SAFETY AND IMMUNOGENICITY OF EARLY MEASLES VACCINATION IN CHILDREN BORN TO HIV-INFECTED MOTHERS IN THE UNITED STATES: RESULTS OF PEDIATRIC AIDS CLINICAL TRIAL GROUP (PACT) PROTOCOL 225

Tuesday, 28th of January 2014

[source]Journal of Infectious Diseases[|source]

When considering protection of HIV-infected infants against measles one has to think of: a)optimal immunization age, b) the safety profile of measles vaccine among infants below 12 months of age, and c) a vaccination schedule providing longest-term protection. Studies of HIV infected 6–12-month-old vaccinees have suggest a trend toward higher seroresponse rates and higher postvaccination measles antibody seroprevalence compared to those receiving 1 primary dose >12 months.

In this report, the authors tested the hypothesis that HIV-infected children vaccinated at 6 months in the United States would develop a higher and more durable response to measles vaccine than HIV-infected children vaccinated after 12 months due to relative intactness of the immune system of the HIV-infected child in early life. Among others, this study confirms that measles vaccination in HIV-infected children is more tolerated at 6 months. The study therefore is supportive of the WHO recommendation to administer a first dose of measles vaccine at 6 months of age to HIV-infected children. More details are available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3143449/

 

Abstract

Background: PACTG (Pediatric AIDS Clinical Trials Group) 225, a multicenter, randomized, open-label trial in the United States evaluated reactogenicity and immunogenicity of 2 vaccination regimens: monovalent measles vaccine (Attenuvax) at 6 months of age and measles, mumps, and rubella, live attenuated (MMRII) vaccine at 12 months of age (2D), or only MMRII at 12 months of age (1D) in human immunodeficiency virus–infected (HIV-infected) (POS) and uninfected (NEG) children in the pre–highly active antiretroviral therapy (pre-HAART) period.

Methods: Plaque-reduction neutralization (PRN) of measles-neutralizing antibody titers were evaluated at study weeks 0, 6, 26, 32, 52, and 130 (∼3 years of age).

Results: The 110 subjects included: 65 2DNEG; 30 1DNEG; 7 2DPOS and 8 1DPOS. Vaccinations (n = 175) were associated with no adverse experiences >Grade 2 except for Grade 3 fever (n = 2, 1 1DPOSand 1 1DNEG). Six weeks after Attenuvax, all 2DPOS subjects (7/7) seroresponded (PRN titers ≥120 mIU/mL) with median titers significantly exceeding 2DNEG titers (2115 vs 628 mIU/mL, respectively;P = .023). At ∼3 years of age, 67% 1DPOS (4/6) and 83% 2DPOS (4/5) subjects maintained titers ≥120 mIU/mL. Prevaccination titers ≥25 mIU/mL among 2DNEG subjects correlated inversely with the likelihood of achieving titers ≥120 mIU/mL (56% vs 90%; P = .004).

Conclusions: Among HIV-infected children pre-HAART, Attenuvax at 6 months was well tolerated and immunogenic. These data support the current World Health Organization (WHO) recommendation to administer a first dose of measles vaccine at 6 months of age to HIV-infected children.