A virus that causes the infection is described as virulent as upon the release of virion progeny, the host cell is lysed or broken apart to allow the progeny virions to go out of the host cell and infect other cells
The virus upon infecting a host does not immediately kill the infected cell but instead allows its genetic material to be incorporated into the host cell's genome. The viral infection is latent (hidden), until it is transduced and activated to eventually switch on to the lytic cycle.
Learning about the basic concepts of viral infection makes us better understand medical interventions done to combat COVID-19 such as the production of vaccines