Comparison of the duration of viral RNA shedding and anti-SARS-CoV-2 spike IgG and IgM antibody titers in COVID-19 patients who were vaccinated with inactivated vaccines or not: a retrospective study

Background At present, the role of inactivated vaccines in viral RNA shedding among Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) breakthrough infections is still unknown. Methods We collected data of 147 coronavirus disease 2019 (COVID-19) patients with mild-to-moderate illness who were hospitalized in the Third People's Hospital of Yangzhou from 7 to 20 August 2021 and analyzed the differences in symptoms and laboratory tests among fully vaccinated (FV), partially vaccinated (PV) and unvaccinated (UV) patients. Results The median duration of viral RNA shedding was shorter in the FV (12 [IQR, 9.5-14] days) and PV (13 [IQR, 9-16.75] days) groups than in the UV group (15 [IQR, 11.75-17.25] days) (adjusted P < 0.001 and adjusted P = 0.23, respectively). The median titers of SARS-CoV-2-specific IgG and IgM were significantly higher in the FV (12.29 S/co [IQR, 2.08-63.59] and 0.3 S/co [IQR, 0.05-2.29], respectively) and PV (0.68 S/co [IQR, 0.14-28.69] and 0.12 S/co [0.03-5.23], respectively) groups than in the UV group (0.06 S/co [IQR, 0.03-0.47] and 0.04 S/co [IQR, 0.02-0.07]) (adjusted P < 0.001 and adjusted P = 0.008, respectively). Conclusions Inactivated vaccines may shorten viral RNA shedding in breakthrough infected patients who have mild-to-moderate illness and may improve the ability of the host to generate specific antibodies to infection.