24 October 2020 | New Scientist | 7RESEARCHERS in the UK
have announced plans to infect
volunteers with the coronavirus,
starting in January. The aim is to
establish the minimum infectious
dose before testing potential
vaccines. The study will be funded
by the UK government, but has
yet to get final ethical approval.
“The top priority is participants’
safety,” says Chris Chiu at Imperial
College London, whose team will
carry out the study. “We have
spent many months thinking
about the evidence and weighing
up the pros and cons.”
The coronavirus doses will
be created by a company called
hVIVO, as the research requires a
pure, quantifiable source of the
virus, rather than an infection
spreading person to person. The
doses will contain the same strain
that is currently circulating andwill not be weakened in any way.
Volunteers will have the virus
delivered to their nose in droplets.
As soon as they show signs of
infection, they will be given
the antiviral drug remdesivir.
A large trial recently found that
remdesivir didn’t reduce the
death rate from covid-19. However,
that trial involved severely ill
people who had already been
hospitalised, says Chiu. He thinks
giving the drug very early on will
stop the infection spreading to
the lungs. The team will also
consider using other drugs, such
as antibodies, as more evidence
for them becomes available.
Volunteers will be free of known
health conditions and aged from18 to 30. Initially they are likely
to be from white ethnic groups
because of evidence that black,
Asian and minority ethnic people
are more likely to get severely ill.
The team aims to have volunteers
from more diverse backgrounds
as soon as it can do so safely.
The study, involving up to
90 participants, will be done
at the Royal Free Hospital in
London. If any volunteers become
seriously ill, the research will be
paused to assess if it is safe to
continue. However, the team’s
expectation is that most volunteers
won’t even develop any symptoms.
Even if no one gets badly sick,
this first phase could still take
several months if the initial dosesA plan to give the coronavirus to volunteers may help us test potential
vaccines, if it gets ethical approval, says Michael Le PageIntentional infections
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newscientist.com/coronavirus-latestprove to be too low, Chiu says.
That’s because the number of beds
at the hospital available for the
trial are limited, and volunteers
will have to remain quarantined
for weeks even if they don’t
become infected.
This means it could be many
more months before the team can
start testing potential vaccines by
trying to infect volunteers whohave been given a vaccine – known
as human challenge trials – by
which time one or more vaccines
might already be available through
conventional testing. “We are likely
to see results of phase III [vaccine]
trials in the next few months,” says
team member Peter Openshaw
at Imperial College London.
However, many different
vaccines will be developed over
the next three or four years, and
Openshaw says that being able
to do human challenge trials will
be a valuable way of comparing
them. “This will be a way to much
more rapidly compare the efficacy
and safety of vaccines,” says
Robert Read at the University
of Southampton, UK.
Challenge trials limited to
younger people won’t reveal if
vaccines protect the oldest and
most vulnerable, but they can
speed up progress by revealing
which potential vaccines have no
chance of working, says Andrew
Catchpole, chief scientist at hVIVO.
“What it can do is fast-track
vaccines for those groups,” he says.
The researchers will set up a
website where people can register
interest in taking part while the
study awaits approval from the
UK’s Medicines and Healthcare
Products Regulatory Agency and
the Health Research Authority.
Volunteers will be compensated
for their time, but Chiu declined
to say how much they will get. ❚Possible covid-
vaccines are already
in conventional trials“ We have spent many
months thinking about
the evidence and weighing
up the pros and cons”Challenge trials