Could lateral flow tests be used to help schools reopen?
Reports of the government’s
plan for mass testing in schools should be taken with a certain scepticism, writes Sky’s technology correspondent Rowland Manthorpe.
Like masks and lockdowns,
lateral flow tests have become a point of contention during the pandemic. A
debate has raged about how and when they should be used.
Lateral flow tests are small,
portable and give fast results, but their speed comes at some cost to accuracy. The short version of the
accuracy debate goes like this: they should be able to detect the most
infectious people, but they will give some infectious people the all-clear, so
it’s important to use them in the right way, or risk dangerous consequences.
In general, scientists agree
that lateral flow tests can be useful for “red light” testing: picking up asymptomatic cases and stopping them from passing on the virus.
The main worry is about “green
light” testing, or testing to enable. If lateral flow tests are only of limited
accuracy, the argument goes, then you can’t let someone do something
potentially risky on the strength of one.
The concern about testing to
enable is not confined to critics or political opponents of the government. The
UK’s medical regulator, the MHRA has approved lateral flow testing for schools
in order to find infectious staff and students, but it has not licensed them
for keeping contacts in schools.
If one student in a classroom
tests positive, then the MHRA says their close contacts shouldn’t be allowed to
stay in school on the basis of a lateral flow test. That would be a “green
light” test, because it would enable something to go ahead which otherwise
would not happen.
Unless the MHRA changes its
mind, it is hard to see how lateral flow tests will enable every school to stay
open no matter what happens with the virus. The hope must be that they will be
able to stop infections at the gate, not allow life to go back to normal
(although their use could be expanded if pilot programmes showed good results).