Common side effects from the inactivated influenza vaccine include soreness, redness and swelling where the vaccine was given. Other symptoms, that may last 1 to 2 days, can include fever, headache, muscle soreness, fatigue, nausea, vomiting, diarrhea and chills. Babies and young children may be irritable, sleepy and have a decreased appetite. Fewer than 1 in 20 people may have oculo-respiratory syndrome (ORS). Symptoms of ORS include red eyes, a cough and/or sore throat and/or hoarseness.
The live attenuated influenza vaccine contains weakened influenza viruses and may cause mild influenza symptoms but these are much milder than those due to influenza infection. Symptoms may include a runny or stuffy nose, cough, sore throat and fever. Other symptoms can include headache, decreased appetite, weakness, muscle soreness, chills, vomiting, stomach ache and irritability.