The effect of early measles vaccination at 4.5 months of age on growth at 9 and 24 months of age in a randomized trial in 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.

Vaccination Coverage: Vaccine-Related Determinants & Anthropometric Measures in Children Resident in a Rural Community in Nigeria

BACKGROUND

Vaccination of children has played a significant role in reducing early childhood morbidity and mortality from vaccine-preventable diseases; however, some factors act as deterrents in achieving adequate coverage in this susceptible population.

AIMS & OBJECTIVES

The study, therefore, aimed to identify vaccine-related determinants of childhood vaccination as well as determine the relationship between childhood vaccination status and body weight, height, and a child's body mass index (BMI).

METHODS

The study was conducted using a cross-sectional design in which 608 caregiver-child pair was recruited sequentially by using a two-stage sampling technique. Structured questionnaires based on the SAGE vaccine hesitancy model were used to interview the participants. Elicited data was analyzed and categorical variables were presented in tables and charts as frequencies, while a chi-square test was used to test the association between the independent and dependent variables. Pearson's correlation analysis was also done to determine the correlation between vaccination status and weight, height, and BMI of children.

RESULT

The study showed that vaccination coverage was suboptimal (70.56%) in children and was below the expected target of 80%. Although a few (183, 30.10%) of the respondents claimed they would prevent the vaccination of their children due to the fear of needles, the majority (87.50%) will be willing to accept more vaccine doses for their children if there were no pain. While factors such as the experience of adverse reaction (X2 = 13.22, df = 2, p<0.001), crying from pain (X2 = 11.33, df = 2, p<0.001) and the scientific evidence of safety (X2 = 34.63, df = 2, p<0.001) were significantly associated with a complete vaccination status, vaccination status was positively correlated with the weight (r=0.160, p<0.001), height (r=0.081, p=0.023) and BMI (r=0.214, p<0.001) of children in the rural community.

CONCLUSION

Vaccination uptake and coverage can be significantly improved in children by designing and implementing interventional programs that target pharmaceutical and vaccine-specific factors acting as barriers in these rural communities.

Waning of Maternal Antibodies against Measles Suggests a Large Window of Susceptibility in Infants in Lao People's Democratic Republic

Introduction: Measles is an endemic but largely neglected disease in Lao People’s Democratic Republic. New-borns are protected by maternal antibodies, but antibody waning before measles vaccination at 9 months of age leaves infants susceptible to infection. In this study, the susceptibility window of infants was determined to generate scientific evidence to assess the national measles immunization strategy. Methods: Between 2015 and 2016, demographic data, medical history, and blood samples were collected from 508 mother-child pairs at the provincial hospital in Vientiane. The samples were screened with a commercial kit detecting anti-measles IgG antibodies. Results: The large majority (95.7%) of the mothers were seropositive for anti-measles IgG and antibody titers of the mothers and infants were highly correlated (p < 0.01). While at birth 97.7% of the infants were seropositive, seropositivity rates decreased to 74.2% two months later to reach only 28.2% four months after birth (p < 0.01). Just before the first dose of the measles-rubella vaccine, scheduled at 9 months of age, was actually given, less than 14% of the infants were seropositive. Conclusion: This alarmingly wide susceptibility gap due to rapid maternal antibody decay leaves infants at risk of measles infection and serious disease complications. A high herd immunity is crucial to protect young infants and can be achieved through improved routine vaccination coverage and (expanded age group) supplementary immunization activities.

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

BACKGROUND

Measles vaccine (MV) has beneficial non-specific effects protecting against non-measles infections in some situations. Within a trial of the effect of MV on mortality, we assessed effects of early MV on the secondary outcomes consultations and growth, overall, and by sex and exposure to campaigns with oral polio vaccine (OPV).

MATERIALS AND METHODS

Children were randomly assigned to MV at 4.5 + 9 months or MV at 9 months as recommended. At enrolment and 9 months children had their mid-upper-arm-circumference (MUAC) and weight measured. Consultations (out/inpatient) were registered at monthly home visits. Weight-for-age and MUAC-for-age Z-scores were obtained using the WHO growth reference and compared by group in linear regression models. Consultation rates between enrolment and 9 months were compared in Cox proportional hazards models, providing consultation Hazard Ratios (HRs) for early MV versus no early MV. We tested whether the effect of early MV was modified by OPV campaigns by splitting observation time at exposure to OPV campaigns.

RESULTS

Among 3548 children enrolled between 2012 and 2015, early MV had no effect on MUAC-for-age (mean difference comparing early MV vs. no MV -0.01, 95% CI -0.06-0.04), weight-for-age (mean difference -0.03, 95% CI -0.07-0.02) or rates of consultations (HR = 1.03, 95% CI 0.92-1.16). The rate of consultations for children enrolled was lower after exposure to OPV campaigns (HR = 0.81, 95% CI 0.71-0.92). The effect of MV differed before exposure to OPV campaigns (HR = 1.12, 95% CI 0.98-1.29) and after OPV campaigns (HR = 0.83, 95% CI 0.67-1.03) (test for interaction: p = 0.03). Associations did not differ by sex.

CONCLUSION

Early MV had no overall effect on consultation rates and growth between enrolment and 9 months of age. However, early MV tended to have beneficial effects for children subsequently exposed to OPV campaigns. As beneficial effects were observed in subgroups, the results should be interpreted with caution.

CLINICAL TRIALS REGISTRATION

NCT01644721.

Head-to-head immunogenicity comparison of Edmonston-Zagreb vs. AIK-C measles vaccine strains in infants aged 8-12 months: A randomized clinical trial

BACKGROUND

A non-inferiority multi-centre parallel randomized double-blind trial was implemented in Zahedan district, Sistan-va-Baluchestan province, Iran, to compare the performance of the two measles vaccines which are in use in the National Immunization Programme of Iran and are of two different measles virus vaccine strains: Edmonston-Zagreb (EZ) strain vs. AIK-C strain. The main outcome measure was appearance of anti-measles antibody in sera.

METHODS

200 infants, 8-12 months old, whose parents consented for their children to be included in the study, were randomized in permutation blocks of size 4-8 in four Urban Health Clinics. Having given a pre-vaccination blood sample, they received measles-rubella vaccine containing one of the vaccine strains mentioned before. After 60 days, the second blood sample was taken. The sera of the pre- and post-vaccination blood samples were tested for anti-measles antibodies in the National Reference Measles Laboratory. Parents, laboratory technicians and statistician were blind to groupings.

RESULTS

Of the 200 children equally randomized in the two arms, 185 who were seronegative before vaccination (88 in the EZ arm and 97 in the AIK-C arm) were entered in the final analysis. The seroconversion rate in the EZ arm was 76.1% (95% CI: 60.2-85.2%), and that in the AIK-C arm was 58.7%; (95% CI: 48.8-68.7%). The absolute rate difference was 17. 4% (4.1-30.9%; P-value: .012), and the relative seroconversion rate of EZ to AIK-C was 1.3 (95% CI: 1.1-1.6; P-value: .012). No adverse events were reported during the study period.

CONCLUSION

A considerable difference in the seropositivity of different measles containing vaccines could be demonstrated in the first year of life.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials Registration Number: IRCT2016032827144N1; May 10, 2016 (www.who.int/ictrp/network/irct/en/).