Comparison of medium-term adverse reactions induced by the first and second dose of mRNA BNT162b2 (Comirnaty, Pfizer-BioNTech) vaccine: a post-marketing Italian study conducted between 1 January and 28 February 2021

Abstract

Objectives On 21 December 2020 the European Commission granted conditional marketing authorisation in the European Union for the anti-COVID-19 mRNA vaccine Bnt162b2 (Comirnaty, Pfizer/BioNTech). The main endpoint of this epidemiological, observational, prospective and monocentric study was to identify the number, types, and severity of adverse events following immunisation that occurred in subjects who had been previously infected with COVID-19, and in those who had not, after vaccination with Comirnaty, and to compare the two groups of subjects looking at events that occurred within a month after the first and the second dose. Methods Data were gathered by a questionnaire. The results included the responses of all healthcare workers (2030) of the IRCCS Sacro Cuore Don Calabria Hospital (Italy) vaccinated between 1st January and 28th February 2021. Adverse effects of the vaccine were reported after the first and the second doses. Results There was a statistically significant increase (p<0.001, χ 2 =35.60) in participants who experienced some side-effects after receiving the first dose of the vaccine and who had previously been infected with the coronavirus, compared with participants who had not previously been infected. 46.76% (136) of the participants who had previously been infected experienced some side-effects after the first dose of vaccine, and 63.23% (184) experienced some sideeffects after the second dose, compared with 29.15% (507) after the first dose and 70.79% (1231) after the second dose in those who had not been previously infected. The number of participants who experienced side-effects after the second dose and had previously been infected was significantly lower compared with participants who had not previously been infected (p=0.0094, χ 2 =6.743). Conclusions Most of the side-effects identified in this trial were also reported by the manufacturer and the US Food and Drug Administration. Active surveillance should always continue to constantly check the vaccine's risk/ benefit ratio over time.

Side Effects of COVID-19 Pfizer-BioNTech mRNA Vaccine in Children Aged 12–18 Years in Saudi Arabia

“…Published literature showed that side effects were more prevalent in females than in males and in people aged 55 years or younger than in those older than 55 years [22][23][24]. Similarly, our data also showed that in children between 12-18 years, female participants reported more side effects than males.…”

“…Pain/redness at the injection site (90%), fatigue (67%), fever (48%), and headache (55%) were the most frequently reported side effects by the study participants (Figure 1). The data from the present study are in support of the data from clinical trials as well as other real-world studies [20][21][22][23][24]. For example, in phase 3 clinical trials of the BNT162b2 vaccine, the three most common events after the first dose were injection-site pain (71-83%), fatigue (34-47%), and headache (25-42%) [21].…”

“…This may result in misidentification of less frequent adverse events [20]. The rapid development of COVID-19 vaccines due to the urgency of the pandemic and the implementation of a newly emerging technique for vaccine development (i.e., mRNA vaccine) have led to some concerns regarding potential side effects [24][25][26][27][28]. Although several reports have been released on the safety and effectiveness of vaccines against SARSCoV-2, real-world data on the safety of this novel messenger RNA (mRNA)-based COVID-19 vaccine, particularly in children, are still scarce.…”

Active Surveillance of Adverse Events in Healthcare Workers Recipients After Vaccination with COVID-19 BNT162b2 Vaccine (Pfizer-BioNTech, Comirnaty): A Cross-Sectional Study

“…Nevertheless, this condition was not included in the final multivariate model and should be further investigated comparing convalescent COVID-19 cases and controls. In a study [ 37 ], a significant increase of adverse events after vaccination was observed amongst individuals who had previously been infected compared with those who had not, and the number of previously infected subjects who experienced side-effects after the second dose was lower compared with those who were not previously infected. Similar conclusions were observed elsewhere [ 38 ] because infected subjects had higher risk of moderate systemic symptoms after the first dose as compared to individuals naive to the virus and showed a lower risk after the second dose.…”

To Be or Not To Be Vaccinated: That Is a Question in Myasthenia Gravis

“…The usual post-vaccination observation time that lasts 15-30 minutes does not fully capture the AEs that may appear 1-2 weeks after vaccination (108). Both patients and clinicians should carefully monitor AEs since those who had previously been COVID-19 infected might experience AEs after first doses, and who had not been infected could get AEs after the second dose (124).…”