You know that vaccines can work to prevent you from getting an infection (pre-exposure prophylaxis), but did you know that some vaccines work even after you have been exposed to a disease?
Post-Exposure Prophylaxis With Vaccines Works
That’s right, some vaccines work as post-exposure prophylaxis too!

It’s especially helpful for those diseases that have a long incubation period.
“People exposed to measles who cannot readily show that they have evidence of immunity against measles should be offered post-exposure prophylaxis (PEP) or be excluded from the setting (school, hospital, childcare). To potentially provide protection or modify the clinical course of disease among susceptible persons, either administer MMR vaccine within 72 hours of initial measles exposure, or immunoglobulin (IG) within six days of exposure.”
CDC on Measles for Healthcare Professionals
In addition to measles, post-exposure prophylaxis can work for hepatitis A, hepatitis B, rabies, chicken pox, and tetanus.
With hepatitis B, rabies, and tetanus, after exposure, you would typically also get a dose of immunoglobulin, in addition to a hepatitis B, rabies, or tetanus vaccines (DTaP or Tdap). With hepatitis A, immunoglobulin is typically only given if you are at high risk for a severe infection. And if you were at high risk for severe varicella, after exposure, you would get varicella-zoster immune globulin (VariZIG).
Why not just get immunoglobulin, which is basically a big shot of antibodies?
“Human rabies immune globulin (HRIG) is administered only once, at the beginning of anti-rabies prophylaxis, to previously unvaccinated persons. This will provide immediate antibodies until the body can respond to the vaccine by actively producing antibodies of its own.”
CDC on Human Rabies Immune Globulin
It’s because the passive protection that you get from the antibodies in the immunoglobulin will quickly wear off, often sooner than your body clears the virus that you were exposed to.
Getting a vaccine at the same time helps make sure that you are making your own antibodies to keep you protected when that happens.
Unfortunately, post-exposure prophylaxis with a vaccine doesn’t work for most other vaccine preventable diseases.
Want to make sure you are protected? Get vaccinated well before you are ever exposed to measles, chickenpox, hepatitis A or B, and other vaccine preventable diseases.
More on Post-Exposure Prophylaxis
- What to Do If Your Child Is Exposed to Measles
- What to Do If Your Child Is Exposed to Hepatitis B
- Can You Treat Tetanus Without a Tetanus Shot?
- 5 Myths About Tetanus and Tetanus Shots
- What to Do If Your Child Is Exposed to Hepatitis A
- What to Do If Your Child Is Exposed to Mumps
- Study – Post-Exposure Effects of Vaccines on Infectious Diseases
- CDC – Measles for Healthcare Professionals
- CDC – Human Rabies Immune Globulin
- CDC – Managing People at High Risk for Severe Varicella
- MMWR – Updated Recommendations for Use of VariZIG — United States, 2013
- WHO – Rabies vaccines and immunoglobulins: WHO position April 2018
- What is the role of tetanus immune globulin (TIG) in the treatment of tetanus (lockjaw)?
- What are the difference between HBIG and a Hepatitis B vaccine?
- Hepatitis A Postexposure Prophylaxis Guidance
- Procedures for HBsAg-Positive and Unknown Mothers and Newborns Non-Patient Specific Standing Order for the Hepatitis B Birth Dose
- Study – Use of hepatitis A vaccine for post-exposure prophylaxis in individuals over 40 years of age: A systematic review of published studies and recommendations for vaccine use.