Over 14,000 suspected adverse reactions to vaccines recorded

More than 14,000 suspected adverse reactions to Covid-19 vaccines have been recorded in Portugal, and there have been 82 reported cases of death in the elderly. Still, a cause-effect relationship has not been demonstrated, according to Infarmed.

According to the latest report by the National Authority for Medicines and Health Products, 14,447 adverse reactions (one per 1,000 administered vaccines) were reported until 31 August, most (7,581) referring to the Pfizer/BioNtech vaccine (Comirnaty), followed by AstraZeneca’s (Vaxzevria), with 4,188, Moderna’s (Spikevax), with 1,486, and Janssen’s, with 1,136 cases.

Infarmed stressed that this data does not allow a comparison of safety profiles between vaccines since they were used in distinct population subgroups (age, gender, health profile, among others) and distinct periods and epidemiological contexts.

Infarmed’s data indicates that for every thousand doses administered, one adverse reaction was reported in the case of Pfizer’s (Comirnaty), Moderna and Jansen vaccines. In contrast, in the case of AstraZeneca’s (Vaxzevria), the figure rises to two.

However, given the total number of vaccines administered, Infarmed said that adverse reactions are infrequent, with about one case in every thousand inoculations, a stable figure over time.

In the total of 14,664,616 doses administered, Infarmed recorded 14,447 cases of adverse reactions, of which 5,373 were serious (37.2%), including 82 cases of death among people with an average age of 77.

“The cases of death occurred in a group of individuals with a median age of 77 years and do not necessarily presuppose the existence of a causal relationship between each death and the vaccine, also occurring within the normal patterns of morbidity and mortality of the Portuguese population,” Infarmed said.

The report added that of the cases of adverse reactions classified as serious, about 90% relate to situations of temporary disability (including absenteeism from work) and others considered clinically significant by the notifier, whether a health professional or user.

By age group, the one with the most cases of serious adverse effects was the one between 25 and 49 years (2,536 cases), which also had the highest number of administered vaccines (5,052,411).

In the report, the Medicines Authority reports 17 non-serious cases of adverse effects in children under two years, justifying: “Regarding the cases in the age group of less than two years, these relate to non-serious occurrences of fever, regurgitation or irritability in children whose mothers may have been exposed to the vaccine.”

It also says that in the 12-17 age group, the 20 cases reported as serious mostly refer to situations already described in the vaccine information and that they are allergic-type reactions, which depend on the individual profile of the vaccinated person.

“They are cases that motivated observation and/or clinical treatment, but all had a positive evolution and without sequelae. Four of these cases were myocarditis cases,” it said.

In cases of severe reactions, Infarmed reported that three cases of thrombosis and thrombocytopenia were confirmed (two related to the Vaxzevria vaccine and one to Jansen), four considered probable, and five classified as possible.

The Medicines Authority also said that the Pharmacovigilance Risk Assessment Committee (PRAC) reviewed the available data and confirmed a possible statistical association between mRNA vaccines and the onset of myocarditis/pericarditis” and indicates that in Portugal, a further ten cases were reported as potentially associated with an mRNA Covid-19 vaccine (three confirmed, seven probable and one classified as “possible”).

Infarmed also reported one confirmed case of Guillain-Barré Syndrome (GBS) – an inflammatory disease of the peripheral nervous system – associated with the Janssen vaccine, four cases considered ‘probable’ (two potentially associated with the Janssen vaccine and two with Vaxzevria) and two other cases considered “possible” (Janssen).

It added that after assessing all the available data, the PRAC considered that a causal relationship between the Vaxzevria and Covid-19 Janssen vaccines and GBS is possible and that a causal relationship between GBS and the Comirnaty and Spikevax vaccines has not been identified.

It also recalled that the European Medicines Agency (EMA) has initiated a safety signal procedure to assess the degree of association between Covid-19 vaccines and the development of multisystemic inflammatory syndrome (MIS) in children or adults, and states that by 31 August one case, in a 16-year-old girl, associated with the Comirnaty vaccine, had been reported in Portugal.

“No relevant personal antecedents were known, and the absence of infection by SARS-CoV-2 was confirmed in the laboratory. The adverse reaction required hospital admission, but the patient is now stable and recovering,” it added.

The 10 most common reactions reported are cases of myalgia/muscular pain (3,044), headache/headache (3,534), pyrexia/fever (3,532), myalgia (muscle pain (3,481), pain at the injection site (2,999), fatigue (1,677), chills (1,494), nausea (1,339) and arthralgia/joint pain (1,084).

There were also cases of generalised pain (980), dizziness (854), general malaise (815), lymphadenopathy/ swollen lymph nodes (743), pain in body extremities (727) asthenia/body weakness (676) and vomiting (659).