Several studies reported that the severe acute respiratory syndrome coronavirus-2 antibody levels change over 6 months in participants receiving the vaccination. For the enrolled 272 healthcare workers (HCWs), blood samplings were performed at 2, 16, and 24 weeks after the second vaccination dose. In the 267 non-infected HCWs, the neutralizing antibodies decreased by 23.9%, and the anti-spike/receptor binding domain antibody decreased by 53.8% at 24 weeks. We observed no significant difference in antibody reduction between the sexes; however, in younger individuals, there was higher antibody formation and lower reduction rates of the neutralizing antibody. In 3 HCWs with breakthrough infections, the antibody le... More
Several studies reported that the severe acute respiratory syndrome coronavirus-2 antibody levels change over 6 months in participants receiving the vaccination. For the enrolled 272 healthcare workers (HCWs), blood samplings were performed at 2, 16, and 24 weeks after the second vaccination dose. In the 267 non-infected HCWs, the neutralizing antibodies decreased by 23.9%, and the anti-spike/receptor binding domain antibody decreased by 53.8% at 24 weeks. We observed no significant difference in antibody reduction between the sexes; however, in younger individuals, there was higher antibody formation and lower reduction rates of the neutralizing antibody. In 3 HCWs with breakthrough infections, the antibody levels were relatively low just before the coronavirus disease 2019 infection. In conclusion, as antibody titers decrease over time after the second vaccination dose and HCWs with low antibody titers tend to have a high probability of breakthrough infection, an additional dose should be considered after several months.
