Anxiety illness could undermine vaccine
The power of the mind to make people feel better is well documented. It’s called the placebo effect. It also works in reverse and is known as the nocebo effect. The Department of Psychological Medicine at Auckland University specialises in studying these effects. For instance, researchers in our department have shown that people listening to negative messages about the detrimental health effects of sound from windfarm turbine blades are more likely to report feeling sick, when in fact such sounds are common in our everyday environment and are generated by everything from the wind to traffic.
The nocebo effect poses a major problem for the distribution of any Covid-19 vaccine, because polls have consistently shown that there are a significant number of people in New Zealand and around the world who are worried over the safety of these vaccines. Just last year, the World Health Organisation reported that ‘‘vaccine hesitancy’’ was one of the top 10 greatest threats to global health.
Given the large number of people who are expected to be vaccinated, outbreaks of mass psychogenic illness can be expected, and when they do, they could have serious consequences by undermining public confidence.
In recent decades there have been at least a dozen documented cases of mass psychogenic illness triggered by vaccination campaigns around the world including in Iran, Italy, Jordan, India, Vietnam, Taiwan, Australia, Japan, the United States, Colombia, Denmark and Brazil. There are also many anecdotal media reports of similar reactions to vaccinations, that local health authorities deemed to have been triggered by anxiety. For instance, in 2000, a dozen girls in the UK fainted while being vaccinated for meningitis. Rumours quickly spread that they had been given a tainted batch. Closer examination revealed that a single allergic reaction had triggered psychogenic symptoms in the other anxious girls.
In 2014, Colombia was the scene of a vaccine scare involving more than 600 girls who had been injected with the human papillomavirus vaccine – commonly known as the HPV. Even after authorities had pinpointed the cause as anxiety, many parents refused to allow their girls to receive the second dose, placing them at higher risk of cervical cancer. A similar event took place in Vietnam in 2001, where after a psychogenic outbreak during a cholera inoculation campaign, just 2 of 97 affected children were allowed by their parents to receive a second dose, increasing their susceptibility to getting cholera and undermining public confidence in the vaccine nationwide.
So, what is the solution? Transparency and public awareness. There needs to be a greater awareness of the potential for psychological responses when taking any of the Covid-19 vaccines. The health community and the media need to know what psychogenic reactions will look like. The media have an important role to play here. Stories of vaccine side-effects can give the impression that they are more common than they are, and hence raise anxiety about the vaccine.
While individual adverse reactions will occur, they are rare, especially serious ones. We are confident that any vaccine that has been approved for widespread use by New Zealand authorities will have been shown to be safe and effective after undergoing large clinical trials, and we will line up to take it ourselves. But that does not mean it will be without adverse reactions.
So, what are the tell-tale indicators of a psychogenic event? These episodes should stand out as they will involve a clustering of transient, relatively minor symptoms. The most common symptoms from past psychogenic clusters include headache, nausea, dizziness, breathlessness, and fainting, with a rapid onset and quick recovery. If similar clusters emerge, by all means examine the quality of the batch, but mass psychogenic illness should be considered a prime suspect.
Mass psychogenic illness is more common than most people realise. It would be tragic if an event were to result in people deciding not to get vaccinated. In 1597, Francis Bacon wrote that ‘‘knowledge itself is power’’. It was good advice then, and it is good advice today.
We are confident that any vaccine that has been approved for widespread use by New Zealand authorities will have been shown to be safe and effective.