Gender Differences in Adverse Events Following the Pfizer-BioNTech COVID-19 Vaccine.

Area of Science:

• Vaccinology
• Immunology
• Public Health

Background:

• Adverse events following COVID-19 mRNA vaccines range from mild to severe.
• Detailed age-specific gender differences in vaccine adverse effects are not well-documented.

Purpose of the Study:

• To investigate age and gender differences in adverse events following the Pfizer-BioNTech COVID-19 vaccine.
• To analyze gender-specific risks for local, systemic, and sensory adverse events.

Main Methods:

• Utilized data from four cross-sectional studies, including national adverse event databases and workplace surveys.
• Analyzed age and gender-disaggregated reports for individuals receiving two or three doses of the vaccine.
• Calculated female-to-male risk ratios (RRs) for various adverse events.

Main Results:

• Adverse event risks were higher after the second vaccine dose and consistently higher in females across all age groups.
• Females reported increased risks for local (e.g., injection site pain), systemic (e.g., fever), and sensory (e.g., paresthesia) events.
• Female-to-male RRs for combined adverse reactions exceeded 1.8 in one study and 3.0 in another, particularly for events like shivering, muscle pain, fatigue, and headaches.

Conclusions:

• Consistent excess of adverse events in females suggests a need for gender-specific assessment and reporting of mRNA vaccine side effects.
• Gender differences in adverse event profiles should be considered when establishing vaccine dosing schedules.