Three year olds are usually able to get the new crown vaccine. At present, children and adolescents aged 3 to 17 years are able to receive the New Crown vaccine. At present, the vaccine approved for use in children in China is the inactivated New Crown virus vaccine, with 2 doses, the interval between the 2 doses is recommended to be ≥3 weeks, and the second dose should be completed within 8 weeks after the completion of the first dose, and the dosage and method of use are the same as those for adults. Some children may have adverse reactions, such as mild diarrhea, fever, rash, etc. Most of them can subside on their own in 1~2 days. Do not allow children to scratch the injection site, drink plenty of water, eat a light diet and avoid spicy food. It should be noted that if the child has a previous allergy to vaccination, or suffers from severe neurological disease, or is in the acute stage of illness, it is not recommended to take the new crown vaccine. Since 3-year-olds may have adverse reactions to the vaccine, it is recommended that they be vaccinated under professional supervision.