serial of neutralizing antibody at 2, 4, 6, 9, 12 month after COVID-19 vaccination 1) semi-quantitative measurement of neutralizing antibody at 2, 4, 6, 9, 12 month after COVID-19 vaccination 2) investigate the duration maintaining acceptable range (over 30% inhibition)~investigate the factors on antibody titer at 2 month after vaccination 1) potential factors: age, sex, body weight, height, use of medication, use of antipyretics (NSAID or tyrenol), side effect of COVID-19 vaccination 2) correlation between antibody titer and potential factors~Compare 4 diagnostic ELISA kit at 2 month after vaccination 1) measure neutralizung antibody using ELISA kits from 4 different companies 2) investigate correlation coefficient of antibody titer between companies
serial of neutralizing antibody at 2, 4, 6, 9, 12 month after COVID-19 vaccination~investigate the factors on antibody titer.