Live virus vaccines use a weakened virus to help your body fight the real disease. Some people, like those who are very sick or pregnant, should not get live virus vaccines. A live virus vaccine ...

Besides serving as food for certain microbes, viruses perform some helpful functions that remain poorly understood. A ciliate, a type of single-celled microbe, swims next to Sphagnum moss, amplified ...

Viroids are tiny strands of circular, infectious RNA. They differ from viruses in that they do not have a protective protein coat and that they do not encode any proteins of their own. They are also ...

The world is absolutely teeming with viruses. The infectious agents are widely considered the most abundant biological entity on Earth. But a full understanding of viruses and the roles they play in ...

Using genomics, evolutionary biologists test several hypotheses on the origin of viruses. New evidence suggests they may have emerged more times than previously thought. Corroborating the virus-first ...