The Victory's twice as long as a modern carrier (and one quarter the mass, and half the aircraft), but what about crew size? I haven't been able to find any info on that quicklike. I would wildly guess it at about four or five hundred, since it's one of Confed's smaller carriers. Modern carriers (as well as the big WW2 flavor) have 5k-6k people. Modern naval vessels with crews in the hundreds often do not have doctors aboard.
Though since the Victory did have 3 other ships grouped with it, and since it's less likely that those three ships had doctors while the Victory did not, that the Victory might well have some MDs aboard to serve the whole group.
@Shipgate: I don't think that seeing medics of some kind really indicates that the doctor:crew ratio of the given ship is above zero.
I don't think there's anything crazy about some educated conjecture in an area of Wing Commander we don't really know much about. Isn't that what these forums are best at? : )
Let's put it more simply - in the games (WC2 in particular), we hear of doctors. In the novels, we also hear of doctors or see them in their natural setting. We're also talking about the fact that these ships are engaged in combat and do not always have a base or a well-equipped hospital to fall back on should they have serious casualties, nor are those bases often within an hour's flight from the carrier groups or lone capships if there are problems. Therefore, we've both the reason to have doctors -and- have been given indicators that they're present. Arguing that doctors aren't present is like arguing that a current United States Navy carrier doesn't have a PX or a barber shop, just because you never see them on TV or something, but you've only heard that they exist and have read about them.
Beyond which, you're still arguing apples and oranges - yes, many vessels have only corpsmen or medics aboard. However, that's because they're not designed to travel by themselves, nor are they ever too far away from medical assistance if it's necessary, be it in the middle of combat or in the middle of a peacetime cruise. Good hospital facilities are only an hour or so worth of flight time away, be it the carrier which forms the nuclear of a battle group, or a land-based facility of either an allied nation or a USN base.
In Wing Commander, just crossing between planets can take a few hours - and we're not even counting the fact that the fighting may take place in contested and depopulated systems. Yes, many people will not survive due to environmental conditions outside, and pilots are particularly vulnerable to it. However, people onboard the ship may get wounds which will let them live for at least a few minutes, assuming that their section doesn't vent out or get fried by enemy fire. There are also things like landing accidents, ejected pilots who are wounded, and perhaps a support ship having been evacuated with some of their crew collected by a carrier's S&R group. At the very least, the carriers do have decent medical facilities, and I suspect the cruisers do too - at least, the Austin had a psych ward.