Aussie researchers say their findings could have major global impacts, especially in low-income countries.
Administering the RV3-BB rotavirus vaccine at birth significantly boosts the levels of beneficial gut bacteria in newborns, enhancing their early protection against infection, researchers have found.
The Murdoch Children’s Research Institute study, published in Nature Communications, paves the way for a promising strategy to combat severe rotavirus gastroenteritis, especially in low-income countries where the disease remains a major cause of childhood death.
MCRI and University of Melbourne Professor Julie Bines said understanding the interaction between gut microbiome and the protection provided by the RV3BB vaccine was key to informing new dosing schedule options within national immunisation programs.
The MCRI Enteric Disease Research Group, led by Professor Bines, developed the RV3-BB vaccine, which has been proven to be safe and effective in clinical trials in Australia, New Zealand, Indonesia and Malawi.
Professor Bines said the study found the response to the RV3-BB vaccine when given from birth was linked to the balance of both “good” and “bad” bacteria in the gut microbiome.
“A strong vaccine response was greater in babies with a higher proportion of ‘good’ bacteria while it was lower in babies with more potential disease-causing bacteria,” she said.
“This tells us that providing the vaccine as soon as possible after birth, before babies are exposed to ‘bad’ bacteria in their environment, may help avoid the challenges to the response of oral rotavirus vaccines, particularly in low-income countries.
“Babies who received the RV3-BB from birth also sustained a healthy gut microbiome for much longer compared to those who didn’t receive the vaccine. This further suggests the vaccine may have a positive effect on the development of the early gut microbiome.”
As part of the study, researchers analysed stool samples from nearly 300 babies in Indonesia and Malawi, comparing those vaccinated from birth to others who received their first dose at the conventional age of six to eight weeks.
The gut microbiome, the bacteria, viruses and fungi, found in a healthy gut assist with digestion and regulation of the immune system. At birth the gut microbiome is relatively immature, providing a unique timepoint where the microbiome presents less of challenge to the uptake of orally administered vaccines such as RV3-BB.
“The newborn gut differs structurally and functionally from the mature gut,” the MCRI researchers wrote.
“The first weeks after birth are also acknowledged as a critical period in the development of the gut microbiome as the newborn responds to the ex-utero environment.”
MCRI senior research officer Dr Josef Wagner said the results showed the timing of the first dose of RV3-BB was important to optimise vaccine response.
“Gut microbiome plays a crucial role in your health by helping to control digestion and supporting immune, heart and brain health,” he said.
“The newborn gut develops over the first months of life in response to feeding, antibiotic and environmental exposure.
“Our findings suggest, the RV3-BB vaccine, when given at birth, may help shape the early gut microbiome in a way that improves the body’s response to the vaccine. Importantly, administering the vaccine at birth may provide a window of opportunity to target the first dose, which could improve vaccine uptake and provide early protection.”
Rotavirus is the most common cause of severe diarrhoea in children under five years of age, causing more than 230,000 deaths every year, mainly in low-income countries. But despite the wide-reaching impact, barriers remain including the timely administration of a full two or three dose schedule (routinely given from six weeks of age), program costs and safety concerns.
To make a rotavirus vaccine more readily accessible, MCRI has made RV3-BB rotavirus vaccine available to manufacturers for license to produce vaccines at a large scale for an accessible price.
