The Guardian view on the AstraZeneca vaccine: confidence from clarity
Every day, people take medicines with known side-effects. The risk is accepted when weighed against the benefit. But Covid vaccines are unfamiliar. There is no record of use over time to build public confidence. Still, they have been tested and proven to offer protection against the virus. By all usual medical standards, they are safe. That remains true for the AstraZeneca vaccine, despite an evolving picture that side-effects might include a rare blood clotting disorder.
The UK’s Medicines and Healthcare Products Regulatory Authority is still investigating the link, but has recommended, as a precaution, that other vaccines be preferred for recipients under 30. That is a notable shift in policy when ministers have dismissed any talk of risks associated with the jab. The European Medicines Agency on Wednesday recommended that bloodclotting be added to the list of “very rare” side-effects of the AstraZeneca vaccine; not sufficient to require a change in patterns of use.
According to the UK’s Joint Committee on Vaccination and Immunisation there were 30 cases of cerebral venous sinus thrombosis (CVST), including seven deaths, in the period up to 24 March, from a pool of 18 million people given the AstraZeneca jab. Those affected appear mostly to be women under 65, although the EMA concluded that age and sex were not determining factors in adverse reactions. The data set is growing daily. It is always feasible that guidelines regarding which vaccine is used for whom will change with new information. This is how science proceeds.
The chance of a severe reaction is probably no higher than 0.0001%. That is no comfort to those who are affected, but when it comes to public policy, statistical perspective matters. A very small number is not zero, but nor is it a reason to refuse vaccination.
The human mind is not good at processing risk. We pay disproportionate attention to rare events precisely because they are exceptional. Politics often exploits that cognitive weakness. Emotion and drama crowd out reflection and reason. That has been a hazard throughout the pandemic. It is especially problematic when it comes to reassuring audiences that might be wary of vaccines in general, and new ones in particular. It is not irrational to have questions about a medicine that did not exist a year ago. It is also not surprising that some minority communities respond warily to safety lectures from authorities that they mistrust through generations of discrimination.
There is an important distinction between vaccine hesitancy and malicious anti-vaccine misinformation that preys on hesitancy. Thankfully, the UK population has responded well to pro-vaccine advocacy, possibly because the NHS is a trusted institution. The more people get the vaccine, the more normal it becomes. A virtuous circle of confidence develops. One poll recently found UK respondents the most willing of any nation to be vaccinated – 78% saying they would gladly take a Covid jab – and with the highest rate of increase in positive views.
The mood could still change. The government must be respectful of public disorientation if regulators are calibrating their views. Concerns should not be dismissed glibly. It should be possible to tell people what side-effects and symptoms to be aware of without causing alarm. If the balance of risk and benefit is framed accurately, the evidence is irresistibly in favour of vaccination. Ministers must not fall into impatient, high-handed assertions of confidence. That tone can be counterproductive, as is boastfulness about the success of the UK’s vaccine programme.
Politicians like certainties; scientists prefer probabilities. The challenge with vaccines is accepting the existence of risk while keeping it in a proper perspective. Science has been a trusty guide so far. As long as the facts are communicated transparently, it should be possible to process new information and navigate risk without derailing public confidence.
• This article was amended on 8 April 2021 to change a reference to gender to sex.