Health care workers (HCWs) are at increased risk for infection in outbreaks of Ebola
virus disease (Ebola) (1). To characterize Ebola in HCWs in Sierra Leone and guide
prevention efforts, surveillance data from the national Viral Hemorrhagic Fever database
were analyzed. In addition, site visits and interviews with HCWs and health facility
administrators were conducted. As of October 31, 2014, a total of 199 (5.2%) of the
total of 3,854 laboratory-confirmed Ebola cases reported from Sierra Leone were in
HCWs, representing a much higher estimated cumulative incidence of confirmed Ebola
in HCWs than in non-HCWs, based on national data on the number of HCW. The peak number
of confirmed Ebola cases in HCWs was reported in August (65 cases), and the highest
number and percentage of confirmed Ebola cases in HCWs was in Kenema District (65
cases, 12.9% of cases in Kenema), mostly from Kenema General Hospital. Confirmed Ebola
cases in HCWs continued to be reported through October and were from 12 of 14 districts
in Sierra Leone. A broad range of challenges were reported in implementing infection
prevention and control measures. In response, the Ministry of Health and Sanitation
and partners are developing standard operating procedures for multiple aspects of
infection prevention, including patient isolation and safe burials; recruiting and
training staff in infection prevention and control; procuring needed commodities and
equipment, including personal protective equipment and vehicles for safe transport
of Ebola patients and corpses; renovating and constructing Ebola care facilities designed
to reduce risk for nosocomial transmission; monitoring and evaluating infection prevention
and control practices; and investigating new cases of Ebola in HCWs as sentinel public
health events to identify and address ongoing prevention failures.
For this report of Ebola in HCWs in Sierra Leone, data were analyzed on laboratory-confirmed
cases in the national Viral Hemorrhagic Fever database, which was created to capture
and analyze data from the 2014 Ebola outbreak. Surveillance officers used a standardized
case investigation form to collect information from patients with suspected or probable
Ebola (2) and their family members. Information collected included age, sex, address,
occupation, date of onset of symptoms, and potential exposures to other Ebola patients.
“Health care worker” was one of the choices listed under a patient’s occupation and
included clinicians such as doctors and nurses, as well as members of other cadres,
including ambulance drivers, hospital cleaners, and burial team members. Vital status
and laboratory information were entered into the patient’s case record as results
were reported to the surveillance team in each health district. District data were
merged at the national level. Whole blood from live patients and oral swab specimens
from corpses were sent to one of several laboratories in Sierra Leone. Reverse transcription–polymerase
chain reaction assays were used to confirm Ebolavirus infection. Select characteristics
of HCW and non-HCW cases were compared using chi-square tests. P-values <0.05 were
considered significant. To inform infection prevention and control efforts and surveillance
of Ebola in HCWs, unstructured interviews concerning HCW infections were conducted
with HCWs and health facility administrators in the course of site visits to health
care facilities in eight districts during August–October 2014.
During May 23 through October 31, 2014, there were 3,854 laboratory-confirmed cases
of Ebola reported in Sierra Leone in the Viral Hemorrhagic Fever database, including
199 cases in HCWs (5.2%). Seven additional cases in HCWs and 949 cases in non-HCWs
had dates of symptom onset that were missing or outside of May 23 (date of the first
documented case) to October 31 and were excluded from analysis. According to the National
Health Strategic Plan 2010–2015, published in 2009 (3), Sierra Leone had a total health
workforce of 2,402 persons. Using this denominator, the cumulative confirmed Ebola
incidence in HCWs was 8,285 per 100,000. This can be compared with the 2,806 confirmed
Ebola cases in non-HCWs in a national population of 3.49 million persons aged ≥15
years, with a cumulative incidence in adult non-HCWs of 80.4 per 100,000 population.
Therefore, the confirmed Ebola incidence was 103-fold higher in HCWs than that in
the general population in Sierra Leone.
Among confirmed cases in HCWs, 54.8% were in males, compared with 48.2% in non-HCWs
(p=0.09). Of 183 (92%) confirmed Ebola cases in HCWs with recorded age, two (1.1%)
were reportedly in persons aged <15 years, 82.0% were in persons aged 15–49 years,
and 16.9% were in persons aged ≥50 years. There were no confirmed Ebola cases in HCWs
reported in May. The number peaked at 65 cases in August and declined to 36 in September
and 42 in October (Figure 1). The highest percentage of confirmed Ebola patients that
were HCWs was in August (9.2%); this declined to 3.5% in October (Figure 1). The number
of confirmed Ebola cases in HCW per district ranged from zero in two districts to
65 cases in Kenema District (Figure 2), which also had the highest percentage of all
confirmed Ebola patients that were HCWs (12.9%). District of residence was missing
in seven cases in HCWs (3.5%).
