human
I've heard that the flu vaccine is not effective for children under 6 years old, is that true?
assistant
It depends on what you mean by “effective.” The flu vaccine can reduce your risk of getting the flu, but it does not guarantee that you will not get sick. In fact, there are many different types of flu viruses and they are constantly changing, so even if you get vaccinated against a particular strain of flu virus, it is possible that you could still get infected with another type of flu virus.