[Medical Q&A] Is it still useful to get the measles vaccine after being in contact with a measles patient?

Planner: Chinese Medical Association

Reviewer: Huang Lei, deputy chief physician, Fifth Medical Center, PLA General Hospital

If a person who has not been vaccinated against measles or has not contracted measles comes into contact with a measles patient, emergency prevention measures can be taken such as emergency measles vaccination or immunoglobulin injection, but the specific immune effect depends on the time of contact and the timing of vaccination.

【Timing of vaccination】

(1) Vaccination within 72 hours after exposure to the measles virus: It is still possible to prevent or reduce the onset of measles. This is because the vaccine can induce the body to produce an immune response and prevent the virus from further replicating.

(2) Vaccination more than 72 hours after exposure to the measles virus: The effectiveness of the vaccine may be affected because the virus has begun to replicate in the body and the immune system may have begun to fight the virus. However, even if measles vaccination fails to control the onset of the disease, it can alleviate symptoms and reduce complications.

【Immunization method】

Immunoglobulin injection: For certain high-risk groups (such as immunocompromised people, pregnant women, etc.), immunoglobulin injection can be considered after exposure to the measles virus to provide passive immune protection. Immunoglobulin contains antibodies against the measles virus and can provide immediate protection.

【Notes】

(1) Individual differences: Each person's immune response is different. Therefore, even if you are vaccinated after exposure, there is no 100% guarantee that you will not get the disease.

(2) Monitor symptoms: Even after vaccination, contacts should be closely monitored for symptoms such as fever and rash so that they can seek medical attention promptly.

(3) Isolation measures: For individuals who have been vaccinated but are still in the observation period, appropriate isolation measures should be taken to reduce the risk of virus transmission.

【Supplementary Notes】

(1) Measles incubation period: The incubation period of measles is generally 7 to 14 days, and the time window for vaccination after exposure is limited.

(2) Vaccination recommendations: If you have missed the best time for vaccination, it is still recommended to complete the vaccination according to the regular vaccination procedures to establish long-term immune protection.