The second dose of a COVID-19 vaccine induces a powerful boost to a part of the immune system that provides broad antiviral protection, according to a study led by investigators at the Stanford University School of Medicine. The findings published in the journal Nature strongly supports the view that the second shot should not be skipped."Despite their outstanding efficacy, little is known about how exactly RNA vaccines work," said Bali Pulendran, PhD, professor of pathology and of microbiology and immunology.