Vaccines are safe and essential for public health, and most side effects are mild and short-lived. Pain, redness or swelling at the injection site, fever, fatigue, headache and body aches usually go away on their own. Medical advice is needed if symptoms are extreme, long-lasting, worsening or unusual, such as a high or persistent fever, extreme swelling, extreme tiredness, prolonged vomiting, or increasing redness, warmth and pain at the injection site. Signs of a serious allergic reaction need immediate attention, including breathing difficulty, swelling of the face, lips or neck, widespread rashes, sudden dizziness or fainting and low blood pressure. Symptoms like seizures, severe headache or unusual bleeding should be evaluated urgently rather than automatically blamed on the vaccine. Parents should watch children closely for excessive sleepiness, persistent crying or difficulty breathing. Do not skip later vaccine doses without first consulting your doctor.
