Although the delineations aren’t always clear-cut, the immune system’s responses to pathogens can be roughly grouped into three categories: type 1, which is directed against viruses and certain bacteria that infiltrate our cells; type 2, which fights parasites like worms that don’t invade cells; and type 3, which goes after fungi and bacteria that can survive outside of cells. Each branch uses different cytokines to rouse different subsets of molecular fighters.
The Coronavirus Outbreak ›
Frequently Asked Questions
Updated August 4, 2020
I have antibodies. Am I now immune?
- As of right now, that seems likely, for at least several months. There have been frightening accounts of people suffering what seems to be a second bout of Covid-19. But experts say these patients may have a drawn-out course of infection, with the virus taking a slow toll weeks to months after initial exposure. People infected with the coronavirus typically