How to protect my USB drive against viruses after install Kali Linux on this USB key ?

I would like to know if I install Kali on a USB stick (as USB sticks are often vulnerable to virus infections), if the virus will not attack this quickly and destroy my laptop installation of Kali ???

There is not a better way to install Kali on a key without that key is subsequently infected with viruses later, virus infection that could attract the destruction of my installation of Kali ???

Thank you to inform me please.