Risk of Waning Humoral Responses after Inactivated or Subunit Recombinant SARS‐CoV‐2 Vaccination in Patients with Chronic Diseases: Findings from a Prospective Observational Study in China

Heterogeneity of antibody responses has been reported in SARS‐CoV‐2 vaccination recipients with underlying diseases. We investigated the impact of the presence of comorbidities on the humoral response to SARS‐CoV‐2 vaccination in patients with chronic disease (PWCD) and assessed the effect of the number of comorbidities on the humoral response to vaccination. In this study, neutralizing antibodies (NAbs) and IgG antibodies against the receptor‐binding domain (RBD‐IgG) were monitored following a full‐course vaccination. In total, 1400 PWCD (82.7%, inactivated vaccines; 17.3%, subunit recombinant vaccine) and 245 healthy controls (65.7% inactivated vaccines, 34.3% subunit recombinant vaccine) vaccinated with inactivated or subunit recombinant SARS‐CoV‐2 vaccines, were included. The seroconversion and antibody levels of the NAbs and RBD‐IgG were different in the PWCD group compared with those in the control group. Chronic hepatitis B (odds ratio [OR]: 0.65; 95% confidence interval [CI]: 0.46–0.93), cancer (OR: 0.65; 95% CI: 0.42–0.99), and diabetes (OR: 0.50; 95% CI: 0.28–0.89) were associated with lower seroconversion of NAbs. Chronic kidney disease (OR: 0.29; 95% CI: 0.11–0.76), cancer (OR: 0.38; 95% CI: 0.23–0.62), and diabetes (OR: 0.37; 95% CI: 0.20–0.69) were associated with lower seroconversion of RBD‐IgG. Only the presence of autoimmune disease showed significantly lower NAbs and RBD‐IgG titers. Patients with most types of chronic diseases showed similar responses to the controls, but humoral responses were still significantly associated with the presence of ≥2 coexisting diseases. Our study suggested that humoral responses following SARS‐CoV‐2 vaccination are impaired in patients with certain chronic diseases.