Use of ward closure to control outbreaks among hospitalized patients in acute care settings: a systematic review

We sought to identify studies that describe the use of ward closure as an intervention
in outbreak control and determine its importance. Our systematic review expands on
existing work by providing an extensive review of the epidemiological literature on
the use of ward closure as an intervention to control outbreaks of pathogenic microbes
among inpatients hospitalized in acute care settings. We identified 97 studies that
described the use of ward closure as part of a bundled approach to their strategy.
None of the studies used ward closure in a setting where it was able to be isolated
as a singular control measure, limiting our assessment of the direct efficacy of ward
closure on outbreak containment, which was one of our primary objectives.

It was not possible to draw any firm conclusions about the impact or effect of ward
closure from the studies for a number of reasons. Firstly, the use of “ward closure”
varied considerably within the papers included in the review. Our review was unable
to identify whether partial or complete closure was instituted in the vast majority
of the studies, as precise definitions were not used to describe the type or nature
of ward closure. The results suggest that there is not a universal definition of “ward
closure”; rather, ward closure refers to restrictions on patient movement into and
out of a unit/ward or a facility and could encompass a number of qualities and multiple
phases and/or degrees of application. Secondly, with the exception of the prevention
and control policy and intervention studies, all of the studies of the included papers
were reports or descriptions of outbreak investigations. As investigators could not
manipulate exposures (i.e., the outbreak), all outbreak studies were observational
in nature and the results were thus susceptible to a number of potential confounders.
The vast majority of the included articles did not record these potential confounders
or were not adjusted accordingly in any type of additional analysis. The studies were
vulnerable to multiple biases, including confounding factor bias, publication bias,
and recall bias, and none of them reported taking measures to prevent them or address
their source. As Cooper and colleagues 115] noted, these studies generally did not meet standards of planned research as most,
if not all, outbreak reports were written retrospectively. Thus, the majority of the
included studies were considered to be of poor quality as the nature of outbreak investigation
reports rendered the use of high-quality study designs such as randomized controlled
trials unfeasible. Thirdly, all of the studies used combinations of measures in an
attempt to reduce or terminate transmission. As a result, the relative contribution
of each measure, and especially ward closure, could not be determined. The lack of
attribution could be due to the reporting style, as many authors listed all the measures
used without providing information on whether they were instituted consecutively or
concurrently. Overall, ward closure was generally used at a late stage in conjunction
with other measures, primarily hygienic and disinfection measures. Finally, considerable
variability across the studies limits the generalizability and comparability of the
outcomes of the studies. Thus, we considered the conclusions to be very weak when
authors stated that the containment of an outbreak could be attributed to any one
of the measures used as potential alternative factors accounting for the main findings
could not be dismissed.

Our review highlights potential areas for further research on the role of ward closure
as an intervention measure for managing and terminating outbreaks. Improving the quality
of reporting can be a first step to addressing the difficulties in assessing the applicability
and generalizability of these studies 116]. Given the complexities of outbreak investigations and the nature of the studies,
clear and detailed reporting enables greater understanding of the context of the outbreak,
the outbreak itself, and the control measures used, which may or may not include ward
closure. Reports of outbreaks that use ward closure should include a clear definition
or description of ward closure, timing of ward closure, and at which point it was
used in the investigation. Given the nature of outbreak investigations, an experimental
design would not be feasible. However, since the role if any of ward closure in containing
outbreaks is unknown, quasi-experimental design is ethically unacceptable. Future
research can improve the rigor and internal validity by using study designs of higher
quality such as prospective cohort studies and cluster randomized trials. For example,
a cluster randomized design study of ward closure, or no ward closure plus a defined
bundle of other interventions for specified outbreak organisms, could be conducted.

Further, formal assessment of the frequency and outcomes of unit closure versus no
unit closure during an outbreak could be undertaken. This should include gathering
information on the type of outbreak where a unit is closed, duration of the outbreak,
whether or not the unit is closed, and the impact on patient flow, examining both
admission and discharge. While there are some inconsistencies in the quality and format
of reporting, there are some metrics that are consistently reported, including number
of beds, length of closure, and bed-days lost. This information could inform an economic
study using modeling to predict the cost of implementing ward closure. Finally, there
are potential ethical and legal considerations in deciding whether to implement closure
of care settings during outbreaks that are not addressed in the literature reviewed
nor within this review. On the one hand, failure to restrict admissions implies that
new and unaffected patients are knowingly admitted to an area known to have ongoing
transmission of a potential pathogen; on the other hand, closure of a clinical area
may reduce access to care.

While this review was undertaken with rigor and in accordance with the requirements
of systematic review methodology, it is important to note its limitations. Firstly,
for the majority of articles, data were extracted by a single reviewer; however, initial
screening was undertaken rigorously by two reviewers, and disagreements were resolved
with a third-party adjudicator. Secondly, the literature available for this review
could report a positive effect of ward closure, as it is possible that there are many
outbreaks that were controlled without using ward closure and were never published.
Similarly, outbreaks where interventions failed to control transmission leading to
endemic transmission are less likely to be published. For example, it is common for
long-term care facilities to use ward (or facility) closure (along with other interventions)
to control gastrointestinal and respiratory outbreaks, and these are seldom published.
While the outbreaks are generally controlled and the ward (or facility) is re-opened,
the key question is whether ward closure is necessary and effective. Lastly, the review
is based on the last electronic search which was completed in July 2014, and as such
the review may not be entirely up to date.

It can be concluded that ward closure for containment of outbreaks remains an intervention
that is not evidence based in the traditional sense; however, this review demonstrates
that ward closure is frequently used and was always used as part of a bundled approach,
whether as part of a sequence of, or in parallel with, other interventions, and in
this sense, is similar to other public health responses. However, it was interesting
to observe that in the majority of the studies in this review, ward closure was applied
in the late stages of the overall outbreak response rather than as a first measure.
In addition, in 16 studies, despite the use of ward closure, additional cases continued
to be reported, suggesting that ward closure was not an effective intervention in
these settings. Other than general wards, which were not described well, burn units
(?=?3), geriatric wards (?=?3), and neonatal intensive care units (?=?2) were reported more than once (Tables 1, 3, 4, 5, and 6). The most frequently recorded mode of transmission was contact with viral gastrointestinal-associated
viruses (four norovirus and one small round structured virus) and bacterial (S. panama, C. difficile, E. faecium, and E. coli), making up 56 % of the pathogenic species. These pathogens are known for their persistence
within environmental niches and relative resistance to commonly used disinfectants.

There are also potential ethical considerations in the closure of wards during outbreaks
that are not addressed within the context of the reviewed studies and would need to
be taken into consideration by infection control personnel and hospital administrators.
Admitting new and unaffected individuals to a hospital ward that is known to have
ongoing transmission of a potential pathogen, particularly if associated with a high
case fatality rate, warrants careful deliberation. The risk of new transmissions needs
to be juxtaposed against the failure to contain the outbreak despite closure, the
disruption of care delivery, and lack of access to care for other patients and overloading
other care units, particularly emergency departments, where the risks of overcrowding
and delayed care present other challenges.

With no published controlled studies associated with a benefit from ward closure,
infection control practitioners and hospital administrators will need to continue
to balance the competing risks, taking into consideration the nature of the outbreak,
the type of pathogen and its virulence, mode of transmission, and the setting in which
it occurs and take reasonable steps to protect patients, and since ward closure has
been used in the past, it will likely continue to be used as an intervention strategy
until better quality evidence is available.