Prepared in a record nine months and developed with new technologies, vaccines against the new coronavirus are raising fears of short- and long-term side effects. Can the vaccines alter our genome? Do they contain dangerous adjuvants? Do they cause serious side effects?
Covid-19 vaccines have been developed in record time, as never before in the history of medicine. People are suspicious, especially since some of the vaccines about to be approved are based on technology that has never been tested before (RNA vaccines). According to several polls fear of side effects appears to be the second most important cause of anxiety, behind rushed clinical trials. Although side effects from vaccinations are relatively common, they are a good sign because they are evidence that they elicit an immune response.
Do RNA vaccines induce a change in the genome?
Many social network users wonder how RNA vaccines work, wondering if the RNA sequence can enter the cell and cause genetic changes. However, this is absolutely impossible. It is not gene therapy. Messenger RNA does not enter human DNA.
Messenger RNA technology does not allow the transcription of a genetic message. Therefore, it cannot be integrated into the host genome. This is one of the advantages of mRNA technology compared to DNA vaccines, which although much more stable and do not need to be stored at very low temperatures are less efficiently translated into RNA and then into proteins and in theory present the potential risk of integration into a host’s DNA.
Vaccines contain dangerous adjuvants
RNA (Pfizer, Moderna) or adenovirus (AstraZeneca and Johnson & Johnson) vaccines, which will be available first, do not require adjuvants. Adjuvants, however, are needed to improve the efficacy of conventional vaccines (inactivated vaccines or recombinant protein vaccines) by stimulating the innate immune response. Parts of the pathogen often do not contain the danger signals necessary to stimulate a strong immune response. Therefore, they must be supplemented with ‘synthetic danger signals’ called adjuvants.
Of the 13 Phase III vaccines, about half use an adjuvant such as aluminum salts, inulin, or squalene. These adjuvants can cause temporary side effects, such as redness and swelling at the injection site, muscle stiffness or pain, or even fever.
Vaccine side effects are common
According to published laboratory data, most side effects are predominantly mild to moderate and most commonly include fatigue, chills, pain or redness at the injection site, myalgias, headache, or even fever, although the frequency varies.
For example, in the Pfizer/BioNTech group, a local reaction is observed in 58.3% of patients after the first dose (compared to 22.2% in the placebo group). Fever occurred in 8.3% of patients after the second dose. The higher the dose received, the more severe the side effects. They are usually transient and disappear after a few days.
Only one case of a serious side effect (out of 20,000 people vaccinated) has been reported by AstraZeneca, namely temporary lower-limb paralysis. This is one of the accidents we see after vaccination, but they are very rare, usually, about 1 per 50,000 or 1 per 100,000.
Vaccines have long-term effects we don’t know about
Many people are reluctant to get vaccinated because they can’t assess the potential long-term effects of the vaccine. Because the Phase II and Phase III trials didn’t start until late July 2020 for the more advanced studies, there is, by definition, only a few months of follow-up. Serious events can occur up to six months after vaccination, and there may be very rare side effects that we will not see until a very large number of people have been vaccinated.
For example, during the 2010 H1N1 flu epidemic some cases of narcolepsy were observed in vaccinated individuals only four months after vaccination. Other vaccines have been suspected of causing multiple sclerosis or Guillain-Barré syndrome, but these diseases have never been proven to be due to the vaccines because of their rarity. This is an exception: according to most experts, most side effects, serious or not, occur within days or weeks after injection, meaning they have already been observed in the cases of the currently approved COVID-19 vaccines.
Like any drug, vaccines have side effects. The key is to do a risk-benefit analysis. So in the coming months, we all will have to choose between protecting ourselves, our loved ones, and the community from a highly contagious and deadly disease for a few days of inconvenience.