What step is necessary in order for a microscopic virus to truly invade the human body?

A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 6,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is forced to rapidly produce thousands of identical copies of the original virus

Explanation:

just put in mind that others aren't perfect. we all have problems that we feel makes us low of the low. but know that you are special and unique, that is what makes you out of this world : ). you might think and feel that others judge you, but mostly other people are scared if people judge them. just be happy, spend time with family, smile because that is the greatest medicine. a happy life. hope this : ))

does it have options?