Health & Environment (South China
Morning Post)
How did the AstraZeneca-Oxford Covid-19 vaccine go from ‘game changer’ to
‘under review’?
·
Safety concerns about rare blood clots and controversy over slow deliveries
threaten to derail the roll-out of the vaccine in many countries
·
Medical experts say it is important that all potential risks are reported,
but they worry that the negative attention could shatter public confidence in
Covid-19 inoculations
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Published:
12:30pm, 10 Apr, 2021
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Countries around the world have moved to
address safety concerns around the AstraZeneca-Oxford coronavirus vaccine.
Photo: TNS
Cheap, highly effective and easier to distribute than rival jabs, the
AstraZeneca-Oxford vaccine was hailed as a game-changer in the global fight
against
.
Months after it was first approved for
use in Britain in December, a public relations crisis over extremely rare side effects
threatens to derail vaccination efforts in numerous Asia-Pacific and
lower-income countries. Countries across the European Union and Britain have
already imposed age restrictions on the use of the shot, including offering
alternatives to those under 30.
But with the vaccine already used in
more than 100 countries – and accounting for almost a quarter of supply deals
this year, according to London-based research firm Airfinity Limited –
authorities from Sydney to Manila to Seoul are scrambling to review their
roll-out of the jab.
The European Medicines Agency on
Wednesday said there was a probable link between the vaccine and a tiny number
of unusual blood clots. The EMA’s analysis was based on a review of 86
instances, including 18 fatalities, reported as of March 22 among some 25
million people who received the AstraZeneca shot in Britain and Europe. On
April 4, there had been 222 reported instances of that type of clotting out of
about 34 million people.
The EMA said it had not identified
specific risk factors and the overall benefits outweighed the risk of side
effects from the vaccine, which is 76 per cent effective at preventing
infection based on Phase 3 trials in the US.
It was the latest in a string of
publicity headaches for AstraZeneca, which teamed up with an Oxford University
team led by vaccinologist Sarah Gilbert to produce the viral vector vaccine,
which was developed using a harmless chimpanzee virus as a Trojan Horse to
trick the immune system into action.
The Anglo-Swedish company has
consistently struggled to meet its supply commitments, sparking backlashes from
European and Asia-Pacific governments, and last month slashed by two-thirds its
target of delivering 90 million jabs to the European Union within the first
quarter.
What is the
latest news on the coronavirus vaccine rollout?
In late March, the US National Institute
of Allergy and Infectious Diseases raised concerns the company had provided
“outdated information” about its latest clinical trials, a snafu that
ultimately had no bearing on the vaccine’s safety and only a marginal impact on
its demonstrated efficacy.
Jerome Kim, director general of the
International Vaccine Institute (IVI) in Seoul, South Korea, said the latest
safety concerns created “confusion, worry, and some reactions that are probably
unjustified”.
“It may cause countries to default to
vaccines that are available but are not yet through WHO approval,” Kim said.
“There will be other vaccines but
getting them approved, made and distributed will result in further delays,
further infection and further possibility of mutant virus generation.”
The Covax Facility, a World Health Organization-backed initiative to ensure equitable global vaccine access, is highly reliant on the AstraZeneca shot, which is easier to distribute and four to five times cheaper than rivals from Pfizer/BioNTech and Moderna. The Pfizer shot also requires ultra-cold storage.
Vials of the AstraZeneca Covid-19 vaccine sit in a fridge at a vaccination
centre in Germany. Regulators expressed concerns about potential side effects
from the vaccine. Photo: AP
RISKS
By all accounts, the potential risks of
the AstraZeneca vaccine are statistically minuscule.
The European regulator estimated blood
clots affected about one in 100,000 people who were given the vaccine;
Britain’s Medicines and Healthcare products Regulatory Agency put the risk even
lower, at one in 250,000 vaccinations, based on a review of 79 cases, 19 of
which were fatal.
Based on the British figures collected
after more than 20 million vaccinations, the likelihood of dying from the jab
stands at around one in 1,000,000. By comparison, there is an approximately one
in 500,000 chance of being hit by lightning in a given year, according to the
US Centers for Disease Control and Prevention.
The risk of dying of Covid-19 ranges
from higher than one in 10 for people in their mid-seventies or older, to
practically zero for those below 50.
