Journal Club - BCG vaccine still effective and protective in newborns

Given in countries with endemic TB, BCG vaccine has surprisingly been found to protect newborns and young infants against multiple bacterial and viral infections unrelated to TB. There's even some evidence that it can reduce severity of COVID-19.

A recent study, published in Cell Reports, found that the BCG vaccine induces specific changes in metabolites and lipids that correlate with innate immune system responses. The findings provide clues toward making other vaccines more effective in vulnerable populations with distinct immune systems, such as newborns.

Using metabolomics and lipidomics, researchers profiled the impact of BCG immunization on the newborns' blood plasma. They found that BCG vaccines given at birth changed metabolite and lipid profiles in newborns' blood plasma in a pattern distinct from those in the delayed-vaccine group.

The changes correlated with changes in cytokine production, a key feature of innate immunity. Study used blood samples from low-birthweight newborns who were enrolled in a randomized clinical trial to receive BCG either at birth or after a delay of six weeks. Both groups had small blood samples taken at four weeks.

Researchers concluded that BCG vaccine protects against unrelated infections, It's critical to learn from BCG for better understanding how to protect newborns. BCG is an 'old school' vaccine made from a live, weakened germ but live vaccines like BCG seem to activate the immune system in a very different way in early life, providing broad protection against a range of bacterial and viral infections.