Antibody response and self-reported adverse reactions following vaccination with Comirnaty: a pilot study from a Croatian university hospital

Abstract

This study aimed to determine antibody responses against SARS-CoV-2 spike (S) after both BioNTech–Pfizer Comirnaty vaccine doses and study the correlation with self-perceived adverse reactions. Antibodies determination with Elecsys anti-SARS-CoV-2 S assay was performed a day prior to or just before administration of the second dose and 8–13 days after the second dose. Participants selected from a predefined list of the experienced local (injection site reactions) and/or systemic (fatigue, headache, myalgia, arthralgia, chills and fever) post-vaccination adverse reactions. An average 100-fold increase in antibody titre in naive vaccinees was observed between the two time points (median 67 U/mL vs 2841 U/mL, p<0.001). Participants aged below 50 had higher antibody titres (median 99 U/mL vs 26 U/mL, p=0.003 after the first dose; median 3617 U/mL vs 2556 U/mL, p=0.026 after the second dose). All reported adverse reactions were mild-to-moderate, with more participants declaring systemic reactions after the second dose (p=0.001), without a clear correlation with antibody titre.

Adverse Reactions to Anti-SARS-CoV-2 Vaccine: A Prospective Cohort Study Based on an Active Surveillance System

“…The only exception was the study conducted by Menni et al, where local ARs following the first dose (71.9%) were more frequent than the second dose (68.5%, p < 0.0001) [6]. As reported by others, the main reason for the highest frequency of ARs after the second dose is the strengthening of the immune response against SARS-CoV-2, [1,26] leading to a generalized inflammatory status, involving humoral and cellular immunity [1] In detail, as well as empowering the antibody responses [1,26,27], the completed vaccination schedule increased also interferon γ (INF-γ) and other pro-inflammatory cytokine levels [1,27] which could be responsible for the onset of most systemic ARs due to a damage of local tissues. [1] During the immune activation after BNT162b2 vaccination, other cytokines as interleukin-2 (IL-2) were secreted [7,27].…”

“…Their participation to this study might decrease the median age of the overall recruited persons (36 years old). Whatever the age of vaccinated people, the literature showed increased immune reactions among younger individuals [ 1 , 26 ]. This was confirmed also by the National Pharmacovigilance Network during the period between 27 December 2020 and 26 April 2021 [ 10 ].…”

“…A reason could be the stronger immune response among younger subjects, showing generally higher antibody titles and cytokines levels [ 27 ]. On the other hand, the senescence of the immune system determined a reduction in immune responses after vaccination in the elderly [ 1 , 26 ]. Furthermore, several findings had found an impaired development of antibody response among elderly subjects due to a lower IL-2 levels.…”

“…Furthermore, several findings had found an impaired development of antibody response among elderly subjects due to a lower IL-2 levels. This condition [ 34 ] might decrease the risk for ARs [ 1 , 26 ].…”

Association between IgG antibody levels and adverse events after first and second Bnt162b2 mRNA vaccine doses

“…Older age, male gender, and immunosuppression were shown to be risk factors for lower antibody levels [4,5]. Little is known about the correlation between postimmunization serology levels with the type, number, and severity of adverse events [6]. In order to curtail COVID-19 morbidity, some countries (including Israel) have already begun J o u r n a l P r e -p r o o f offering a third [7] and even a fourth dose.…”