People who are not allowed to receive the third vaccination include people with acute exacerbation of chronic diseases, mental diseases, pregnant women, people with history of severe allergy, and people who have not received the first two vaccinations. 1. People with acute exacerbations of chronic diseases, such as chronic bronchitis and hypertensive crisis, are not eligible for vaccination. 2. People with poorly controlled mental illnesses, such as epilepsy, vaccination may cause seizures. 3. Pregnancy, women in pregnancy should not be vaccinated to avoid any effect on the fetus. 4. History of severe allergy, such as shock, respiratory failure and other conditions of severe allergic people. 5. People who have not received the first two injections should not receive the third injection directly, and need to complete the first two injections first. The new crown vaccine should be inoculated in regular medical or disease control institutions.