A rubella titer result is less than 1:8 at an initial prenatal visit. Which statement best describes what this means?

• A. The titer result is not interpretable during pregnancy.
• B. You are susceptible to rubella infection.
• C. The titer result means you had a rubella infection in the past.
• D. You have immunity to rubella.

Answer: (B)

Rubella immunity is determined by antibody levels. A titer below the protective threshold means there are no circulating protective antibodies to rubella, so you are not immune. In pregnancy, being non-immune makes you susceptible to rubella if you’re exposed, and rubella infection during pregnancy can risk the fetus. This result does not indicate a past infection (that would show immunity) and it does not indicate an active infection. Therefore, the statement that best describes this result is that you are susceptible to rubella infection. After delivery, vaccination is recommended to protect future pregnancies, since the rubella vaccine is not given during pregnancy.