The surveillance form included questions on potential sources of infection, specifically
attendance at a funeral or contact with a person with known or suspected Ebola, with
an ill person, or with a corpse in the month before onset of symptoms. Among 159 (80%)
confirmed HCW Ebola cases with data on funeral attendance, 13.8% had attended a funeral,
compared with 32.3% in non-HCW (p <0.001). Data on contact with a known or suspected
Ebola patient or ill person or a corpse was available for 143 (72%) confirmed HCW
Ebola cases; 18.2% were in persons who had contact with a person with known or suspected
Ebola or an ill person, compared with 12.3% in non-HCWs (p = 0.05); 30.1% had contact
with a corpse, compared with 34.3% in non-HCWs (p=0.3).
Among confirmed HCW Ebola patients, 12.1% were dead at the time of surveillance recording,
compared with 15.0% among non-HCW patients (p=0.3); other data on vital status, including
numbers with missing data at time of surveillance recording and final outcome, are
not consistently available in the Viral Hemorrhagic Fever data.
Site visits and unstructured interviews with HCWs and health facility administrators
revealed a broad range of circumstances potentially leading to Ebola in HCWs. These
included a lack of standard operating procedures and clearly assigned responsibilities
for infection prevention and control; overall staff shortages and lack of infection
prevention specialists; limited availability of safe transport vehicles for patients
and corpses; incorrect triage or recognition of potential Ebola in patients and corpses,
including no reassessment of admitted patients to identify new symptoms of Ebola (especially
children aged <5 years); delayed laboratory diagnosis of Ebola cases because of long
turn-around time for specimen transport and reporting of results; inadequate control
of Ebola patient or HCW movement within health facilities; and lack of delineation
between high-risk and low-risk Ebola zones. Other findings included limited availability
of appropriate personal protective equipment and hand washing facilities, including
lack of water and sufficient chlorine supplies; no or inadequate training about and
monitoring of personal protective equipment use and hand washing; lack of equipment
and materials and no or inadequate training about and monitoring of decontamination
of transport vehicles and care facility spaces; limited capacity and no or inadequate
training about safe management of contaminated waste; and limited capacity and no
or inadequate training about safe management and burial of corpses.
Discussion
Analysis of the national Viral Hemorrhagic Fever database found 199 cases of Ebola
in the Sierra Leone health workforce. Using the number of HCWs reported in 2009 (3)
as a denominator for HCWs and comparing with infection rates in the general population
aged ≥15 years, the estimated confirmed Ebola incidence rate was approximately 100-fold
higher in HCWs than in non-HCW adults in Sierra Leone.
The number and proportion of all confirmed Ebola patients that were HCWs peaked in
August. The subsequent reductions might be attributable to concurrent implementation
of infection prevention and control measures, including training and availability
of personal protective equipment, and could reflect a closure of many health facilities
and reduction in availability of health care services and HCW exposure as the outbreak
progressed. However, many Ebola cases in HCWs continued to be reported in October.
The highest number of confirmed Ebola cases and the proportion of all confirmed Ebola
case that were HCWs occurred in Kenema District. There were 43 Ebola cases in HCWs
in Kenema District in July and August, mostly among Kenema General Hospital staff.
Inquiries about breaches of infection prevention and control at Kenema General Hospital
indicated, among other problems, challenges with overall site management and administrative
controls, such as correct and consistent triage and isolation of Ebola patients. Although
some districts, such as Kenema, were more heavily affected, confirmed Ebola cases
in HCWs have been reported in 12 of 14 districts in Sierra Leone, including all districts
that have reported more than 35 confirmed Ebola cases. Also, although most cases in
HCWs occurred in facilities operated by the Ministry of Health and Sanitation, including
both general care facilities and those designated for Ebola care, there were a small
number of confirmed Ebola cases in HCWs at Ebola care facilities established and managed
by international implementing partners. These findings underscore the widespread challenges
with infection prevention and control in Sierra Leone.
