Objective: To establish the most appropriate age ranges for the use of human normal immunoglobulin and MMR vaccine as post exposure prophylaxis.
Design: Review of literature and of laboratory confirmed measles cases.
Setting: England and Wales and countries with a similar measles epidemiological profile.
Patients: Women of childbearing age and infants.
Main outcome measures: The risk of measles, maternally derived measles antibody levels and the response to measles containing vaccines in infants.
Results: By 4 to 5 months of age, only 28-45% of infants born to women from highly vaccinated populations have protective levels of measles antibody. In the post-vaccine era, between 74% and 80% of infants vaccinated between 6 and 9 months respond to vaccine and around 67% have clinical protection from measles vaccination.
Conclusion: Our review suggests that many infants being born in the UK will become susceptible to measles before six months and will be able to respond to vaccine between 6 and 9 months of age. We propose that current guidance is changed to recommend passive immunisation with human normal immunoglobulin for most infants exposed to measles below six months of age. For infants aged six months or over exposed to measles, vaccination with MMR may be given.