AIFA report on vaccines: adverse event reports down 86%

The Italian Medicines Agency (AIFA) has published the 2023 Vaccine Report , the document that reports on suspected adverse reactions to vaccinations, with a focus on Covid-19 prophylaxis that takes stock of over 2 years of post-authorization monitoring. Well: the data show a drastic drop in alerts, bringing the levels to values ​​below those recorded in the pre-pandemic period.

“In 2023 - it is written - there was a marked reduction in reports from vaccines (-86.3%), which went from 31,652 to 4,330. Approximately 1 in 3 reports in 2023 concerned anti-Covid vaccines (28.3%, 1,224), for which the decrease compared to 2022 was equal to 94.2%”. If we exclude reports on anti-Covid prophylaxis, the reduction corresponds to 71.1%, with a total of reports going from 10,967 in 2022 to 3,164 in 2023.

Reports of serious events decreased by 83%

73.6% (3,185) of all reports (including Covid-19 vaccines) concerned non-serious adverse events. The remaining 26.4% (1,145) instead concerned reports with at least one serious adverse event: among these, in the majority of cases it was “other clinically relevant condition” (14.8%, 641) or “hospitalization or prolongation of hospitalization” (6.3%, 272). Compared to 2022, reports with at least one serious event decreased by 83%, going from 6,774 to 1,145.

The reasons for the reduction

According to Aifa, three main reasons can explain this drastic decrease in reports. The first is the collapse of doses administered, which went from over 52 million in 2022 to just over 25 million in 2023. Furthermore, the large active pharmacovigilance projects have ended and media interest has decreased "which - the Agency reports - historically pushes up spontaneous reports for all vaccines".

Focus on Covid vaccines

In the dossier dedicated to anti-Covid vaccines, it is stated that "the reporting rate was 2.5 per 100 thousand doses administered. "For comparison - reports Aifa - the rate of hospitalization from Covid in 2023 was 140 per 100 thousand inhabitants. The risk of the disease remained largely higher than that of the vaccine. It also emerges that "compared to the reports regarding all the other vaccines, for anti-Covid vaccines there is a lower proportion of those sent by doctors (30.4%) and especially by other healthcare workers (8.9%), while there is a significant percentage of reporting by citizens, equal to 45.4% ".

The 9 open safety signals and the confirmation of the benefit/risk ratio

In 2023, 9 safety signals were opened for anti-Covid vaccines: "All were examined by the Prac, the Risk Assessment Committee of the EMA, the European Medicines Agency. And all were closed favorably, that is, without any change to the authorization or clinical indications of the vaccines involved. Before 2023, other safety signals evaluated by the EMA's Prac concluded by confirming the benefit-risk ratio in favor of the vaccine, however highlighting a correlation between the adverse events and its administration. This has already led to the inclusion of adverse effects in the package leaflet, as is the case for any other drug. The related adverse events, but not to such an extent as to outweigh the benefits of vaccination for the general population, are: anaphylactic reaction, capillary leak syndrome, embolic and thrombotic events, erythema multiforme, heavy menstrual bleeding, immune thrombocytopenia, localized swelling in people with a history of dermal filler injections, myocarditis and pericarditis".

Other signals evaluated

"Among the signals evaluated by the Prac - we read in the Report - but closed without modifying the information sheets because the data were not sufficient to support a causal association, there are: acute external macular retinopathy, amenorrhea, autoimmune hepatitis, corneal transplant rejection, glomerulonephritis and nephrotic syndrome, histiocytic necrotizing lymphadenitis, myositis, multisystem inflammatory syndrome, pemphigus and pemphigoid (blisters in the upper and lower part of the epidermis), postmenopausal hemorrhage, vulvar ulceration".

Cause-effect relationship not proven

As Aifa reminds us, the reports are not certainty of a cause-effect relationship between the administration of a vaccine and the reported adverse event. “The temporal association between vaccination and the adverse event must also be biologically plausible (for example, if a tumor is diagnosed 3 days after the administration of a vaccine, it is unlikely that the responsibility is attributable to the vaccination)”. It is also necessary to consider “the frequency with which that event occurs in the general population, regardless of vaccination; and also the presence of other possible causes, such as pre-existing diseases and medications taken”.

Serious events associated with anti-Covid vaccines

In 2023, the report continues, there were 572 reports with at least one serious event associated with anti-Covid vaccines (46.7% of the total reports on these vaccines). But, he warns, even in this case "it does not mean that the vaccine caused the event. It only means that, in those cases, the reported event had a significant clinical impact (hospitalization, risk to life, temporary or permanent disability). In reality - he points out - only 182 reports out of 1,224 concerned adverse events that arose in 2023. The others (over 1,000) were retroactive, that is, reports referring to previous years. And it is precisely among these that the most serious events are concentrated: an understandable logic, since the milder reactions are often overlooked or forgotten over time, while the serious ones tend to push users to report even months later".

The results

Regarding the outcomes of these events, in almost half of the cases (49%) there was a complete resolution or improvement. In 31.4% the outcome at the time of reporting was considered unresolved; in 7.8% it was resolved with sequelae and in 2.6% death was reported: "Those following the administration of the anti-Covid vaccines alone were 36, while 2 were cases of co-administration of the anti-Covid and flu vaccines. This does not mean, however, in any case - specifies the AIFA - that a causal link was found between the administration of the vaccine and the death. In 11 cases, in fact, essential information for the evaluation was missing, in others the evidence did not support any causal association with the vaccine. In 7 cases, these were patients with a complex clinical picture, with the coexistence of important diseases, while for another 7 cases, death occurred many months after the administration of the vaccine, a fact that does not suggest any temporal correlation with the last administration. For another case, it was the report of the family's medical examiner that excluded any connection between the vaccination and the death, most likely resulting from a suspected encephalitis that was not promptly diagnosed. A final case involved an elderly patient, struck by anaphylactic shock a few minutes after the administration of the fourth dose of the vaccine”.

Confirmation of overall safety

The report goes into detail about the 9 signals opened in 2023 and reiterates that in all cases "sufficient evidence has never emerged to establish a causal link between the vaccine and the adverse events that are the subject of the signal, a threshold of evidence has never been reached that calls into question the overall safety of the vaccine. No signal has required the recall of batches, the modification of the therapeutic indications, or the interruption of administrations".