Is an Additional Measles Vaccine Dose Beneficial?

An additional, early dose of the measles vaccine (MV) may be associated with increased protective levels of measles antibodies, but likely does not reduce mortality among children aged 4 to 7 months, according to a new study.

For their study, the researchers assessed 8309 children aged 4 to 7 months from Burkina Faso and Guinea-Bissau from July 18, 2012, to December 3, 2015.
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Each child was randomly assigned to receive either an extra early standard dose of MV (Edmonston-Zagreb strain) or no extra MV at 4 weeks following the third diphtheria-tetanus-pertussis-hepatitis B-Haemophilus influenzae type b vaccine. Subsequently, at 9 months, all children were administered a routine MV.

Mortality, which was evaluated via home visits, was compared from enrollment to age 3 years using Cox proportional hazards models.

In addition, blood samples were obtained from subgroups of children to assess measles antibody levels.

Ultimately, 145 children died, translating to a mortality rate of 16 per 1000 person-years. Results indicated that the mortality rate was lower than expected and did not differ between groups (hazard ratio 1.05).

At enrollment, protective measles antibody levels were evident in 16 (4%) children in Burkina Faso and 90 (21%) in Guinea-Bissau. At 9 months, no measles-unvaccinated and measles-unexposed children demonstrated protective antibody levels, whereas 306 (92%) of children who received early MV had protective levels.

At final follow-up, protective antibody levels were present in 186 (98%) of children in the early MV group in 196 (97%) of children in the control group.

“Early MV did not reduce all-cause mortality,” the researchers concluded. “Most children were susceptible to measles infection at age [4 to 7] months and responded with high antibody levels to early MV.”

—Christina Vogt

Reference:

Fisker AB, Nebie E, Schoeps A, et al. A two-center randomized trial of an additional early dose of measles vaccine: Effects on mortality and measles antibody levels. Clin Infect Dis. 2018;66(10):1573-1580. https://doi.org/10.1093/cid/cix1033