It was also before mass production of penicillin. Venereal diseases like syphilis and gonorrhea were a much bigger deal back then.

Agreed.

For the record, it is very hard to contract HIV from vaginal sex. (< 1/10000 per-instance chance)

That's exaggerating quite a bit; but more importantly leaving off the other half of the equation — it's a lot easier for a woman to contract it from a man.

True, women are more likely to get it from a man than vice-versa, but my number (1 in 10k) is not exaggerating all that much.

http://hivinsite.ucsf.edu/insite?page=ask-05-10-11

"Two large studies in California and Europe found a per-contact risk (meaning the risk of a man becoming infected from each instance of penile-vaginal sex) of 0.0001 (1 in 10,000) and 0.0003 (1 in 3,000)"

Didn't they already have Penicillin during WW2? I think the story must have taken place after WW2? But maybe it wasn't mass produced, military only or something.

They had it, but it wasn't mass-produced, and nearly all doses went to soldiers on the front that had suffered injuries or amputations. There wasn't enough for ordinary infections - they'd even collect the urine of soldiers being dosed so that excreted penicillin could be distilled and re-used.

I figure that the story took place either during the war or slightly after (late 1940s). Penicillin wasn't mass-produced and available to consumers until the 1950s.