After a child has had the chickenpox vaccine, he or she may still develop chickenpox under more specific circumstances. Chickenpox is an acute, viral, rash disease. The typical manifestation of chicken pox without vaccination is that the onset of the disease is more acute and can have fever, lethargy, nausea, vomiting, headache, sore throat and other discomforts. The chickenpox vaccine can be effective in preventing chickenpox or reducing the symptoms of chickenpox. Having had the chickenpox vaccine generally prevents the occurrence of chickenpox, but the effectiveness of the vaccination and the differences in the quality of the vaccine and the vaccination may lead to differences in the effectiveness of the vaccination, so chickenpox may still occur. However, in a vaccinated patient, his symptoms are less typical, the temperature is not elevated or only mildly elevated, the rash pattern is atypical or the rash is less frequent, and the symptoms are significantly reduced and accompanied by fewer symptoms. The rash is still contagious, so it should still be isolated, have a light diet, drink plenty of water, avoid getting cold, etc. If the symptoms are serious, you should seek medical attention in time.