BNT162b2 and ChAdOx1 SARS-CoV-2 Post-vaccination Side-Effects Among Saudi Vaccinees

Area of Science:

• Immunology
• Public Health
• Vaccinology

Background:

• Vaccination against SARS-CoV-2 is crucial for mitigating severe disease, hospitalization, and mortality.
• Both Pfizer-BioNTech (BNT162b2) and Oxford-AstraZeneca (ChAdOx1 nCoV-19) vaccines are widely administered globally and in Saudi Arabia.
• Understanding post-vaccinal side effects is essential for public health surveillance and vaccine confidence.

Purpose of the Study:

• To screen and compare local, systemic, and allergic post-vaccination reactions following BNT162b2 and ChAdOx1 nCoV-19 vaccines.
• To investigate the frequency and severity of side effects reported by vaccinees in Saudi Arabia.
• To identify potential cofactors influencing the severity of post-vaccinal reactions.

Main Methods:

• An online questionnaire surveyed vaccinees who received BNT162b2 (one or two doses) or ChAdOx1 (one dose).
• Data on local, systemic, and allergic reactions were collected and analyzed using cross-tabulation and Chi-square tests.
• The severity of reactions was assessed using ROC curve analysis, with cofactors like prior COVID-19 infection, age, sex, BMI, and comorbidities examined.

Main Results:

• A total of 4,170 individuals responded; 85.6% of BNT162b2 and 96.05% of ChAdOx1 vaccinees reported side effects.
• ChAdOx1 vaccinees experienced higher frequencies of both local and systemic side effects compared to BNT162b2 recipients.
• While BNT162b2 primarily caused mild side effects (63.92%), ChAdOx1 showed a more distributed pattern across mild (30.13%), moderate (28.62%), and severe (29.73%) categories. Palpitations and abnormal menstrual cycles were noted among reported systemic effects.

Conclusions:

• Both SARS-CoV-2 vaccines elicit post-vaccinal side effects.
• The Oxford-AstraZeneca (ChAdOx1) vaccine is associated with a higher frequency of systemic side effects compared to the Pfizer-BioNTech (BNT162b2) vaccine.
• Further research into specific side effect profiles, including less common events like abnormal menstruation and deep vein thrombosis, is warranted.