After giving informed consent, patients with hypertension, patients with diabetes, patients with both diseases, and healthy controls, all aged 60 years or older, are given a third doses of the inactivated SARS-CoV-2 vaccine (Vero cells).
These subjects are all from the "COVAX (HT/DM)-Wuhan" clinical trial (NCT05065892). 50% of them receive the booster vaccine 3 months after the second dose (0-1-4 schedule); 50% of them receive the booster vaccine 5 months after the second dose (0-1-6 schedule).
Venous blood samples are collected before the booster dose and on day 28 after the booster dose to evaluate the immunogenicity of the vaccine.
Venous blood samples are also collected on day 84/168/252/336 after the booster dose to evaluate the antibody persistence of the vaccine.
Adverse events are actively recorded on a diary card once daily from day 0 to day 7 and once from day 8 to day 21 after the booster dose. Serious adverse events (SAE) are collected within 6 months after the booster dose.
