[AlexandrB]

Only if the virus makes its presence known quickly. Something can be fatal, yet take months or years to kill you.

Worst case would be a highly lethal, airborne virus with a long delay between infection and death.

[learc83]

Viruses tend not to work like that because to effectively spread via respiratory droplets and aerosols they require a high viral load in the respiratory system. This generally causes symptoms.

I’m sure it’s not completely impossible, but neither is a massive radiation burst from a nearby supernova.