- subjects were previously confirmed cases of covid-19 or asymptomatic infected persons. - being allergic to any component of vaccines (including excipients) . - subjects who have experienced severe allergic reactions to vaccines (e.g. acute anaphylaxis, urticaria, angoneeurotic edema, dyspnea, etc.). - having uncontrolled epilepsy and other progressive neurological disorders and a history of guillain-barre syndrome. - injection of non-specific immunoglobulin within 1 month before enrollment. - pregnant and lactating women. - the subjects are suffering from an acute illness; or thrombocytopenia patients with platelet count < 20×10^9/l within three days before inoculation, that is, patients at high risk of spontaneous bleeding. - acute hiv infection and opportunistic infection. - subjects with co-opportunistic infections who did not receive antiviral therapy. - subjects with cd4+ count less than 50/ul who have not received antiviral therapy. - hiv-infected subjects undergoing treatment with severe drug interactions and overlapping toxicity (kidney damage, liver damage, hematological problems, etc.). - patients with malignant tumors are undergoing chemotherapy and radiotherapy before and after surgery. - subjects who had vaccine-related adverse reactions after the second dose. - having high fever (axillary temperature ≥39.0℃) for three days after the second dose of inoculation, or severe allergic reaction. - having any adverse nervous system reaction after the second dose. - other subjects whose physical conditions, as determined by the investigator, are not suitable for inclusion in clinical studies.

- subjects were previously confirmed cases of covid-19 or asymptomatic infected persons. - being allergic to any component of vaccines (including excipients) . - subjects who have experienced severe allergic reactions to vaccines (e.g. acute anaphylaxis, urticaria, angoneeurotic edema, dyspnea, etc.). - having uncontrolled epilepsy and other progressive neurological disorders and a history of guillain-barre syndrome. - injection of non-specific immunoglobulin within 1 month before enrollment. - pregnant and lactating women. - the subjects are suffering from an acute illness; or thrombocytopenia patients with platelet count < 20×10^9/l within three days before inoculation, that is, patients at high risk of spontaneous bleeding. - acute hiv infection and opportunistic infection. - subjects with co-opportunistic infections who did not receive antiviral therapy. - subjects with cd4+ count less than 50/ul who have not received antiviral therapy. - hiv-infected subjects undergoing treatment with severe drug interactions and overlapping toxicity (kidney damage, liver damage, hematological problems, etc.). - patients with malignant tumors are undergoing chemotherapy and radiotherapy before and after surgery. - subjects who had vaccine-related adverse reactions after the second dose. - having high fever (axillary temperature ≥39.0℃) for three days after the second dose of inoculation, or severe allergic reaction. - having any adverse nervous system reaction after the second dose. - other subjects whose physical conditions, as determined by the investigator, are not suitable for inclusion in clinical studies.