TY - JOUR

T1 - Immunogenicity and reactogenicity following MMR vaccination in 5–7-month-old infants

T2 - a double-blind placebo-controlled randomized clinical trial in 6540 Danish infants

AU - Vittrup, Dorthe Maria

AU - Jensen, Andreas

AU - Sørensen, Jesper Kiehn

AU - Zimakoff, Anne Cathrine

AU - Malon, Michelle

AU - Charabi, Salma

AU - Johansen, Marie Ryberg

AU - Simões, Eric A.F.

AU - Kirkby, Nikolai Søren

AU - Buus, Søren

AU - Svensson, Jannet

AU - Stensballe, Lone Graff

N1 - Publisher Copyright: © 2024 The Authors

PY - 2024

Y1 - 2024

N2 - Background: Measles is a highly contagious viral disease. Vaccinated mothers transfer fewer antibodies during pregnancy, resulting in shortened infant immunity. Earlier primary vaccination might avert the gap in protection. Methods: Healthy 5–7-month-old Danish infants were assigned in a 1:1 ratio to M-M-RVaxPro or placebo (solvent) in a double-blind, randomized trial between April 15, 2019 and November 1, 2021 (ClinicalTrials.gov NCT03780179, EudraCT 2016-001901-18). Eligibility criteria were birth weight >1000 g and gestational age ≥32 weeks. Immunogenicity was measured by plaque reduction neutralization test (PRNT) and IgG ELISA before intervention, four weeks after intervention and routine MMR. Reactogenicity data were collected for six weeks and measured by hazard ratios (HR). Findings: 647 and 6540 infants participated in the immunogenicity and reactogenicity study, respectively; 87% and 99% completed follow-up. After early MMR, seroprotection rates (SPRs) were 47% (13%) in measles PRNT; 28% (2%), 57% (8%) in mumps and rubella IgG (placebo). For measles PRNT, geometric mean ratio was 4.3 (95% CI: 3.4–5.3) between randomization groups after intervention and 1.5 (95% CI: 1.3–1.9) after routine MMR. Reactogenicity was independent of randomization (HR, 1.0; 95% CI: 0.9–1.1). Severe adverse events occurred in 25 infants (HR, 1.8; 95% CI: 0.8–4.0); none deemed vaccine related. Interpretation: Early MMR elicited low SPRs but did not negatively impact short-term responses to a subsequent MMR. MMR at 5–7 months was safe and not associated with higher rates of reactogenicity than placebo. Funding: Innovation Fund Denmark.

AB - Background: Measles is a highly contagious viral disease. Vaccinated mothers transfer fewer antibodies during pregnancy, resulting in shortened infant immunity. Earlier primary vaccination might avert the gap in protection. Methods: Healthy 5–7-month-old Danish infants were assigned in a 1:1 ratio to M-M-RVaxPro or placebo (solvent) in a double-blind, randomized trial between April 15, 2019 and November 1, 2021 (ClinicalTrials.gov NCT03780179, EudraCT 2016-001901-18). Eligibility criteria were birth weight >1000 g and gestational age ≥32 weeks. Immunogenicity was measured by plaque reduction neutralization test (PRNT) and IgG ELISA before intervention, four weeks after intervention and routine MMR. Reactogenicity data were collected for six weeks and measured by hazard ratios (HR). Findings: 647 and 6540 infants participated in the immunogenicity and reactogenicity study, respectively; 87% and 99% completed follow-up. After early MMR, seroprotection rates (SPRs) were 47% (13%) in measles PRNT; 28% (2%), 57% (8%) in mumps and rubella IgG (placebo). For measles PRNT, geometric mean ratio was 4.3 (95% CI: 3.4–5.3) between randomization groups after intervention and 1.5 (95% CI: 1.3–1.9) after routine MMR. Reactogenicity was independent of randomization (HR, 1.0; 95% CI: 0.9–1.1). Severe adverse events occurred in 25 infants (HR, 1.8; 95% CI: 0.8–4.0); none deemed vaccine related. Interpretation: Early MMR elicited low SPRs but did not negatively impact short-term responses to a subsequent MMR. MMR at 5–7 months was safe and not associated with higher rates of reactogenicity than placebo. Funding: Innovation Fund Denmark.

KW - Early immunization

KW - Immunogenicity

KW - Measles vaccination

KW - MMR

KW - Reactogenicity

U2 - 10.1016/j.eclinm.2023.102421

DO - 10.1016/j.eclinm.2023.102421

M3 - Journal article

C2 - 38292039

AN - SCOPUS:85182576412

VL - 68

JO - EClinicalMedicine

JF - EClinicalMedicine

SN - 2589-5370

M1 - 102421

ER -