Compared with non-HCW patients, HCW patients were less likely to have attended a funeral
and were more likely to have had contact with a live Ebola patient or ill person in
the 30 days before symptom onset. However, a substantial proportion of both HCW and
non-HCW Ebola patients reported funeral attendance or contact with a corpse, highlighting
the overall importance of transmission from corpses in this outbreak. HCW patients
were not significantly less likely than non-HCW patients to be dead at the time their
cases were recorded by the surveillance system. The finding that 12% of HCW patients
were dead at the time of recording indicates shortcomings in contact tracing, early
case identification, and access to medical care, even in HCWs, who might have been
expected to have better awareness and access to health care.
The findings in this report are subject to at least four limitations. First, public
health surveillance data were incomplete, especially in the context of a health emergency
in a resource-poor setting. It has been estimated that overall case numbers represent
only one third to one half of all cases (4). Second, data on key information such
as occupation was missing or might have been incorrect on many case investigation
forms, and many cases were not included in the analysis because of missing or out-of-range
dates of onset of symptoms. Third, members of some cadres, such as ambulance drivers,
burial team members, and community health workers, might not have been consistently
recorded as HCWs on case investigation forms or in the Ministry of Health and Sanitation
2009 report on the health workforce (3), and the number of health workers might have
changed since 2009. As a result, these findings likely undercount the number of Ebolavirus-infected
HCWs in Sierra Leone. However, Ebola reporting might be more complete for HCWs than
non-HCWs, so the ratio of the Ebola cumulative incidence in HCWs compared with non-HCWs
might be an overestimate. Finally, data on exposures are also likely to be incomplete.
For example, the finding that contact with an Ebola patient or ill person was reported
for only 19% of HCWs with Ebola is likely an underestimate.
A broad range of potential problems with infection prevention and control were reported
at both general care facilities and those designated for Ebola care. The Ministry
of Health and Sanitation, together with Sierra Leonean and international partners,
are implementing a wide range of interventions, including policies, training, procurement,
renovation, construction, and monitoring and evaluation, in accordance with established
recommendations (5). As is the case with prevention of nosocomial transmission of
tuberculosis (6), many observed breaches of infection prevention and control practices
appeared to be attributed to failures of administrative controls, such as incorrect
triage, or infrastructure limitations of renovated facilities, such as lack of barriers
separating Ebola wards, rather than personal protective equipment failures; particular
attention to these issues is recommended in the control of Ebola.
Cases of Ebola in HCWs are currently being investigated as sentinel public health
events. An infection in an HCW might represent transmission from an Ebola patient
in a health care facility, but might also be a signal for transmission to and from
HCWs in the community, and for facility-based transmission from patient to patient
and from HCWs to patients or to other HCWs. New, high-quality, dedicated Ebola treatment
units are being established by international partners in Sierra Leone, but because
the number of these beds does not meet the need in high-transmission areas, other,
less well-resourced facilities, including Ebola care, holding, and isolation centers,
are being established by the Ministry of Health and Sanitation. Given the high risk
of nosocomial transmission of Ebolavirus (5), health authorities must be vigilant
in implementation of strict infection prevention and control measures in all health
care settings and alert to the possibility that less well-controlled settings might
inadvertently act to propagate rather than interrupt transmission. Prevention of Ebola
in HCWs is also critical to sustain the health workforce to address all causes of
morbidity and mortality in Sierra Leone.
What is already known on this topic?
Health care workers (HCWs) are at increased risk for infection in outbreaks of Ebola
virus disease (Ebola). Adherence to good infection prevention and control practices
are required to prevent Ebola in HCWs.
What is added by this report?
As of October 31, 2014, of the total of 3,854 laboratory-confirmed Ebola cases reported
from Sierra Leone, 199 (5.2%) were in HCWs. This was estimated to be a much higher
cumulative incidence of confirmed Ebola in HCWs compared with non-HCWs. A broad range
of breaches of good infection prevention and control practices were reported, and
Ebola cases in HCW continued to be reported in October.
What are the implications for public health practice?
In Ebola outbreaks, comprehensive programs to reduce the risk for Ebola in HCWs in
all health care settings are needed, including development of standard operating procedures
(including safe triage), recruiting and training staff, procuring needed commodities
and equipment, renovating and constructing safe Ebola care facilities, monitoring
and evaluating infection prevention and control practices; and investigating new cases
of Ebola in HCWs as sentinel public health events to identify and address ongoing
prevention failures.