In general, vaccines do not fail when you drink ice water. Vaccines are produced by the body’s immune system in response to specific antigens in the vaccine, producing specific antibodies that clear the specific antigens in the vaccine and make the body immune to the specific virus. Drinking ice water will not affect the immune response in the body, so the vaccine will not be ineffective. Although drinking ice water will not affect the effectiveness of the vaccine, it is still not recommended to drink ice water after vaccination. This is because the body may have certain adverse reactions after vaccination, such as nausea, vomiting, diarrhea, etc. Drinking ice water after vaccination is more likely to cause these adverse reactions, and in serious cases, it may also lead to gastrointestinal diseases such as acute gastroenteritis. If you drink ice water after vaccination and experience nausea, vomiting, diarrhea, or other adverse reactions such as dizziness or headache, you should not take medication on your own. You can first take proper rest and keep warm to see if the symptoms are relieved. If the symptoms persist or are more serious, you should go to the hospital promptly for treatment under the guidance of a doctor. After vaccination, attention should be paid to adequate rest, no heavy physical work should be performed, and a light diet with no spicy and stimulating foods or drinks is recommended to help the organism complete the specific immune response. After vaccination, it is recommended to drink room temperature water to protect the stomach and reduce the risk of diarrhea.