A new vaccine technique could make it possible for doctors to administer effective vaccinations to newborns, closing an existing window of opportunity for infection and helping less developed countries fight infectious diseases. According to figures from the Global Health Council, more than 15 million people die from infectious diseases every year. The vast majority of these diseases occur in poor, developing countries, and young children are disproportionately affected.
While a few vaccines, such as that for hepatitis B, are given at birth, most children don’t start receiving vaccinations until they are 2 months old, after which they receive a series of vaccines at regular intervals until their inoculations are complete.
The reason newborns aren’t given the majority of vaccines is because their immune systems aren’t developed enough for those vaccines to take effect.
“Vaccines are approved for use for specific age ranges,” said Ofer Levy, a physician and infectious disease researcher at Children’s Hospital Boston. “A lot of vaccines are less effective for newborns.”
Vaccines work by introducing into the body harmless molecules that trick the immune system into thinking it’s fighting an infection, causing it to produce the antibodies necessary to fight off harmful versions of the disease it encounters in the future.
Newborns’ immune systems in particular have less ability to produce protein molecules known as cytokines that tell disease-fighting cells what to do, making it difficult for their immune systems to learn from vaccines.
In a new study, Levy and colleagues Sarah Burl and Katie Flanagan, at the Medical Research Council in the Gambia, wanted to see whether they could induce a newborn’s immune system to produce more of these cytokines, potentially making vaccines more effective.
Levy’s team took blood samples from 120 Gambian infants ranging from zero to 12 months of age and exposed the blood to chemicals that stimulate a variety of receptors on white blood cells called Toll-like receptors.
Two chemicals that stimulated the receptors known as TLR8 and TLR4 seemed to spur these white blood cells to produce more cytokines — even in the newborns’ blood. That suggests that the immune systems of newborns who received vaccines paired with these chemicals would be better prepared to learn immunity from the vaccines. The researchers reported their results this week in the Public Library of Science ONE.
Making vaccines more effective for newborns is extremely important in resource-poor countries like the Gambia, Levy said, where opportunities to see doctors are rare.
“Vaccination at birth is very practical from a public health standpoint,” he said. “That’s statistically the most likely time for someone to receive medical attention.”
Making the most out of that opportunity by vaccinating newborns has the potential to save many lives, Levy said.
Within the year, he and his colleagues plan to begin testing this technique on newborn monkeys before they move to human trials.
Lance Gordon, president and CEO of the biotechnology company ImmunoBiologics Corp. in Framingham, Mass., agrees that the technique will be particularly useful in developing vaccines that target diseases that affect young children in poor countries. The immune systems of newborns in the Gambia are very different from those of newborns in New York City, most likely because of differences in nutritional background, Gordon said, speaking from the World Vaccine Congress just outside Washington this week.
The ability to give newborns’ immune system a jump-start is a good example of the ways in which scientists are increasingly able to adapt vaccines for different purposes, he said. “We’re getting more and more sophisticated with our vaccines.”
