RESUMO
BACKGROUND: Selenium profile has been related with humoral immune response after vaccination, but evidence with regard to inactivated SARS-CoV-2 vaccine is lacking. OBJECTIVE: The current study aimed to examine the relationship between selenium profile and neutralizing antibody response to inactivated SARS-CoV-2 vaccine. METHODS: Plasma selenium and selenoprotein P concentrations, neutralizing antibody against the wild-type and Omicron variant were measured at baseline and at 14 days, 98 days after the third dose of inactivated SARS-CoV-2 vaccine. RESULTS: Neutralizing antibody against the wild-type and Omicron variant increased significantly after the third vaccination dose. Both higher plasma selenium and selenoprotein P were associated with increased neutralizing antibody against the wild-type strain at baseline. Moreover, higher plasma selenoprotein P was associated with increased neutralizing antibody against Omicron variant at baseline. However, nonsignificant association were observed after the third vaccine dose. CONCLUSION: Higher selenium profile was associated with neutralizing antibody response before the third dose of inactivated SARS-CoV-2 vaccine, but not after the third dose. Further prospective cohort studies are warranted to confirm our findings.