It goes without saying a virology lab of this level isn’t the same as most organizations. Given the nature of their activities they have safety systems in place to prevent a virus from spreading at the work place.
This is a silly assertion. Precautions are taken against the viruses being studied in the labs themselves - gloves, hoods, special suits if you're working with something like Ebola - but when you go to the cafeteria or visit someone's office, it's unlikely people were masking or distancing etc. pre-COVID.
Colds/flus likely spread like they do at any other workplace.