Hsu Li Yang, an infectious diseases
expert at the National University of Singapore’s Saw Swee Hock School of Public
Health, said it was difficult to apportion blame over the controversy given the
tiny risks involved and the adherence of standard safety protocols.
“I do not think there is any real blame
here,” Hsu said. “The adverse effect in question is very rare – perhaps 4 per
million vaccinated would develop this condition, which is why it was not picked
up in the licensing clinical trials involving tens of thousands of subjects. It
is testimony to the close monitoring of adverse effects post-Covid vaccination
in the UK and EU countries that allowed such a rare side effect to be picked up
so quickly.”
AstraZeneca has said it is studying the
individual cases to understand the “epidemiology and possible mechanisms that
could explain these extremely rare events”. It is also working with regulators
on their request for new labels on its shots.
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GLOBAL
FALLOUT
Nonetheless, authorities have moved
swiftly to address safety concerns about the vaccine.
In Hong Kong, Secretary for Food and
Health Sophia Chan Siu-chee on Friday announced the government had requested
AstraZeneca to postpone the delivery of 7.5 million doses to the city.
“The main reason is because we already
have enough supplies,” Chan said, adding that she was also concerned about
reports of side effects. “We have also begun looking at next-generation
vaccines that can offer better protection against new virus variants.”
The move came after several experts,
including government adviser David Hui Shu-cheong, called on Hong Kong to
replace its AstraZeneca order – which was due to arrive midyear – with the
Johnson & Johnson vaccine, citing the risk of adverse reactions and reduced
efficacy on coronavirus variants. The city’s vaccination drive, which has been
mired by sluggish uptake, has so far relied on the Sinovac and Pfizer vaccines.
On Friday, Australia said it had doubled
its order of the Pfizer vaccine as authorities raced to overhaul their
inoculation plan originally based on the AstraZeneca shot, which called for 50
million doses – enough for the required two shots for its entire 25 million
population – to be made domestically by biotechnology company CSL Ltd. The
Australian manufacturer said it remained committed to fulfilling its order
after producing about 1.3 million doses since March, with plans to ramp up
production to 1 million doses a week.
Canberra has fallen far short of its
goal to administer at least one dose to 4 million people by the end of March,
blaming the delayed delivery of 3.1 million AstraZeneca doses from Europe, and
is now widely expected to miss its October target of administering at least one
dose to the entire population.
New Zealand Prime Minister Jacinda
Ardern said the AstraZeneca vaccine was still going through the approval
process in the country and only the Pfizer vaccine was currently being
administered.
South Korea, which has secured
AstraZeneca doses for about 10 million people, on Thursday lifted restrictions
on administering the vaccine after briefly suspending inoculations for people
under 60. Medical authorities stressed the importance of keeping up the
vaccination drive, which saw President Moon Jae-in last month receiving his
first AstraZeneca shot.
Health authorities, which have also approved
the Johnson & Johnson and Pfizer vaccines and hope to reach herd immunity
by November, plan to make an official decision on the roll-out of the
AstraZeneca vaccine on Sunday.
A nurse inoculates a woman with a dose of the Covishield/AstraZeneca-Oxford
Covid-19 vaccine in Mumbai, India. Photo: AFP
India, which is producing the
AstraZeneca-Oxford vaccine locally under the name Covishield, said it was
re-examining data on adverse reactions, with a report from the health ministry
expected within days.
New Delhi, which aims to vaccinate 250
million people by the end of July, is considered unlikely to restrict the
roll-out of Covishield, which has accounted for about 90 per cent of the over
90 million vaccine doses administered in the country. The Serum Institute of
India is currently producing about 60 million Covishield doses each month,
compared with about 4 million doses of the locally developed Covaxin, India’s
only other approved vaccine, which Prime Minister Narendra Modi received his
second shot of this week.
“It is a non-issue for India given the size of our population and the fact that Covishield is the mainstay of our campaign,” said Dr Arun Shah, a paediatrician in New Delhi.
Thailand, which briefly suspended the
roll-out of the AstraZeneca jab last month due to safety concerns, has so far
given no indication of any changes to its vaccine drive, under which Siam
Bioscience, a firm owned by King Maha Vajiralongkorn, plans to produce 61
million doses of the British-Swedish vaccine.
The Philippines on Thursday suspended
AstraZeneca shots for people below 60, while Indonesia, which has a warning
against using it in people with a low blood platelet count, said it had reached
out to China for more vaccine supplies after delays in AstraZeneca deliveries.
