I think that depends on whats going around. If there is an Ebola outbreak in the country, i would not kiss strangers or work at all.Right, but there are many many "ordinary" diseases (including some deadly ones) that you can get from kissing and exchanging saliva, including all of the ones that can be transmitted by coughing and sneezing (which spray tiny saliva droplets into the air and onto other people). It is sort of surprising that people don't worry more about getting diseases from kissing (whether in a p4p or np4p context) if they are going to worry about STDs. I suspect it is simply because STDs seem scarier and are more stigmatized.
-Ww
If flu is really going around i may be extra wary, try to make sure someone is not under the weather before kissing.
However, the general risks of colds and flu dont bother me and I haven’t had the flu in years.