ABSTRACT
ObjectiveWe aimed to determine the relationship between vaccine-related adverse effects and antibody (Ab) titers from 3 to 6 months after the second dose of the BNT162b2 coronavirus disease 2019 (COVID-19) mRNA vaccine (Pfizer/BioNTech) in Japan. MethodsWe enrolled 378 healthcare workers (255 women, 123 men) whose Ab titers 3 and 6 months after the second dose were analyzed in our previous study and whose characteristics and adverse effects were collected previously using a structured self-report questionnaire. ResultsMedian age was 44 years. While injection-site symptoms occurred with almost equal frequency between the first and second doses, systemic adverse effects, such as general fatigue and fever, were significantly more frequent after the second dose than after the first. Multivariate analysis showed that fever was significantly correlated with female sex for the second dose (odds ratio [OR], 2.139; 95% confidence interval [95%CI], 1.185-3.859), older age for the first dose (OR, 0.962; 95%CI, 0.931-0.994) and second dose (OR, 0.957; 95%CI, 0.936-0.979), and dyslipidemia for the first dose (OR, 8.750; 95%CI, 1.814-42.20). Age-adjusted Ab titers at 3 months after vaccination were 23.7% and 23.4% higher in patients with fever than in those without fever after first and second dose, respectively. In addition, age-adjusted Ab titers at 3 and 6 months after the second dose were respectively 21.7% and 19.3% higher in the group with anti-inflammatory agent use than in the group without anti-inflammatory agent use. ConclusionParticipants with systemic adverse effects tend to have higher Ab titers from 3 to 6 months after the second dose of the BNT162b2 vaccine. Our results may encourage vaccination, even among people with vaccine hesitancy related to relatively common systemic adverse effects.
ABSTRACT
ObjectiveWe aimed to determine antibody titres at 6 months and their rate of change during 3-6 months after the second dose of the BNT162b2 coronavirus disease 2019 (COVID-19) mRNA vaccine (Pfizer/BioNTech) and to explore clinical variables associated with titres in Japan. MethodsWe enrolled 365 healthcare workers (250 women, 115 men) whose 3-month antibody titres were analyzed in our previous study and whose blood samples were collected 183 {+/-} 15 days after the second dose. Participant characteristics collected previously were used. The relationships of these factors with antibody titres at 6 months and rates of change in antibody titres during 3-6 months were analyzed. ResultsMedian age was 44 years. Median antibody titre at 6 months was 539 U/mL. Older participants had significantly lower antibody titres (20s, 752 U/mL; 60s-70s, 365 U/mL). In age-adjusted analysis, smoking was the only factor associated with lower antibody titres. Median rate of change in antibody titres during 3-6 months was -29.4%. The only factor significantly associated with the rate of change in Ab titres was not age or smoking, but sex (women, -31.6%; men, -25.1%). ConclusionThe most important factors associated with lower antibody titres at 6 months were age and smoking, as at 3 months, probably reflecting their effect on peak antibody titres. However, antibody titres significantly attenuated during 3-6 months in women alone, which reduced the sex difference in antibody titres seen during the first 3 months. Antibody titres may be affected by different factors at different time points.
ABSTRACT
ObjectiveWe aimed to determine antibody (Ab) titres 3 months after the second dose of the BNT162b2 coronavirus disease-2019 (COVID-19) vaccine and to explore clinical variables predicting these titres in Japan. MethodsWe enrolled 378 healthcare workers (255 women, 123 men) whose blood samples were collected 91{+/-}15 days after the second of two inoculations of the BNT162b2 COVID-19 mRNA vaccine (Pfizer/BioNTech) given 3 weeks apart. Medical histories and demographic characteristics were recorded using a structured self-reported questionnaire. The relationships between Ab titres and these factors were analysed. ResultsMedian age (interquartile range [IQR]) of the participants was 44 (32-54) years. Median Ab titre (IQR) against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike antigen was 764 (423-1140) U/mL. Older participants had significantly lower Ab titres; median (IQR) Ab titres were 942 (675-1390) and 1095 (741-1613) U/mL in men and women in their 20s, respectively, but 490 (297-571) and 519 (285-761) U/mL in men and women in their 60s-70s, respectively. In the age-adjusted analysis, the only risk factors for lower Ab titres were male sex and smoking. However, the sex difference may have arisen from the sex difference in smoking rate. Moreover, Ab titres were significantly lower in current smokers than in ex-smokers. ConclusionThe most important factors associated with low Ab titres were age and smoking habit. In particular, current smoking status caused lower Ab titres, and smoking cessation before vaccination may improve the individual efficacy of the BNT162b2 vaccine.