In the rest of the world, more than a dozen countries have at one time
suspended use of the AstraZeneca vaccine, but most have resumed, with some,
including France, the Netherlands and Germany, recommending a minimum age.
Bloomberg reported that the US stockpile of the jab had grown to more than 20
million doses, even as the shot looks increasingly unlikely to factor in
President
’s domestic vaccination campaign.
FUELLING
HESITANCY
Experts are worried that scepticism
about the AstraZeneca vaccine, already running high in some EU and Asia-Pacific
countries, will spread given the controversy.
In Thailand, the death of a 71-year-old
deputy abbot at a Buddhist temple in Bangkok soon after receiving the
AstraZeneca jab has stoked safety concerns. Authorities said the monk
suffered from obesity and high blood pressure, although his autopsy results are
yet to be released.
Phra Jirakit, who shared the
Samphanthawong temple with the deceased monk, said many of his fellow monks
were now reluctant to take the shot.
“I might wait if other vaccines are
available in Thailand before I can decide to get the second AstraZeneca dose,”
he said. “If the deputy abbot’s death can help benefit science then we don’t
want to blame anyone. I want to wait for a firm study to come out first.”
The rare and as yet ‘unexplained’
blood clots were caught by a safety system that is in place to detect these
eventsJerome Kim, International Vaccine Institute
Parminder Verma, a 62-year-old maths
tutor in New Delhi, said she was concerned about her 26-year-old son receiving
the vaccine as he suffers from the rare blood disorder eosinophilia, which can
cause blood clots.
“We don’t even know if the blood clot
happens after the first dose or the second dose,” said Verma, who has received
her first dose of Covishield along with her husband and had until recently been
anxious to ensure her son is also vaccinated. “We know nothing about the age,
sex or health conditions of those affected.”
Sanghamitra Acharya, professor at the
Centre of Social Medicine and Community Health at Jawaharlal Nehru University
in New Delhi, said it would be crucial for authorities to dispel the “mystery
of the vaccine”.
“In simple language, it needs to be explained to the people what the vaccine is and how it will protect from infection of Covid-19,” Acharya said. “Clear message and assurance is the key.”
Syringes are prepared to administer the AstraZeneca Covid-19 shot at a mass
vaccination centre in Madrid. Photo: Reuters
One prominent vaccine expert in
Australia, who wished to remain anonymous due to the sensitivity of the
situation, said he was deeply concerned about the impact the negative attention
could have on the global vaccine roll-out, suggesting Australia’s advisory was
an example of messaging that would likely shatter public confidence in the jab.
“Like the curate’s egg, the AstraZeneca
vaccine will now be seen to be good in parts,” he said, adding that while authorities
could not deny there was any issue, it was important not “make more of it than
it is”.
Dale Fisher, a professor at the Yong Loo
Lin School of Medicine at the University of Singapore, said while the adverse
reactions were “inconvenient” to the roll-out, authorities had to be honest
with the public about the risks.
“A very, very, rare event in thrombotic
thrombocytopenic purpura is more common after the vaccine but still very rare,”
Fisher said.
“Probably it is less likely than having
a serious car accident on the way to the vaccination centre. People are aware
that serious car accidents occur and take the risk as it’s a way of life. This
small risk of this vaccine in the order of 1 in 250,000 is to restore our way
of life and indeed save lives.”
But Fisher admitted communicating the necessity of vaccinations despite the minuscule risk would be difficult as people tended to be “much more prepared to take risk for a treatment, such as surgery, than they are for prevention”.
Kim of the IVI said it would be up to authorities
in different countries to weigh the costs and benefits of the
AstraZeneca-Oxford shot based on factors such as local demographics and the
prevalence of the virus among the population.
But he expressed hope the jab would
continue to see widespread use, alongside existing rivals and other vaccines
that are yet to come online.
“The rare and as yet ‘unexplained’ blood
clots were caught by a safety system that is in place to detect these events,”
Kim said.
“The development of policy statements by
EMA and many governments have been based on evolving data, and you want that. I
hope that we will be able to find a way to use this vaccine safely, that other
existing approved vaccines continue to full rate production, and that the
as-yet-unapproved vaccines are brought forward, reviewed and approved as
appropriate.”
Additional
reporting by Bloomberg and Agence France-Presse
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