Up to three-quarters of reported symptoms of the COVID-19 vaccines may not be entirely real, a new study suggests.
A research team from Harvard University performed a meta analysis on 12 previous studies that compared reported side effects to the Covid vaccines to those reported by people who instead received a placebo.
They found that 35 percent of placebo recipients reported an adverse event – something like a headache, fatigue or other symptoms – after receiving the first dose, and 32 percent did after the second.
Researchers found that 76 percent of ‘systemic’ adverse events after receiving the jab – symptoms that do not appear at the site of injection and instead affect other parts of the body – were likely either imagined or a result of something other than the shots.
They call this the ‘nocebo’ effect, when a person manifests or misattributes symptoms they are feeling to medicine or treatment they recently received.
These are usually symptoms a person is actually feeling, but misattributing to the vaccine, or just a result of anxiety they have over symptoms.
Researchers found that up to 76% of vaccine symptoms could be a result of the ‘nocebo’ effect, when a person imagines or misattributes issues to the jabs. The Harvard team performed a meta-analysis that included data from over 45,000 people – half of which received a Covid vaccine and half who received a placebo. They used data from the placebo group to adjust data from the vaccine group, and found that up to 76% of systemic symptoms like headaches of fatigue could be being misattributed
Researchers note that headaches and fatigue are the most common ‘nocebo’ symptoms, and are also the most widely publicized symptoms of the jab. They believe people’s anxiety over the symptoms could be the cause of them, or that people are feeling a headache of fatigued for another reason and just falsely blaming the jab. Pictured: A man in San Antonio, Texas, receives a shot of a COVID-19 vaccine
‘Though nocebo phenomena have been investigated in many contexts involving medication, evidence of their influence in vaccination remains scarce,’ researchers wrote.
‘However, a recent meta-analysis suggested that a significant proportion of placebo recipients in influenza vaccine trials experienced systemic AEs, such as headache or fatigue, owing to nocebo responses.’
The combined population of the study, which was published Tuesday in the JAMA Network Open, was 45,380. They were almost equally split between the vaccine and placebo groups.
Studies included in the analysis made up of data from all around the world, with the Pfizer-BioNTech, Moderna, Novavax, AstraZeneca and Johnson & Johnson vaccines all being included in the group.
Those in the vaccine group were more likely to report side-effects than those in the placebo group, with 46 percent reporting at least one systemic adverse effect, and 66 percent reporting a symptom at the injection site.
For comparison, 35 percent of people in the placebo group reported a systemic event, and 16 percent reported an adverse event at the injection site.
The most common adverse effect at the site of injection was arm pain, suffered by around ten percent of jab recipients. Just over nine percent of recipients reported tenderness of their arm as well.
A large portion of study participants reported feeling either headaches or fatigue as a result of the shot. Around 18 percent reported a headache while 16 percent reported feeling tired later.
Other systemic reactions include fever (0.3 percent of recipients), chills (three percent), malaise (eight percent), joint pain (seven percent), muscle pain (eight percent), nausea (three percent) or diarrhea (four percent).
Using this data, researchers can adjust the findings from the vaccine group according to findings from the placebo group.
They found that 76 percent of systemic adverse reactions in the vaccine group were likely the result of the nocebo effect, based of the findings from the placebo group.
Researchers note that headaches and fatigue are the most common nocebo symptoms. They are also the most publicized symptoms of the vaccine, while also not being very severe and feeling that a person can feel all the time.
Common nonspecific symptoms such as headache and fatigue, which the study’s findings showed to be particularly associated with nocebo, are listed among the most common AEs after COVID-19 vaccination in many information leaflets,’ researchers explained.
‘There is evidence that this sort of information may increase nocebo mechanisms such as AE-related anxiety and expectations. Furthermore, the information might cause a misattribution of commonly experienced nonspecific symptoms (eg, headache or fatigue) as specific AEs due to vaccination, even if these symptoms might have occurred in the absence of receiving any treatment.’
‘Thus, the current way of informing the public about potential vaccine AEs via leaflets and in the media may prompt or further increase nocebo responses.’