The Medicines Department has published a list of the most common side effects of the new Pfizer/BioNTech coronavirus vaccine, which is likely to be the first to receive marketing authorization in the European Union.
Both the Pfizer and Moderna vaccines use a new immunization technology based on so-called matrix or information ribonucleic acid (mRNA or mRNA). Traditional vaccines use a weakened or dead virus to stimulate the body’s immune system, while lab-created mRNA instructs cells to produce the coronavirus’s spike proteins. Unlike the actual virus, these proteins trigger an immune system response without reproducing the virus.
Matrix ribonucleic acid was discovered back in the early 1960s, but scientists had long been unable to overcome obstacles such as the instability of mRNA in the body and its tendency to cause inflammatory reactions. A breakthrough came around 2005 when Hungarian scientist Katalin Kariko, now a senior vice president at BioNTech, found a way to deliver mRNA without overwhelming the immune system.
Generally, a vaccine is considered good if it is at least 60% effective. However, the Pfizer vaccine has a significantly higher rate: 96.5% in people under 55 years of age and 93.7% in people over 55 years of age. The average effectiveness is 95%. Since the vaccine has not been tested on children, it will not be administered to children.
To achieve the promised efficacy, the vaccine is administered in two doses 21 days apart, with final efficacy occurring seven days after the second dose. Some immune protection appears after the first dose, but it is not sufficient.
It is not yet known exactly how long the immune protection lasts, and the studies indicate a two-month period. Long-term effectiveness (one or two years) cannot be tested at this time, simply because so little time has passed since the vaccine was administered to participants in clinical trials. However, scientists will continue to monitor the effectiveness of the vaccine over time to eventually establish this figure as well.
Side effects
According to the report, the Pfizer vaccine was found to have the most typical side effects that occur with vaccination: pain at the injection site, increased body temperature, fatigue, headache, nausea and diarrhea. In those people who experienced these adverse events after vaccine administration, they usually resolved within two days. They were also alleviated by pain tolerance.
In the case of rare severe side effects, the incidence of the condition is compared to the incidence of the condition in the general population, looking at whether the incidence is higher or lower than in the general population.
In addition, the efficacy of Pfizer’s vaccine for certain diseases has not yet been established because the number of people with these diseases during the clinical trials was insufficient to draw generalizable conclusions.
The vaccine manufacturer is obliged to continue monitoring and reporting side effects in order to identify possible adverse events that have not been previously reported. The European Medicines Agency will conduct such monitoring and produce interim reports.
In addition, all vaccines are independently evaluated in laboratories of the medicines regulators in the EU Member States before they are authorized for sale in the EU. This verification is done for each vaccine lot and each vaccine as part of the standard procedure.