So Far Oxford Vaccine Triggers Hope
Trials involving
1,077 people showed the injection led to them making antibodies and T-cells
that can fight coronavirus.
The findings are
hugely promising, but it is still too soon to know if this is enough to offer
protection and larger trials are under way.
The UK has already
ordered 100 million doses of the vaccine.
The vaccine - called
ChAdOx1 nCoV-19 - is being developed at unprecedented speed.
It is made from a
genetically engineered virus that causes the common cold in chimpanzees.
It has been heavily
modified, first so it cannot cause infections in people and also to make it
"look" more like coronavirus.
Scientists did this
by transferring the genetic instructions for the coronavirus's "spike
protein" - the crucial tool it uses to invade our cells - to the vaccine
they were developing.
This means the
vaccine resembles the coronavirus and the immune system can learn how to attack
it.
Much of the focus on
coronavirus so far has been about antibodies, but these are only one part of
our immune defence.
Antibodies are small
proteins made by the immune system that stick onto the surface of viruses.
Neutralising
antibodies can disable the coronavirus.
T-cells, a type of
white blood cell, help coordinate the immune system and are able to spot which
of the body's cells have been infected and destroy them.
Nearly a
ll effective
vaccines induce both an antibody and a T-cell response.
Levels
of T cells peaked 14 days after vaccination and antibody levels peaked after 28
days. The study has not run for long enough to understand how long they may
last, the study in the Lancet showed.
Prof Andrew Pollard,
from the Oxford research group told the BBC: "We're really pleased with
the results published today as we're seeing both neutralizing antibodies and
T-cells.
"They're
extremely promising and we believe the type of response that may be associated
with protection.
"But the key
question everyone wants to know is does the vaccine work, dose it offer
protection... and we're in a waiting game."
The study showed 90%
of people developed neutralising antibodies after one dose. Only ten people
were given two doses and all of them produced neutralising antibodies.
"We don't know
the level needed for protection, but we can maximise responses with a second
dose," Prof Pollard told the BBC.
The vaccine is safe,
but there
are side-effects.
There were no
dangerous side-effects from taking the vaccine, however, 70% of people on the
trial developed either fever or headache.
The researchers say
this could be managed with paracetamol.
Prof Sarah Gilbert,
form the University of Oxford, UK, says: "There is still much work to be
done before we can confirm if our vaccine will help manage the Covid-19
pandemic, but these early results hold promise."
The results so far
are promising, but their main purpose is to ensure the vaccine is safe enough
to give to people.
The study cannot
show whether the vaccine can either prevent people from becoming ill or even
lessen their symptoms of Covid-19.
More than 10,000
people will take part in the next stage of the trials in the UK.
However, the trial
has also been expanded to other countries because levels of coronavirus are low
in the UK, making it hard to know if the vaccine is effective.
There will be a
large trial involving 30,000 people in the US as well 2,000 in South Africa and
5,000 in Brazil.
There
are also calls to perform "challenge trials" in which
vaccinated people are deliberately infected with coronavirus. However, there
are ethical concerns due to a lack of treatments.
It is possible a
coronavirus vaccine will be proven effective before the end of the year,
however, it will not be widely available.
Health and care
workers will be prioritised as will people who are deemed at high risk from
Covid-19 due to their age or medical conditions.
However, wide-spread
vaccination is likely to be, at the earliest, next year even if everything goes
to plan.
Boris Johnson said:
"Obviously I'm hopeful, I've got my fingers crossed, but to say I'm 100%
confident we'll get a vaccine this year, or indeed next year, is, alas, just an
exaggeration.
"We're not
there yet."
The Oxford vaccine
is not the first to reach this stage, with groups in the US and China also
publishing similar results.
The
US company Moderna was first out of the blocks and its
vaccine can produce neutralising antibodies. They are injecting coronavirus RNA
(its genetic code), which then starts making viral proteins in order to trigger
an immune response.
The companies BioNtech and Pfizer have also had
positive results using their RNA vaccine.
A
technique similar to the Oxford one, developed in China, also also
seems promising.
However, all these
approaches are at the absolute boundary of science and have not been proven to
work before.
More traditional
methods of vaccine development are also being investigated. The company Valneva
is taking the whole coronavirus, inactivating it and then inject it.
In total there are
23 coronavirus vaccines in clinical trials around the world and another 140 in
early stage develoment.
The
UK government has struck deals for 190 million doses of
different vaccines.
This includes:
§
100 million doses of the Oxford
vaccine made from a genetically engineered virus
§
30 million doses of the
BioNtech/Pfizer vaccine, which injects part of the coronavirus' genetic code
§
60 million doses of the Valneva
inactivated coronavirus
These have been paid
for even though it is uncertain which, if any, of the vaccines may prove
effective for immunising a nation with 66m people.
Kate Bingham,
chairwoman of the UK Vaccine Taskforce, told the BBC: "What we are doing
is identifying the most promising vaccines across the different categories, or
different types of vaccine, so that we can be sure that we do have a vaccine in
case one of those actually proves to be both safe and effective.
"It's unlikely
to be a single vaccine for everybody.
"We may well
need different vaccines for different groups of people."
FROM .bbc.com/news/uk
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