Antibody responses after two doses of CoronaVac of the participants with or without the diagnosis of COVID-19

BACKGROUND CoronaVac, an inactivated whole-virion vaccine against COVID-19, has been shown to be safe with acceptable antibody responses by various clinical trials.
AIMS The objective was to investigate the post-vaccination antibody levels of both symptomatic and asymptomatic healthcare workers with or without the diagnosis of COVID-19 in an emergency department (ED) of a hospital serving as a pandemic hospital.
METHODS This single-centred, prospective study was conducted on 86 participants who were working as nurse or doctor in the ED. The volunteers were older than 18 years and either positive or negative for either computed tomography (CT), real-time reverse transcription polymerase chain reaction (qRT-PCR), or both. Thirty days after the second dose of CoronaVac (3 µg), the antibody levels were chemiluminescent microparticle immunoassay.
RESULTS Mean age of all participants were 33.1 ± 9.1 years. The antibody levels in the qRT-PCR( +) and CT( +) groups were significantly higher than the qRT-PCR( -) and CT( -) groups, respectively (p  CONCLUSION In conclusion, antibody responses of recovered patients COVID-19 diagnosed by both CT and qRT-PCR were much robust than the patients diagnosed by either one of the techniques or undiagnosed/disease-free participants suggesting that severity of the disease likely contributes to the antibody responses after vaccination with CoronaVac.

as reported in: Ir J Med Sci. 2022 Jan 10 [Epub ahead of print]