RESUMO
There is still controversy about whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination at different times of day will induce a stronger immune response. Therefore, a randomized controlled trial (ChiCTR2100045109) is conducted to investigate the impact of vaccination time on the antibody response to the inactivated vaccine against SARS-CoV-2 from April 15 to 28, 2021. Participants are randomly assigned in a 1:1 ratio to receive inactivated SARS-CoV-2 vaccine in the morning or afternoon. The primary endpoint is the change of neutralizing antibody between baseline and 28 days after the second dose. In total, 503 participants are randomized, and 469 participants (238 in the morning group and 231 in the afternoon group) complete the follow-up. There is no significant difference in the change of neutralizing antibody between baseline and 28 days after the second dose between the morning and afternoon groups (22.2 [13.2, 45.0] AU mL-1 vs 22.0 [14.4, 40.7] AU mL-1 , P = 0.873). In prespecified age and sex subgroup analyses, there is also no significant difference in the morning and afternoon group (all P > 0.05). This study demonstrates that the vaccination time does not affect the antibody response of two doses of inactivated SARS-CoV-2 vaccine.
RESUMO
Background: The safety of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines is widely appreciated. However, there is limited knowledge regarding the potential impact of SARS-CoV-2 vaccines on the thyroid. Methods: We performed two prospective clinical trials between April and June, 2021, enrolling recipients of the inactivated SARS-CoV-2 vaccine (BBIBP-CorV and CoronaVac). Thyroid function, antithyroid antibody levels, and SARS-CoV-2 neutralizing antibody levels were detected for each participant before receiving the first vaccine dose and 28 days after receiving the second vaccine dose. Results: A total of 657 recipients participated in the study. The overall median thyroid function and levels of antithyroid antibodies before and after SARS-CoV-2 vaccination were within the normal range. Among the 564 participants with normal thyroid function at baseline, 36 (6.38% [confidence interval; CI 4.51-8.73]) developed thyroid dysfunction. Of the 545 recipients with negative antithyroid antibodies at baseline, none developed abnormal antibodies after vaccination. Notably, 75.27% (70/93 [CI 65.24-83.63]) of the 93 recipients with thyroid dysfunction returned to normal function after vaccination. The levels of antithyroid peroxidase antibody (96.20% [CI 89.30-99.21]) and antithyroglobulin antibody (TgAb; 88.31% [CI 78.97-94.51]) remained positive after vaccination in most patients with abnormal values at baseline. However, the TgAb levels in more than half of the patients (48/77) decreased. All of 11 abnormal thyrotropin receptor antibody levels at baseline decreased postvaccination. Conclusions: Vaccination with an inactivated SARS-CoV-2 vaccine had no significant adverse impact on thyroid function or antithyroid antibodies within the first 28 days after the second dose. Clinical Trial Registration: ChiCTR2100045109 and ChiCTR2100042222.