Evaluation of increased antibody titer COVID-19 after astrazeneca vaccination based on the age at UTA'45 Jakarta Vaccine Center

Background: Vaccine is an essential tool to limit the health of the COVID-19 pandemic. AstraZeneca vaccine already provided promising effectiveness data. Still, the study must check the correlation between vaccination and antibody titer. Aim: This study aims to evaluate antibody titer after AstraZeneca vaccination based on the age group. Materials and Methods: This study used a prospective cross-sectional method with convenience sampling. Inclusion criteria were all Indonesian citizens above 18 years old who were vaccinated at UTA'45 Jakarta Vaccine Center with no history of COVID-19 before the vaccination and had filled up the informed consent. Results: This study's total sample was 102 females; 51.90%, residents of Java Island; 91.17% had comorbidities; 50,98%, smokers; 9,80%, alcohol drinker; 9,80%, exercise; 80,39%, blood pressure; 128/73, SpO2: 97,82. Most participants aged around 30 years had a body mass index of 23.33. Age, comorbidity, smoking, alcohol, and exercise habit significantly correlate with the increase of the participants' antibodies (P < 0.001). The age shows that the younger the participant, the higher the titer antibody 2 will be (P = 0.001, 95% confidence interval [CI], −1.935, −0.694). The exercise shows that the participant with the routine practice will have a higher titer antibody 2 (P = 0.002, 95% CI, 12.016, 51.791). Antibody titer for participants younger than 35 years old increased 5.7 times while for participants between 35 and 45 years old was 3.9 times. Another group (>45–55 years old) has shown an improvement in antibody titer at 1.7 times, but the last group (>55 years old) described an increase in antibody titer at 232.3 times. Conclusions: Age, comorbidity, smoking, alcohol, and exercise contributed to the increase in titer antibody 2 value of the AstraZeneca vaccine participants. Participants in the age group <35 years have an excellent immune system.