Is it true that vaccines against covid-19 have more side effects than any other?

In an online conference organised by the University of Mexico, a women identified as Karina Acevedo, an immunologist and researcher, quotes statements by Eric Caumes, head of infectious diseases from Pitié-Salpêtrière hospital in Paris, who claims that injections against covid-19 are the ones with “the highest rate of adverse effects in a vaccine”. This is misleading, although the physician indeed asserted it before knowing the definitive side effects of the vaccines, he later denied it himself.

"Professor Eric Caumes said by the end of December that although he was sure that vaccination is the only thing that will get us out of this situation, he had never seen a so high rate of adverse effects in a vaccine"

In the video, Acevedo shows an image of Eric Caumes, below which alleged declarations of the expert are written, in which, he apparently said that “although he was sure that vaccination is the only thing that will get us out of this situation, he had never seen a so high rate of adverse effects in the vaccine”. What Acevedo does not indicate is that such statements are in reality out of context: when the scientist mentioned the list of side effects, he was being based in a preliminary document of the possible adverse effects of Pfizer’s injection. Caumes himself explained it in a french television program, where he backed off himself a few days later, and after the publication of a scientific article in The New England Journal of Medicine (NEJM). By then the physician points out that such effects “are frequent but mild”.

Common reactions but without serious effects

“In general, it has been observed that all COVID-19 vaccines produce more side effects than other known vaccines. That is, they are classified as reactogenic vaccines”, indicates Adelaida Sarukhan, immunologist and scientific writer at the Institute of Global Health of Barcelona (ISGlobal, in Catalan), to Verificat. However, she adds, “the vast majority of these effects are mild —headache, muscle pain, fatigue, local cutaneous reactions, etc…— and they disappear after a couple of days”. 

In terms of more serious adverse effects, it is known that the one using messenger RNA —Pfizer and Moderna— have caused some serious allergic reactions (anaphylaxis), something that also occurs with other vaccines or drugs and are easy to identify and treat”, points out the expert. Massive vaccination with AstraZeneca and Janssen has revealed another adverse effect which is very rare, but more serious: cerebral thrombosis tied with a decrease of platelets.

Comparing the adverse effects of each vaccine is “very difficult”

Reactogenicity depends on many factors, such as the dose, the ingredients it carries, the administration form (simultaneous or combined) or the type of vaccine. For example, vaccines with attenuated viruses tend to be “more unstable, more difficult to produce, and more reactogenic”, than inactivated or dead virus vaccines, as reported by the Spanish Association of Vaccinology (AEV, in Spanish).

For this reason, the side effects can not be exactly compared. “A reactogenic vaccine is the one for diphtheria/tetanus in case of having received previous several doses”, points out to Verificat Antonio Navarro-Alonso, physician expert in Paediatrics, expert in covid-19 vaccination and one of the funders of AEV, who also cites the example for the herpes zoster (HZ/su) and flu, which can also be “particularly reactogenic in the first seasons when it is received”.

In the end, it could be affirmed that vaccines against SARS-CoV-2 are reactogenic but, according to Navarro-Alonso, “in general lines, they do not significantly differ from others that are systematically used in adults”.