A runny nose after an inactivated influenza vaccine could be a cold; a runny nose after an attenuated live influenza vaccine could also be an adverse reaction to the vaccine. The inactivated influenza vaccine is a dead vaccine and does not cause influenza after vaccination, so there are usually no symptoms such as a runny nose. A runny nose after receiving the inactivated influenza vaccine may be caused by a cold and a runny nose due to a decrease in the body’s immunity. Take care to rest after the flu shot and increase your clothing in time to prevent catching a cold. Children with a runny nose after receiving the live attenuated influenza vaccine (nasal spray influenza vaccine) may also have an adverse reaction to the vaccine. Common adverse reactions to live attenuated influenza vaccine are runny or stuffy nose, headache, fever, myalgia, etc., which usually get better on their own in 2~3 days and do not require special treatment.