Immunogenicity and safety of the CoronaVac inactivated SARS-CoV-2 vaccine in people with underlying medical conditions: a retrospective study (preprint)

Background: People living with chronic disease, particularly seniors older than 60 years old, are lagging behind in the national vaccination campaign in China due to uncertainty of safety and effectiveness. However, this special population made up of most severe symptom and death cases among infected patients and should be prioritized in vaccination program. In this retrospective study, we assessed the safety and immunogenicity of the CoronaVac inactivated vaccines in people with underlying medical conditions to address the vaccine hesitation in this special population. Methods: In this cohort study, volunteers aged 40 years and older, had received two doses of CoronaVac inactivated vaccines (3-5 weeks interval), been healthy or with at least one of the six diseases: coronary heart disease (CAD), hypertension, diabetes mellitus (DM), chronic respiratory disease (CRD), obesity and cancer, were recruited from 4 study sites in China. The primary safety outcome was the incidence of adverse events within 14 days after each dose of vaccination. The primary immunogenic outcome was geometric mean titer (GMT) of neutralizing antibodies to living SARS-CoV-2 virus at 14-28 days, 3 months, and 6 months after full two-dose vaccination. This study is registered with ChiCTR.org.cn (ChiCTR2200058281) and is active but no longer recruiting. Findings: Among 1,302 volunteers screened between Jul 5 and Dec 30, 2021, 969 were eligible and enrolled in our cohort, including 740 living with underlying medical conditions and 229 as healthy control. All of them formed the safety cohort. The overall incidence of adverse reactions was 150 (20.27%) of 740 in the comorbidities group versus 32 (13.97%) of 229 in the healthy group, with significant difference (P=0.0334). The difference was mainly contributed by fatigue and injection-site pain in some groups. Most adverse reactions were mild (Grade 1). We did not observe any serious adverse events related to vaccination. By day 14-28 post vaccination, the seroconversion rates and GMT of neutralizing antibody showed no significant difference between disease group and healthy group, except CAD group (P=0.03) and CRD group (P=0.04) showed slight reduction. By day 90, the neutralizing antibody GMTs were significantly reduced in each group, with no significant difference between diseases and healthy group. By day 180, the neutralizing antibody continued to decrease in each group, but with slower declination. Interpretation: For people living with chronic disease especially seniors older than 60 years, the CoronaVac vaccines are as safe as in healthy people. Although the immunogenicity is slightly different in subgroup of some diseases compared with that of the healthy population, the overall trend was consistent. Our findings highlight the evidence to address vaccine hesitancy for seniors and people living with chronic diseases. Funding: Yunnan Provincial Science and Technology Department (202102AA100051 and 202003AC100010, China), Sinovac Biotech Ltd (PRO-nCOV-4004).

Immunosuppression impaired the immunogenicity of inactivated SARS-CoV-2 vaccine in non-dialysis kidney disease patients (preprint)

Patients with chronic kidney disease (CKD) are at higher risk for coronavirus disease 2019 (COVID-19)-related morbidity and mortality. However, a significant portion of CKD patients showed hesitation toward vaccination in telephone survey of our center. Yet no serial data available on humoral response in patients with CKD, especially those on immunosuppression. We conducted a pilot, prospective study to survey the safety and humoral response to inactivated SARS-CoV-2 vaccine in CKD patients receiving a 2-dose immunization of inactivated SARS-CoV-2 vaccine. We found the neutralizing antibody titers in CKD patients was significantly lower than that in healthy controls, hypertension patients, and diabetes patients. Notably, immunosuppressive medication rather than eGFR levels or disease types showed effect on the reduction of immunogenicity. Interestingly, a third dose significantly boosted neutralizing antibody in CKD patients while immunosuppressants impeded the boosting effects. In conclusion, our data demonstrates that CKD patients, even for those on immunosuppression treatment, can benefit from a third vaccination boost by improving their humoral immunity.