All you can do is be as vigilant as possible.
Although I don't smoke now, I did for about 40 years, heavily. Me lungs are probably as black as a blind cobbler's thumb so I'm not keen on getting this thing. Everytime I go out, I keep my hands away from my face, the second I arrive home I lock my front door, spray the internal door handle and keys with antibacterial aerosol and scrub my hands thoroughly.
I tend to go shopping very early, 8-9 AM.
I take my dog out daily and will cross the road if someone coming towards me on my side.
I pay for petrol at the pump.
I push open doors with my shoulder or pull them open with my hand inside my sleeve so as not to touch door handles, likewise those slide-top freezers.
I have a few cloths permantly soaking in a strong bleach solution which I use to give a quick wipe over on stuff I've brought into the house like plastic milk bottles, plastic trays of meat etc, no one knows who or how many people have picked it up in the hours or mins before I bought it. After shopping put away then wash hands and I'm fairly confident I'm clean but no one knowsfor certain
glad I'm not the only one who feels like that, I'm pure para, got copd, hands are raw with washing and bleaching everything, skins dry, but my partner works for nhs, has to come in, go straight into loo, to shower, change and put laundry in machine, in the meanwhile i'm washing handle on outside door both sides, bathroom door, then shes allowed in, wash any notes coins, car keys, even though she has wiped the steering wheel ect down before coming in, oh and the mobile phone, the list just goes on, but ,better safe than sorry