An HIV-Positive Child Has Low Titers After a Measles Vaccination

An HIV-positive child has low titers after a measles vaccination.She has now been exposed to the disease.Which action by the nurse is most appropriate?

A) Administer prophylactic antibiotics.
B) Place the child in protective isolation.
C) Prepare to administer immunoglobulin.
D) Repeat the vaccination as soon as possible.