Two doses of the MMR vaccines give the great majority of people long lasting immunity to measles, mumps, and rubella. Well, measles and rubella anyway. Unfortunately, the mumps part of the vaccine has some issues with waning immunity.
Do you need to get your titers checked to make sure you are immune?
Usually not. Simply being fully vaccinated with the MMR vaccine is good enough evidence that you are immune in most, but not all circumstances
Getting or being pregnant is one of those circumstances in which it is important to know for sure. It is really one of the only circumstances. Health care works are no longer routinely tested after they are vaccinated, as proof of vaccination is good evidence of immunity for the MMR vaccine.
That screening test is a rubella serum IgG levels or as it is more commonly known as, a titer level.
Non-Immune Rubella Titers
Why check it?
Because of the devastating effects of congenital rubella syndrome, all pregnant women are screened early in their pregnancy.
Having a positive rubella titer, typically defined as a IgG level of ≥10 IU/mL, means that you are immune and protected.
But what if your rubella titer is negative? What if your level is <10 IU/mL?
We know that levels of vaccine-induced rubella antibodies can decrease over time, but unlike mumps and pertussis, this does not seem lead to waning immunity with rubella.
Still, the current recommendations from the Advisory Committee on Immunization Practices (ACIP) are that:
- Vaccinated women of childbearing age who have received one or two doses of rubella-containing vaccine and have a rubella serum IgG levels that is not clearly positive should be administered one additional dose of MMR vaccine, with a maximum of three doses.
- After this additional dose, they do not need to be retested for serologic evidence of rubella immunity.
- Since MMR is a live vaccine, the additional dose should not be given during pregnancy or within a month of when you plan to get pregnant. You can get it while you are breastfeeding though.
How much should you be concerned about a negative rubella titer?
Although congenital rubella syndrome is not uncommon in other countries that don’t routinely vaccinate for rubella, there has not been a case of congenital rubella syndrome in the United States since – 2017.
That’s right, we have actually had two cases of congenital rubella syndrome in the US this year! In past years, these cases have all been linked to pregnant women becoming infected outside the US though, as there are thought to be very few rubella infections locally.
And two cases is a far cry from when rubella caused 2,100 neonatal deaths and 20,000 infants to be born with congenital rubella syndrome during an epidemic in the mid-1960s, before the first rubella vaccine was available.
That’s because vaccines work.
Wait, then why do some of these folks have a negative titer when they are tested?
While the easy answer is to say that they aren’t immune, it is more complicated than that. For example, some of the negative results could be false negatives (a negative test result that really should be positive). Others could possibly have low antibody levels, but they are still immune. Still, since one dose of a rubella containing vaccine is only about 97% effective, some of them could be non-responders.
Will a second or third booster dose of vaccine help increase your antibody levels? Yes, but in this situation, they will likely just rise temporarily. The second or third dose of MMR isn’t technically a booster dose, but rather a dose for those who didn’t respond to the previous doses, particularly for the measles component.
With a negative rubella titer, especially if you have not been previously vaccinated with one or more rubella-containing vaccines, you should likely try to avoid anyone who might have rubella.
There aren’t a lot of guidelines on how to avoid rubella though.
That probably surprises you, especially with all of the information out there on how to avoid the flu, measles, mumps, and other infectious diseases, but it shouldn’t.
Symptoms of a rubella infection can include swollen lymph glands, low grade fever, a mild case of pink eye, and a red rash that can be hard to see, unless the person is overheated, like after a bath. Most importantly, people with rubella can be contagious for another few weeks, even as all of the symptoms have gone away. Also, like most viral infections, they were contagious for a few days even before they developed their first symptoms. And, believe it or not, some people with rubella might have no symptoms at all and still be contagious.
So how do you avoid someone who doesn’t even know that they are sick and are still contagious?
You basically want to try and away from anyone who might become sick and contagious…
While that sounds impossible, avoiding kids and adults who are intentionally unvaccinated, especially those who are intentionally unvaccinated and have recently traveled out of the country, can be a good start.
And like someone with a medical exemptions to getting vaccinated, if you have been vaccinated and lost your immunity to rubella, feel free to hide in the herd. This is one of the reasons everyone gets vaccinated!
What to Know About Rubella Titers
Get vaccinated and follow the latest guidelines if you are pregnant and your rubella titer is negative.
More on Rubella Titers and Immunity
- ACOG – Routine Tests During Pregnancy
- MMWR – Prevention of Measles, Rubella, Congenital Rubella Syndrome, and Mumps, 2013 (ACIP Summary)
- Study – Evaluation of Eight Anti-Rubella Virus Immunoglobulin G Immunoassays That Report Results in International Units per Milliliter
- Ask the Experts About MMR
- Rubella: Questions and Answers
- CDC – Rubella in the US
- MMWR – Three Cases of Congenital Rubella Syndrome in the Postelimination Era
- Rubella and pregnancy
- Study – Rubella immunity. Defining the level of protective antibody.
- Study – How to determine protective immunity in the post-vaccine era.