Understanding Your Immunity: The Importance of Measles Titers

Measles is Back!

I never imagined I would have to address this topic, but given recent developments, it's essential. It’s 2025, and if you’ve been following the news, you may have heard about the recent measles outbreaks across the country, particularly in Texas and here in Kansas. Most reported cases are in the southwestern counties of Kansas, but the true number likely exceeds the 37 officially reported cases. This is surprising, especially since during my medical training, I was informed that I would probably never encounter measles firsthand.

With this outbreak, many patients are understandably concerned about their immunity and whether they should receive a vaccination or booster shot. Let’s explore the nuances of this topic, which depend on your birth year, risk factors, and personal health history.

Titers: The Easy Approach

If you want clear advice on understanding your immunity status, I recommend that adults check their blood work for titer levels. Specifically, measuring IgG (immunoglobulin G) levels for measles can show your immune system's long-term memory, indicating protection from previous vaccinations or infections. High IgG levels suggest that you have immunity.

In medical training, whether for doctors or nurses, checking titer levels is standard practice before working in clinical settings, as it provides reliable assurance of immunity. Simply having records of childhood vaccinations, such as the MMR (measles, mumps, and rubella) vaccine, is not enough for reassurance.

The titer test is straightforward and only requires a blood draw. In our practice, it costs about $10. Whether you have been vaccinated or not, checking your blood levels can confirm if you are immune.

What if You're Already Vaccinated?

If you have received the vaccine and possess documentation of two doses, most guidelines indicate that you are likely immune. While nothing in biology or medicine is absolutely perfect, the standard MMR vaccine is approximately 97% effective, even in the event of exposure. For the remaining 3% who may not be protected, the only way to confirm immunity is through titer testing. In the first ten years following the introduction of the measles vaccine, vaccine failures were more common. Individuals born between 1957 and 1968 should consider checking their titer levels.

Considering Booster Doses

For those unsure of their vaccination status, some guidelines recommend considering a booster dose, especially if born between 1957 and 1968. It’s generally safe, but again, checking titers provides clarity on whether it’s necessary.

For Those Not Vaccinated

If you weren't vaccinated, particularly if born after 1957 in the United States, it's likely you are not immune due to low rates of natural infection. I recommend presuming a lack of immunity unless proven otherwise.

What If I Had It As a Kid?

For those over 70, the likelihood is high that you had measles before vaccines were available, but checking titer levels is always an option for reassurance.

What if You’re Not Immune? (negative titers)

If you don't have adequate titer levels and aren't immune to measles, the next step is to start the MMR vaccine series, two doses spread over a few months to achieve approximately 97% protection. This is a community concern, not just a personal one. If you’re uncertain about your immunity status, speak with your doctor. If you’re in our practice, give us a call. We'll help you determine the next steps to ensure you and your loved ones are protected. Stay informed and stay protected.

Sincerely,
Dr. Neu