The general population
Single event
Here we define a ‘single event’ as an event that will not be routinely
repeated with the same group of individuals (e.g. accessing an airport
for travel, visiting a restaurant, or visiting a stadium as a
spectator). This category encompasses a broad range of scenarios and
recommendations will need to be specific for each setting.
Single event current practices
There is no standardized approach to testing within the community, both
NAATs and antigen tests are being used. As an example scenario, many
airlines and airports are developing pre-flight testing requirements,
and currently these have not been regulated by the international
community or even by local governments.81
When considering the appropriate test, if individuals can isolate
between their test and the access event, then centralized NAATs could be
used to deliver high volumes (e.g. people accessing an airport or a
stadium event). In this asymptomatic population, pooling samples could
be useful in order to maximize the testing capacity, although this may
reduce the sensitivity of tests and, as such, is most appropriate for
use with centralized PCR testing as the most sensitive method of
detection.44,47-49,82 However, this would not be
practical for activities such as visiting a shopping center or
restaurant. Highly sensitive antigen or NAAT point-of-care tests could
be performed by non-laboratory trained personnel in these settings;
however, whilst these tests provide quick results (10–15 minutes), they
may not be suitable to conduct in crowded environments. Lateral flow
antigen tests could be a simple and cost-effective way to test large
groups of people; however, studies report high numbers of false-negative
and false-positive results, meaning COVID-19 precautions should still be
employed.28,83,84
Single event key considerations
When considering testing of the general asymptomatic population for
access to single events, the key considerations should include:
- Population issues (e.g. if the population are asymptomatic). What is
the local prevalence of infection? Are people attending from higher
prevalence regions? This is very important as testing the general
population may result in a high number of false-positive
results83
- Sensitivity requirements for this population and the potential impact
of a false-negative result. Is it necessary to detect all infected
individuals, or only anyone highly infectious? Is catching the ‘most
infectious’ cases sufficient? Will other measures, such as mask
wearing and social distancing, be possible in this setting?
- The feasibility of testing at scale. What scale of testing is possible
in that setting? Is reliable testing feasible? If self-swabs are used,
how is the quality checked and will swabbing be supervised? What is
the prevalence of infection?
Repeat access
Repeat access settings comprise workplaces, universities, schools, and
hospitals, where the same group of people repeatedly interact together.
Repeat access current practices
Testing in repeat access settings is already being widely conducted, for
example, many hospitals are regularly testing their healthcare staff
using NAATs.85 In healthcare staff, regular testing is
leading to the identification of many COVID-19 cases, enabling prompt
isolation and therefore limiting outbreaks within
hospitals.86 In healthcare settings, testing staff has
clear benefits for the costs involved with screening: the prevention of
COVID-19 outbreaks among hospital staff, subsequent staff absences, and
nosocomial transmission to potentially vulnerable patients. Pooling
samples can also help to make screening these populations more resource
efficient.44,82
Professional athletes and their support staff around the world have been
subject to regular testing so that sports can continue during the
pandemic. This is often supported by isolation, social distancing,
personal protective equipment for staff, and other measures to prevent
infection.87-89 In these professional settings, the
funding is often available to test regularly to ensure that the sports
continue to operate, and these decisions sit with the sporting leagues
and national governments.
For schools and universities, NAATs may not be needed, as antigen
testing or LAMP may be sufficient to detect the most infectious cases.
In addition, older students may be able to adhere to some social
distancing and mask wearing measures. Overall, transmission has been
noted to be lower in younger pupils compared with older
pupils.90,91 Whilst the cost–benefit of NAATs for
screening in school students would likely prove inappropriate, antigen
testing may be suitable. Pooling NAAT samples could also help to manage
NAAT testing volumes; however, this should be approached cautiously as
methods are not standardized and pooling techniques are not automated,
which does compromise efficiency.44
In these repeat access settings, a single infection could become an
outbreak. Importantly, local prevalence of infection and necessity of
the contact should be carefully considered before allowing any gathering
of individuals.
Repeat access key considerations
Similarly to single access events, the prevalence of infection is an
important consideration when sampling is being carried out, as well as
the frequency of testing. In Germany, healthcare workers are currently
tested on a weekly basis using a NAAT; however, testing frequency will
need to be determined on the basis of each situation, the risk of
infection, and the cost–benefit.