Given that I had all of my childhood vaccines (or the actual illness), I assumed I had measles immunity. But recently, much to my surprise, I found out that I did not. There has been a measles outbreak in South Carolina, and the SC Department of Health has reported nearly 1000 cases as of March 20, 2026. While there have been additional outbreaks in the US, e.g. in Texas, the one in SC has led to some spillover in my home state of North Carolina.
As a result measles immunity has been in the news a lot lately. This news includes (sometimes confusing) information on whether or not previously vaccinated people are in fact immune. This information is based on year of birth, year(s) of vaccination, and type of vaccination. Since measles is highly contagious and can cause serious complications I wondered if I needed to be concerned about my measles immunity status.
Brief history of the measles vaccine and effectiveness
The measles vaccine first became available in 1963. There were two versions. One was an inactivated version that was later found to be ineffective. It was discontinued in 1967. The other was a live attenuated version made from a weakened version of the virus. This live vaccine was found to be effective. A new version of the live vaccine became available in 1968 and this is the version that is still used. In 1971 it was combined with the mumps and rubella vaccines — this is known as the MMR vaccine. From 1968 until 1989 most people received only one dose of the vaccine. In 1989 the guidance changed and two doses became the norm. One dose is about 93% effective while two doses increases effectiveness to 97%.
A nice summary of the history of the measles vaccine is in this Forbes article. A more detailed history of the development of the measles vaccine is in this article from the WHO. Other summaries of the history of the vaccine and recommendations for getting another vaccine include these articles from Harvard and the Cleveland Clinic.
I summarized the findings in the table below. While recommendations for those born before 1957 and after 1989 are clear, I still find some confusion, and a lack of clarity for those born between 1957 and 1989.
A summary of guidance based on year of birth
| Year born | Need measles vaccine? | Comments |
| Before 1957 | No | Considered immune due to measles exposure |
| 1957-1976 | Maybe | If vaccinated with the inactivated vaccine or not sure which vaccine may need one. Or if only received one dose of the live vaccine. Vaccines during this time had varying levels of effectiveness according to Mayo Clinic experts. |
| 1976-1989 | Maybe | If only received one dose of the live vaccine may need one. Different things I read have differing opinions as to whether one dose is sufficient though many recommend certain groups get a second dose. |
| After 1989 | No | Should have received two doses of the live vaccine which is the current recommendation |
What I did
First I looked at my vaccination records and found I received measles vaccines in 1963 and 1973. But I had no information as to the type(s) of vaccine that I received. I was debating if I should just go get a new vaccine when I saw a friend’s post about measles immunity on Facebook. Someone commented on the post that she had had blood drawn to check for antibodies to measles (known as titers) and found that she was not immune.
At this point I decided to contact my doctor. He said I could just go ahead and get an MMR vaccine since there is no harm in doing this. I asked if I could have titers done. He put in the order and a few days later I had my blood drawn. The next morning I received the results– no immunity to measles. By afternoon I was in CVS getting an MMR vaccine.
I must say even though I wanted clarity on my measles immunity I was still surprised. Given that I received one vaccine in 1973, I assume that was the live virus. And one dose is considered 93% effective. So sure I could be in the 7%. But it does make me wonder about the effectiveness for those vaccinated in the early 70s.
What should you do
The information in this post is a summary of sources I read along with my own experiences. For anyone wondering about their own measles immunity and whether or not to get vaccinated it is a good idea to consult a medical professional.
Back to Health & Wellness
