There are various types of New Crown vaccines, each with different doses, and whether or not three doses must be completed depends on the type of vaccine, in the following cases: 1. Three doses must be completed: If the patient is vaccinated with recombinant CHO cell vaccine, three doses must be completed, and it is also recommended that there be at least a four-week interval between each vaccination. If the vaccination is not given on time, the patient should go to the hospital in time for a catch-up vaccination to avoid vaccination failure caused by incomplete vaccination; 2. No need for three doses: The new crown vaccine type also has adenovirus vector vaccine, which requires only one dose, and in this case, three doses are not necessary; 3. Other cases: Inactivated vaccine currently requires two doses, but many regions have started to inject the third booster, so whether three doses must be completed is recommended The decision will be made according to the requirements of the local health department. In addition, after receiving the new crown vaccine, you should stay at the vaccination site for 30 minutes to observe in case of adverse reactions to the vaccine, such as redness and swelling of the skin at the vaccination site, local reactions such as itching, hard nodules and pain, and in severe cases, nausea, vomiting, general weakness and allergy. If the above discomfort occurs at the site, you should promptly explain the situation to the medical staff and actively cooperate with the treatment, and if the above discomfort occurs after returning home, you should promptly seek medical consultation. Pay attention to keeping the skin at the wound clean and dry, and avoid bathing within 24 hours of vaccination. Eat a light diet, eat more fresh fruits and vegetables, eat less spicy and stimulating food, and reduce strenuous activities and staying up late to avoid aggravating physical weakness and other conditions.