Vaccines are confirmed to be among the safest pharmaceutical products. And the role they have played over the years in reducing illnesses and deaths, especially among the most vulnerable people, clearly shifts the benefit-risk ratio in favor of vaccination. This is, in short, what emerged from the dossier published today by the Italian Medicines Agency (AIFA), which analyzed the reports of suspected adverse reactions to vaccines received in 2022, comparing them with data from previous years.
In detail, in 2022, approximately 19 million doses of vaccines were administered, excluding anti-Covid vaccines, which are the subject of other publications by AIFA. Well, the reports of suspected adverse reactions, collected by the Agency’s surveillance system, were just over 9 thousand, equal to 47.8 reports per 100 thousand doses, with a decrease of 39% compared to the previous year. Most of the reports, over 93.5%, concerned mild reactions. Those classified as serious are very few. If we consider only the reports of serious events, as underlined in the dossier, the reporting rate is reduced to 2.8 per 100 thousand doses administered, equal to 0.003% of total administrations.
Adverse reactions to vaccines: the vast majority are mild
The AIFA report, therefore, highlights that the vast majority (93.5%) of adverse events linked to vaccines are mild. These include: fever, local reactions at the injection site; crying; irritability, nervousness and restlessness; diarrhea, vomiting and stomach ache; generalized skin reactions, rashes, hives; drowsiness, headache and convulsions. The remaining 6.5% are classified as serious reactions, with 1.6% requiring hospitalization. Furthermore, most side effects resolve quickly: at the time of reporting, 78% of cases had already completely recovered, 8% were improving and only 0.7% were still recovering with after-effects. However, there is a 3% who had not yet recovered, while for the remaining 10% the final outcome had not been reported.
No causal link established with the deaths
The Aifa dossier found 7 deaths following the administration of the vaccine. “In no case did the available information allow us to identify the cause of death in the vaccine”, the Medicines Agency specified, recalling that the “evaluation of the causal relationship between an adverse event and the administration of a vaccine is a rather complex procedure. In fact, it is not enough for the event to occur after vaccination, but other possibilities must also be considered”.
Of the seven fatal cases, the vaccines indicated as suspect were in one case the quadrivalent against measles, mumps, rubella and chickenpox and in six cases the flu vaccine, in three reports administered together with the anti-Covid vaccine. Specifically, “the three cases of vaccination with only the flu vaccine indicated as suspect, involved elderly patients, with an average of 86.3 years, complex clinical pictures and multiple pathologies”. The remaining three cases of the flu vaccine co-administered with the anti-Covid vaccine “always involved patients with complex clinical pictures and multiple pathologies, aged 63, 80 and 92”. Instead, “the single case with the quadrivalent vaccine involved a 2-year-old patient, affected by multiple pathologies, whose death, as also reported by the medical-legal report, is not related to the vaccination but to the pre-existing pathological condition”.
The vaccines with the most reports
In 2022, as in the previous year, the highest reporting rates were for meningococcal C and meningococcal B vaccines. With regard to serious reactions only, the highest rate was observed for MMR (measles, mumps, rubella), MPRV-V (MMR plus varicella) and meningococcal C vaccines. However, the number of reports was significantly lower than in 2021.
As reported by AIFA, in 2022 at European level only two “safety signals” were identified that required further investigation by the Pharmacovigilance Risk Assessment Committee of the European Medicines Agency (EMA). The first concerned “extensive swelling of the limb after the administration of the 23-valent pneumococcal vaccine” and concluded with “the recommendation to update the product information”. The second concerned “immune thrombocytopenia (a lack of platelets in the blood) after the administration of the tetravalent vaccine against diphtheria, tetanus, pertussis and polio”. But since the available data “were not sufficient to support a hypothesis of a causal relationship between the vaccination and the pathology, no regulatory action was recommended by the Prac committee, other than routine monitoring”.
The risk-benefit ratio is all in favor of vaccines
“Vaccines are one of the main resources in terms of public and individual health, due to their significant impact not only on the prevention of numerous infectious diseases, but also on the general health of the population, with particular attention to the most fragile subjects, i.e. children, the elderly, chronically ill – commented the president of Aifa, Robert Nisticò -. All the more reason, the surveillance of adverse events that can be observed after vaccination is particularly rigorous”.
And he concludes: “Over time, vaccines have contributed to the significant reduction in morbidity and mortality, especially in frail subjects, and to the reduction in the spread of potentially lethal or disabling transmissible infectious diseases such as smallpox, with a consequent marked reduction in human, economic and social costs. All factors that, despite the alleged adverse events reported, tip the balance of the benefit-risk ratio clearly in their favor”.