How we are born - by Caesarean-section or vaginal delivery - alters how our immune system responds to vaccines, a Scottish and Dutch study suggests.

Babies born vaginally had double the level of protective antibodies produced after childhood vaccines.

The researchers said the difference was caused by the types of good bacteria, which colonise our bodies at birth.

And while C-section babies do get protection, it may need topping up with probiotics or extra vaccines.

Our birth is the moment we emerge from the sterile world of the womb to one teeming with microscopic life.

Microbes - including bacteria, fungi, viruses and archaea - make our bodies home and eventually outnumber our "human" cells.

This hidden half of ourselves is known as the microbiome and one of its roles is training our immune system early in life.