My 2 siblings and I grew up in a North Carolina home where the houses we could afford were pretty small. Since we had actual seasons, the mid fall through mid Spring usually required the doors and windows to be closed -- if not all the time, at least at night when the temps dropped. The Winter months rarely got warm enough to open the windows. Once we got A/C, though, the opening of windows was not as frequent, particularly in the hot days of Summer.
My mother and grandmother were chain smokers. If you don't know what that means, it's when they light the next cigarette off the current one before putting the current one out. On days when they both were in the kitchen, it was seriously hard to see through the smoke.
I one painted the living room myself. Before I could, I had to was the walls with bleach to remove a 1/8-inch film of slick, brown tarry crap! That's the stuff that was going into all our lungs.
That was all before people started standing outside to smoke to avoid complaints by nonsmokers.
After about 55 years, I'd think at least one of us three would have had lung problems or cancer if secondhand smoke was all that dangerous. So far, none of us has any sign of related problems.
One could argue that going to school most of the year on weekdays and leaving at age 18-ish would be mitigating factors, but then that begs the obvious question: what's the maximum exposure time to secondhand smoke before you are in danger? What about the frequency? Concentration of smoke in the room (number of smokers & cigarettes smoked).
I submit that if you eat out 4 days a week, go to a club once or twice a month, and don't smoke, the chances of any secondhand smoke related illness is less than the chances of adverse side effect from the vaccine. The concentration, duration and frequency of exposure will be so minor, your body will be able to cleanse itself of any toxins long before the next exposure.