Someone advised the Vatican side is not quite as safe as the Coliseum side. Shall I be concerned since I did find an available hotel (the Hotel Silla)on the Vatican side.

Gee I hope I was clear in my message request. Is the Vatican side safe?

I haven't personally encountered any problems on the Vatican side of the river while wandering around a good bit. I also haven't read any authoritative opinions that say it is more dangerous. I'd suspect the relative safety depends on the specific area, not on a general position on one side of the river or the other. I think it would be more appropriate to ask on this forum whether anyone believes the specific hotel you chose is in a safe area, or whether a safe route exists from there to your other destinations. Good luck.

The Hotel Silla is, logically enough, on the Via Silla, which seems to be in the Prati area of Rome. I have never heard Prati referred to as "less safe" than any other area of Rome (but there certainly are other areas of Rome that are not considered safe; as a rule, though, they are not areas that a tourist would have any reason to visit.) Prati is, as I recall it (I stayed there on the Via Alessandro Farnese, five or six streets closer to the Tiber than Via Silla, many years ago), a largely upper middle class residential area. Via Silla runs into Via Cola di Rienzo, which is a major shopping street (not high-end designer boutiques like in the Via Condotti/Piazza di Spagna area but more in the mid-price range).

The only reason that I can think of to see it as "less safe" is that there is relatively little life on the streets in the evening, compared to an area like Piazza Navona/Pantheon, which is full of restaurants and cafes and heavily frequented until late in the evening.

Thank you for your help, makes me feel better. My husband and I probably won't be roaming at night so seems it will work out.