Mortality risk among frail neonates might be associated with maternal BCG scar status: Observational study from Guinea-Bissau

Effects of Neonatal BCG-Japan Versus BCG-Russia Vaccination on Overall Mortality and Morbidity: Randomized Controlled Trial From Guinea-Bissau (BCGSTRAIN II)

Background

Vaccination with the Danish strain of bacille Calmette-Guérin (BCG) has been associated with pronounced reductions in all-cause neonatal mortality and morbidity. Developing a skin reaction postvaccination is associated with markedly reduced mortality risk. It is unknown whether the beneficial nonspecific effects are maintained across different BCG strains.

Methods

This was an open-label randomized controlled trial in Guinea-Bissau, comparing BCG-Japan (n = 8754) versus BCG-Russia (n = 8752) for all-cause hospital admission risk by 6 weeks of age (primary outcome) and 6 months of age. Additional secondary outcomes were in-hospital case-fatality risk (CFR), all-cause mortality, and BCG skin reaction prevalence. Participants were followed through telephone calls at 6 weeks and 6 months, with a subgroup also visited at home. We assessed admission and mortality risk in Cox models providing incidence rate ratios (IRRs) and mortality rate ratios. CFR and skin reactions were assessed by binomial regression providing risk ratios. Analyses were done overall and stratified by sex.

Results

BCG strain was not associated with admission risk, the BCG-Japan/BCG-Russia IRR being 0.92 (95% confidence interval [CI], .81-1.05) by 6 weeks and 0.92 (95% CI, .82-1.02) by 6 months. By 6 months of age, there were significantly fewer BCG-Japan infants with no skin reaction (1%) than for BCG-Russia (2%), the risk ratio being 0.36 (95% CI, .16-.81). BCG-Japan skin reactions were also larger.

Conclusions

Both vaccines induced a skin reaction in almost all participants. The BCG strains had comparable effects on morbidity and mortality, but BCG-Japan was associated with more and larger skin reactions that are indicators of lower mortality risk.

Clinical Trials Registration

NCT03400878.

Can earlier BCG-Japan and OPV vaccination reduce early infant mortality? A cluster-randomised trial in Guinea-Bissau

OBJECTIVE

To assess the effect of providing BCG and oral polio vaccine (OPV) at an early home visit after delivery.

DESIGN

Cluster-randomised trial, randomising 92 geographically defined clusters 1:1 to intervention/control arms.

SETTING

Bandim Health Project Health and Demographic Surveillance System, Guinea-Bissau.

PARTICIPANTS

2226 newborns enrolled between July 2016 and August 2019.

INTERVENTIONS

In both arms, newborns received a home visit within 72 hours after birth. In intervention clusters (n=46), BCG and OPV were provided at the home visit.

MAIN OUTCOME MEASURE

Rates of non-accidental mortality were compared in Cox proportional hazards models from (last of) day 1 or enrolment, until (first of) day 60 or registration of non-trial vaccines.

RESULTS

A total of 35 deaths (intervention: 7, control: 28) were registered during the trial. Providing BCG and OPV reduced non-accidental early infant mortality by 59% (8-82%). The intervention also reduced non-accidental hospital admissions. The intervention had little impact on growth and BCG scarring and tended to increase the risk of consultations.

CONCLUSIONS

The trial was stopped early due to lower-than-expected enrolment and event rates when 33% of the planned number of newborns had been enrolled. Despite the small size of the trial, the results support that early BCG and OPV vaccinations are beneficial and reduce early child mortality and morbidity.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT02504203).

BCG and SARS-CoV-2-What Have We Learned?

Despite controversy over the protective effect of the BCG (Bacille Calmette-Guérin) vaccine in preventing pulmonary tuberculosis (TB) in adults, it has been used worldwide since 1921. Although the first reports in the 1930s had noted a remarkable decrease in child mortality after BCG immunization, this could not be explained solely by a decrease in mortality from TB. These observations gave rise to the suggestion of nonspecific beneficial effects of BCG vaccination, beyond the desired protection against M. tuberculosis. The existence of an innate immunity-training mechanism based on epigenetic changes was demonstrated several years ago. The emergence of the pandemic caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2) in 2019 revived the debate about whether the BCG vaccine can affect the immune response against the virus or other unrelated pathogens. Due to the mortality of the coronavirus disease (COVID-19), it is important to verify each factor that may have a potential protective value against the severe course of COVID-19, complications, and death. This paper reviews the results of numerous retrospective studies and prospective trials which shed light on the potential of a century-old vaccine to mitigate the pandemic impact of the new virus. It should be noted, however, that although there are numerous studies intending to verify the hypothesis that the BCG vaccine may have a beneficial effect on COVID-19, there is no definitive evidence on the efficacy of the BCG vaccine against SARS-CoV-2.