Quoting Erin Berlin:" Not sure how preemie your baby is, but my son was born at 36+2 and that night in the hospital he met ... [snip!] ... touched raw meet, or anything else REALLY dirty). He's pretty sturdy. Knock on wood of course. He will be 6 weeks old tomorrow."
I really depends on the baby though and the season.
8 weeks is when my daughter crashed with RSV and pneumonia, since she wasn't really a preemie, we thought she was sturdy enough to be ok. I mean no one really thinks their kid is going to get it.
You also have to take into consideration, do you have an older child in school, that really ups it too. Going the grocery store and family's houses once or twice isn't going to make much of a difference if your keeping him in a car seat, people are washing their hands etc...
But a child in school comes home every day with germs of tons of people. And I believe that's how my daughter got sick. Plus the cold and flu season was horrible that year. My mother in law had a cold for over a month.
This season has also been reported as one of the worst for flu. And colds are bad this year too.
It's up to you what you do with your baby, but I obviously learned my lesson. Even if I have another 37 weeker, if the cold and flu season is bad, we're not leaving for like a month or 2 until it's over. Having your child not be able to breath, crying because they're hungry and they just want to nurse, and being hospitalized for 8 days is not worth you taking them out.