Nutritional Advice El Mondo
Objectives:
Vaccinating infants with a first dose of measles-containing vaccine (MCV1) before 9 months of age in high-risk settings has the potential to reduce measles-related morbidity and mortality. However, there is concern that early vaccination might blunt the immune response to subsequent measles vaccine doses. Therefore, this review article (meta-analysis) has been conducted.
Does measles-containing vaccine (MCV1) administration to infants younger than 9 months reduce immune responses to subsequent MCV doses?
Study design:
This review article included 13 studies.
Overall, the quality of evidence was moderate to very low.
Results and conclusions:
The investigators found from 13 studies, the pooled proportion of infants seropositive after two measles-containing vaccine doses, with MCV1 administered before 9 months of age, was 98% [95% CI = 96-99, I2 = 79.8%, p 0.0001], which was not significantly different from seropositivity after a two-dose MCV schedule starting later [p = 0.087].
The investigators found only 1 of 4 studies found geometric mean titres after MCV2 administration to be significantly lower when MCV1 was administered before 9 months of age than at 9 months of age or later.
The investigators found there was insufficient evidence to determine an effect of age at MCV1 administration on antibody avidity.
The investigators found the pooled vaccine effectiveness estimate derived from 2 studies of a two-dose MCV schedule with MCV1 vaccination before 9 months of age was 95% [95% CI = 89-100, I2 = 12.6%, p = 0.29].
The investigators found 7 studies reporting on measles virus-specific cellular immune responses found that T-cell responses and T-cell memory were sustained, irrespective of the age of MCV1 administration.
The investigators concluded administering MCV1 to infants younger than 9 months followed by additional MCV doses results in high seropositivity, vaccine effectiveness and T-cell responses, which are independent of the age at MCV1, supporting the vaccination of very young infants in high-risk settings. However, there is some evidence that MCV1 administered to infants younger than 9 months results in lower antibody titres after one or two subsequent doses of MCV than when measles vaccination is started at age 9 months or older. Therefore, the clinical and public-health relevance of this immunity blunting effect are uncertain.
Original title:
Effect of measles vaccination in infants younger than 9 months on the immune response to subsequent measles vaccine doses: a systematic review and meta-analysis by Nic Lochlainn LM, de Gier B, [...], Hahné SJM.
Link:
https://www.ncbi.nlm.nih.gov/pubmed/31548081
Additional information of El Mondo:
Find more information/studies on vaccination and food fortification/malnutrition right here.