A health worker holds a box of the AstraZeneneca vaccine at the Bamrasnaradura Institute for Infectious Diseases in Nonthaburi Province on the outskirts of Bangkok.
Chaiwat subprasome | SOPA pictures | LightRocket via Getty Images
LONDON – The coronavirus vaccine developed by AstraZeneca and Oxford University has been exposed in a number of countries in Europe and Asia after reports of blood clots in some vaccinated people. However, many other nations have defended their use of the shot and announced that they will continue their respective vaccination campaigns.
Thailand became the first Asian country to stop using the sting on Friday due to safety concerns, shortly after Denmark announced a two-week hiatus from its nationwide rollout after reports of blood clots and a death.
In a setback to the battered vaccination campaign in Europe, eight other countries have also stopped using the Oxford AstraZeneca shot: Norway, Iceland, Bulgaria, Luxembourg, Estonia, Lithuania and Latvia.
Austria and Italy have since announced that they will no longer use certain batches of the vaccine as a precaution.
The European Medicines Agency, the European Medicines Agency, stressed Thursday that there was no evidence that the shot was causing blood clots, adding that the vaccine's benefits "continue to outweigh the risks".
The EMA acknowledged that some member states had stopped using the Oxford-AstraZeneca shot, but said vaccinations may continue to be given while a clot investigation is ongoing.
By Wednesday, around 5 million people in Europe had received the Oxford-AstraZeneca vaccine. Of this number, 30 cases of so-called "thromboembolic events" were reported. These cases relate to blood clots that form in the blood vessels and block blood flow.
AstraZeneca said the vaccine has been extensively studied in Phase 3 trials and peer-reviewed data confirms the shot is "generally well tolerated."
Why do countries pause vaccination campaigns?
The Thai Ministry of Health announced on Friday that it would temporarily postpone the use of the Oxford-AstraZeneca vaccine. The shot is reportedly labeled a "good vaccine" but is said to be suspended for safety investigation.
Kiattiphum Wongjit, permanent secretary of the health ministry, said the Southeast Asian country may suspend its vaccination campaign as it has largely controlled a second wave of Covid cases through quarantines and border controls, according to Reuters.
A press conference will be held on March 12, 2021 in Bangkok, Thailand to temporarily suspend the introduction of vaccination against AstraZeneca Covid-19 in Thailand.
Xinhua | Rachen Sageamsak via Getty Images
The country of nearly 70 million people has so far recorded around 26,600 cases and 85 deaths, according to Johns Hopkins University.
The decision of Thailand to suspend the planned launch of the Oxford-AstraZeneca vaccine, which was due to start on Friday, was made following the decision of the Danish health authority.
"It is important to emphasize that we have not decided against the AstraZeneca vaccine, but are putting it on hold," said Soren Brostrom, director of the National Health Agency in Denmark, on Thursday.
"There is good evidence that the vaccine is both safe and effective. However, we and the Danish Medicines Agency need to respond to reports of possible serious side effects from both Denmark and other European countries."
Many high-income countries have chosen to continue rolling out the Oxford-AstraZeneca vaccine for safety reasons.
The UK, France, Australia, Canada and Mexico are among the nations that have tried to reassure citizens about the benefits of the vaccine and have announced that they will continue their respective vaccination campaigns.
What do the experts say?
The EMA's safety committee is investigating the problem but has determined that there is currently no evidence that the vaccination caused blood clots. It should be noted that these are not listed as side effects of this vaccine.
The European Medicines Agency also noted that the data available so far showed that the number of blood clots in vaccinated people is no higher than in the general population.
"Reports of blood clots received to date are no greater than the numbers that would have occurred naturally in the vaccinated population," said Dr. Phil Bryan, Vaccine Safety Director for the UK Medicines and Health Products Regulatory Agency.
"Public safety will always come first. We will continue to examine this issue carefully, but the evidence available does not confirm the vaccine is the cause. People should still get their COVID-19 vaccine when prompted become." Said Bryan.
Peter Brownsea, a Southampton resident, receives the Oxford / AstraZeneca Covid-19 vaccine from a member of the Hampshire Fire and Rescue Service at a temporary vaccination center at the Basingstoke Fire Station in Hampshire, southern England, while crews continue to answer 999 emergency calls.
Andrew Matthews | AFP | Getty Images
Stephen Evans, Professor of Pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, said: "The problem with spontaneous reports of suspected vaccine side effects is the tremendous difficulty in distinguishing a causal effect from a coincidence."
"This is especially true when we know that Covid-19 disease is very closely related to blood clotting and that there have been hundreds, if not many thousands, of deaths caused by blood clotting as a result of Covid-19 disease, in absolute terms to be sure the clots weren't caused by any other cause, including Covid-19, "added Evans.
How does the vaccine work?
The Oxford AstraZeneca vaccine is designed to prevent coronavirus in people aged 18 and over. It's made up of an adenovirus that has been modified to contain the gene to make a protein from SARS-CoV-2, the virus that causes Covid-19.
The most common side effects of the shot, which does not contain the virus and cannot cause Covid, are typically mild or moderate and improve within a few days after vaccination.
In late clinical studies, the AstraZeneca Oxford shot was found to have an average of 70% effectiveness in protecting against the virus.
A recent study by Oxford researchers found that the Covid vaccine was 76% effective at preventing symptomatic infection for three months after a single dose and that the effectiveness rate actually increased with a longer interval between the first and second dose.
– CNBC's Holly Ellyatt contributed to this report.