The effect of early measles vaccination on morbidity and growth: A randomised trial from Guinea-Bissau

Measles, mumps, and rubella vaccine at age 6 months and hospitalisation for infection before age 12 months: randomised controlled trial

OBJECTIVE

To test for potential non-specific effects of an additional, early measles, mumps, and rubella (MMR) vaccine at age 5-7 months on risk of infection related hospitalisation before age 12 months.

DESIGN

Randomised, double blinded, placebo controlled trial.

SETTING

Denmark, a high income setting with low exposure to MMR.

PARTICIPANTS

6540 Danish infants aged 5 to 7 months.

INTERVENTIONS

Infants were randomly allocated 1:1 to intramuscular injection with standard titre MMR vaccine (M-M-R VaxPro) or placebo (solvent only).

MAIN OUTCOME MEASURES

Hospitalisations for infection, defined as all hospital contacts of infants referred from primary care for hospital evaluation and with an infection diagnosed, analysed as recurrent events, from randomisation to 12 months of age. In secondary analyses implications of censoring for date of subsequent diphtheria, tetanus, pertussis, polio, Haemophilus influenzae type B, and immunisation with pneumococci conjugate vaccine (DTaP-IPV-Hib+PCV), potential effect modification by sex, prematurity (<37 weeks' gestation), season, and age at randomisation were tested, and the secondary outcomes of hospitalisations ≥12 hours and antibiotic use were evaluated.

RESULTS

6536 infants were included in the intention-to-treat analysis. 3264 infants randomised to MMR vaccine experienced 786 hospitalisations for infection before age 12 months compared with 762 for the 3272 infants randomised to placebo. In the intention-to-treat analysis the rate of hospitalisations for infection did not differ between the MMR vaccine and placebo groups (hazard ratio 1.03, 95% confidence interval 0.91 to 1.18). For infants randomised to MMR vaccine compared with those randomised to placebo, the hazard ratio of hospitalisations for infection with a duration of at least 12 hours was 1.25 (0.88 to 1.77), and for prescriptions of antibiotics was 1.04 (0.88 to 1.23). No significant effect modifications were found by sex, prematurity, age at randomisation, or season. The estimate did not change when censoring at the date infants received DTaP-IPV-Hib+PCV after randomisation (1.02, 0.90 to 1.16).

CONCLUSION

Findings of this trial conducted in Denmark, a high income setting, do not support the hypothesis that live attenuated MMR vaccine administered early to infants aged 5-7 months decreases the rate of hospitalisations for non-targeted infection before age 12 months.

TRIAL REGISTRATION

EU Clinical Trials Registry EudraCT 2016-001901-18 and ClinicalTrials.gov NCT03780179.

A narrative review of nonspecific effects of pediatric vaccines on child mortality and morbidity

We reviewed evidence on nonspecific effects of pediatric vaccines on mortality and morbidity in countries with high child mortality. Literature search of epidemiological studies was conducted for studies published between 2000 and September 2021 using MEDLINE. Consistent evidence exists regarding the potential protective effect of measles vaccine on child survival. Vaccination with Bacillus Calmette-Guérin (BCG) vaccine was related to lower risk of mortality in young children (including low birth weight babies) and inverse associations were found between developing a scar and having a positive tuberculin test after BCG vaccination with mortality. BCG vaccine might also reduce the risk of nontuberculosis infectious diseases. Studies on the association between diphtheria-pertussis-tetanus (DPT) vaccine and child survival showed inconsistent findings, which might be affected by bias and confounding. More evidence is needed to assess the role of these and other vaccines in children's health and to better understand potential biological mechanisms and other influential factors.

Reduction in Short-term Outpatient Consultations After a Campaign With Measles Vaccine in Children Aged 9-59 Months: Substudy Within a Cluster-Randomized Trial

BACKGROUND

We assessed a measles vaccination campaign's potential short-term adverse events.

METHODS

In a cluster-randomized trial assessing a measles vaccination campaign's effect on all-cause mortality and hospital admission among children aged 9-59 months in Guinea-Bissau, children received a measles vaccination (intervention) or a health check-up (control). One month to 2 months later, we visited a subgroup of children to ask mothers/guardians about outpatient consultations since enrollment. In log-binomial models, we estimated the relative risk (RR) of nonaccidental outpatient consultations.

RESULTS

Among 8319 children (4437 intervention/3882 control), 652 nonaccidental outpatient consultations occurred (322 intervention/330 control). The measles vaccination campaign tended to reduce nonaccidental outpatient consultations by 16% (RR, 0.84 [95% confidence interval {CI}, .65-1.11]), especially if caused by respiratory symptoms (RR, 0.68 [95% CI, .42-1.11]). The reduction tended to be larger in children who prior to trial enrollment had a pentavalent vaccination (diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenzae type b) as the most recent vaccination (RR, 0.61 [95% CI, .42-.89]) than in children who prior to trial enrollment had a routine measles vaccination as the most recent vaccination (RR, 0.93 [95% CI, .68-1.26]) (P = .04 for interaction).

CONCLUSIONS

In the short term, a measles vaccination campaign seems not to increase nonaccidental outpatient consultations but may reduce them.

CLINICAL TRIALS REGISTRATION

NCT03460002.