Nutritional Advice El Mondo
Objectives:
The objectives of this review article is to evaluate the effect of age at administration of the first dose of a measles-containing vaccine (MCV1) on protection against measles and on antibody response after one- and two-dose measles vaccinations.
Study design:
This review article included 41 (29 retrospective cohort studies and 12 case-control studies. Although 29 studies were conducted in large epidemics (≥100 cases), only 11 (27%) reported > 100 cases with data on vaccination status and age and 2 (5%) presented less than 10 cases) in the measles protection and 67 trials (8 RCTs, 25 non-RCTs and 34 before-after studies. Sample size varied from 21 to 1,633 participants and 72% include > 100 vaccinated children) in the immunogenicity analyses.
Funnel plots did not show much asymmetry but most of the effect estimates were plotted close to the pooled measure, suggesting that publication bias might exist but did not have a major impact on the results.
Results and conclusions:
The investigators found older age at MCV1, from 6 to ≥15 months, significantly improved antibody response and measles protection among one-dose recipients.
The investigators found pooled measles RR ranged from 3.56 [95% CI = 1.28 to 9.88] for MCV1 at 9 months to 0.48 [95% CI = 0.36 to 0.63] for MCV1 at ≥15 months, both compared to 12-14 months.
The investigators found pooled seroconversion RR ranged from 0.93 [95% CI = 0.90 to 0.96] for MCV1 at 9-11 months to 1.03 [95% CI = 1.00 to 1.06] for MCV1 at ≥15 months, both compared to 12 months.
The investigators found after a second dose, serological studies reported high seropositivity regardless of age at administration of MCV1 while epidemiological data based on few studies suggested lower protection with earlier age at MCV1.
The investigators concluded in children born to mothers who had measles, an earlier age at MCV1 decreases measles protection and immunogenicity after one dose and might also decrease protection after two doses of measles vaccine. While two-dose vaccination coverage is most critical to interrupt measles transmission, older age at first vaccination may be necessary to keep the high level of population immunity needed to maintain it.
Original title:
Effect of age at vaccination on the measles vaccine effectiveness and immunogenicity: systematic review and meta-analysis by Carazo S, Billard MN, […], Serres G.
Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7104533/
Additional information of El Mondo:
Find more information/studies on vaccination, food fortification and measles right here.