The most dangerous strains are those that display resistance to multiple antibiotics. (sciencedaily.com)
«The standard vaccines that are in current use are safe and effective, and not prone to cause the emergence of more dangerous strains of viruses. (washingtonpost.com)
Ironically, increased virulence would make it even more important to vaccinate everyone, he says, because universal vaccination would prevent the more dangerous strains from harming anyone. (sciencemag.org)