SARS-CoV-2 [12]. Primarily activities performed close to the patient, such as intensive care and
physiotherapy, and also frequent and close patient contact as in radiology potentially
result in high infection rates of hospital personnel. A long-lasting coronavirus wave
can result in a loss of regional control of the medical management of the pandemic
[13]. Infection rates from Italy and Spain showed a cumulative prevalence for SARS-CoV-2
among HCWs of 9–38 % [14]
[15].
Occupational risks
Greater prevalence of COVID-19 in a region increases the individual risk of infection
primarily due to transmission in private and public life [16]
[17].
In addition to their personal risk, HCWs have a significantly higher occupational
risk of infection that increases with greater contact with infected persons [13]
[18].
In radiology, contact of individual employees with COVID+ patients can be tracked
relatively precisely by evaluating the examinations that were performed. In comparison
to other areas in the hospital and to other affected regions, this allows good stratification
of the risk posed to radiology personnel. Direct patient contact and close physical
proximity to infected persons, e. g. in the case of conventional chest X-rays at the
patient bedside, CT examinations, rectal or oral contrast enhancement, and interventions,
are recognized as risk factors for occupational infection with SARS-CoV-2 [19]. In the study at hospital A, 988 employees at a neighboring non-medical business
were examined as the control group to determine the infection risk for regional workers
in order to be able to better assess the infection risk of people in the region in
private life. The seroprevalence for SARS-CoV-2 antibodies at the company was highly
significantly lower (3.7 %; p > 0.0001) than among hospital personnel (15.1 %) [20]. Based on this data, it is possible to approximate the private risk compared to
the occupational infection risk in the particular region. Of course, a clear allocation
of the particular infection site is not possible.
The fact that radiology technicians are more affected than physicians is a further
indication that direct contact to patients and a greater number of times of contact
additionally increase the risk.
Primarily during the first wave of the COVID-19 pandemic, the lack of knowledge about
the disease, the large number of patients in many locations, and the lack of personal
protective equipment in some cases resulted in a significantly higher risk for radiology
departments at hospitals with a high COVID-19 prevalence. The use of chest X-rays
and primarily CT examinations for diagnosis and for follow-up of the disease course
results in repeated contact between radiology employees and patients especially during
the potentially infectious phase. Infected radiology technicians at hospital A primarily
worked in computed tomography prior to becoming infected. However, given the rapid
increase in the number of patients at the end of March 2020, it was no longer possible
to assign employees to individual modalities. As a result of the high rate of asymptomatic
people and a relatively long incubation period, it can no longer be retrospectively
clarified where the personnel became infected.
Among the HCWs in this study, 10.1 % of all seropositive employees did not experience
any typical COVID-19 symptoms. Asymptomatic employees can be potential spreaders within
their own department so that transmission from HCW to HCW is also relevant here. Therefore,
affected hospitals can be a site of transmission or further transmission of the virus
both for patients and for the hospital's own personnel even if all hygiene regulations
are observed [12].
Recognition of COVID-19 as an occupational disease
Given the risk of occupationally acquired infection with SARS-CoV-2 with potential
long-term effects, COVID-19 infection can be recognized as an occupational disease
for employees in the health care industry [21] and guidelines for testing HCWs have been developed [22]
[23]. By September 2020, almost 19 000 cases of occupational disease in connection with
COVID-19 had been reported to the statutory accident insurance companies in Germany.
Approximately 43 % of these cases had already been recognized at this time. In the
case of occupational contact with SARS-CoV-2, corresponding symptoms of the disease,
and a positive PCR test result, employees should consider reporting the justified
suspicion of an occupational disease to the responsible statutory accident insurance
company [24]. Since the risk for employees in radiology departments seems to be similarly high
as for those working in COVID wards or in the ICU, protection of these employees must
be given highest priority. Persons infected in the course of performing their occupational
duties should be notified of the possibility of reporting their infection to their
employer or medical officer since the long-term effects of a SARS-CoV-2 infection
are still unclear.
Limitations of the study
Data was collected over a period of 4 weeks. Due to the relatively rapidly spread
of the infection, an exact date for the point prevalence of seropositivity cannot
be specified. Instead, the period from the end of June to the end of July 2020 is
used for analysis. However, the study still provides sufficiently accurate data regarding
the first surge of the pandemic in Germany based on the examined time period from
March to July 2020. The method does not allow differentiation of private sources of
infection from cases of nosocomial transmission. Unfortunately, this problem affects
almost all studies regarding this topic. The highly significant increase in the infection
rate of HCWs at hospital A compared to individuals in the same region working in the
non-medical sector makes it possible to at least classify the risk posed by working
at a hospital. However, exact determination of the particular infection site of affected
individuals remains speculative. Unfortunately, it is not possible to retrospectively
differentiate the risks for radiology staff based on area of operation due to the
complexity of processes and the numerous possibilities for infection during the daily
routine. Finally, the use of two different antibody tests at the two evaluated hospitals
must be mentioned as a study limitation. However, since the information provided by
the manufacturer regarding sensitivity and specificity differs only slightly, this
should not have a relevant effect on our analysis.
Conclusion
The risk of a SARS-CoV-2 infection is as high for radiology staff as for nurses and
physicians in dedicated COVID-19 wards or in the ICU. The risk increases with the
regional prevalence of disease and the number of times of contact with persons infected
with COVID-19. It is extremely important to observe hygiene regulations and to ensure
personal protection of employees during the pandemic, particularly in high-risk regions.
The long-term effects of occupationally acquired SARS-CoV-2 have not yet been determined.
Those affected should be advised to report an occupational infection as a potential
occupational disease. Workflows and hygiene concepts adapted to the situation at each
particular hospital are needed for further waves of the infection.
-
The risk of an occupational SARS-CoV-2 infection is similarly high for radiology personnel
in high-risk regions as for nurses and physicians in COVID wards.
-
Hygiene concepts and resources in radiology must be optimized for further waves of
infection.
-
For SARS-CoV-2 seropositive employees in the health care industry, recognition of
the infection as an occupational disease can be considered.
