A new report by researchers including the University of Bristol and King's College London has found that the UK public's preference for the AstraZeneca–Oxford vaccine has declined since March.
In March, the AstraZeneca–Oxford COVID-19 vaccine, Vaxzevria – formerly ChAdOx1 – was at the center of several regulatory agency investigations after a small number of recipients were reported to have experienced a rare blood clotting disorder, cerebral venous sinus thrombosis (CVST).
Watch Coronavirus: What Do We Know About Vaccines and Rare Clotting Disorders? to find out more.
The Medicines and Healthcare products Regulatory Agency (MHRA) released new guidance on April 7 that stated "the benefits of vaccination continue to outweigh any risks but the MHRA advises careful consideration be given to people who are at higher risk of specific types of blood clots because of their medical condition".
To assess the potential impact of this event on vaccine confidence, researchers conducted an online survey between April 1 and April 16, recruiting 4,896 individuals from the UK aged 18–75 years. A longitudinal cohort was included, which involved following individuals that had previously been surveyed on vaccine confidence issues in November–December 2020.
The study findings were also compared to an earlier online survey conducted between March 24–26 in 2,210 UK adults of the same age bracket. The work is part of an ongoing project called "COVID-19 and after: trust and perceptions" funded by the UK Economic and Social Research Council COVID-19 Rapid Response Research.
The survey included a variety of questions, such as:
- Are the following statements true or false?" in response to the statement "The AstraZeneca vaccine causes blood clots" and
- "If you had a choice of which vaccine you could get for COVID-19, which, if any would you choose?"
The results show that 17% of the public would now prefer to have the AstraZeneca–Oxford vaccine, a reduction from 24% reported in March. Twenty three percent of participants believe that the AstraZeneca-Oxford vaccine causes blood clots – an increase from 13% reported in March. A large difference was found in these beliefs when comparing data from before and after new MHRA guidance was issued on the COVID-19 vaccine; 17% of individuals interviewed in the first week of April believed there was a possible link between the vaccine and blood clots, which increased to 31% in the weeks following.
Reassuringly, this belief does not appear to have affected the overall level of confidence in vaccines. The survey found that 81% of participants believe vaccines are safe, compared to 73% reported in the Nov–Dec 2020 survey cohort. The percentage of individuals that strongly agree that this is the case has risen from 30% to 39%.
Eighty six percent believe that vaccines are effective (an increase from 79% reported in Nov–Dec 2020) and the percentage of those who feel this to strongly be the case is up from 38% to 47%.
“The blood clot scare has affected how some of the public view the AstraZeneca[–Oxford vaccine – but has not reduced confidence in vaccines overall. In fact, the trend has been towards increased commitment to get vaccinated – and quickly – as the rollout has progressed so well, with no sign of serious widespread problems. People have had more time and real-world experience to help them make up their minds," – Professor Bobby Duffy, director of the Policy Institute at King's College London and a researcher involved in the report said in a press release.
Siobhan McAndrew, senior lecturer in quantitative social science at the University of Bristol and another investigator in the study commented, "The public health challenge remains complex: to respond to the concerns and information needs of a diverse population, to support the pro-vaccine social norm, and to offer meaningful reasons to take up the vaccine to those who remain unconvinced."
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