11.   At the end of the trial, researchers will compare the infection rate of the placebo group with that of the vaccine group.

12.   A range of AIDS prevention programs is credited by CDC officials for a more favorable trend in infection rates in the United States.

13.   Across the region, young people have been exposed to more education about HIV and condoms than their elders, yet they have the highest infection rates.

14.   AIDS has remained largely an urban epidemic in America, but infection rates have been rising rapidly in rural areas.

15.   AIDS is also a threat in prisons, where there are no condoms available and the infection rate is high.

16.   All states are required to report cases of AIDS, but several states with relatively high HIV infection rates, including California, do not report cases of HIV.

17.   But AIDS shots might be standard elsewhere in the world, in areas where HIV infection rates are much higher than they are in this country.

18.   But engagement in organizations is down, and infection rates are up, and the AIDS epidemic is nowhere near over in the gay community.

19.   But the disease remains rampant and deadly in many developing nations where infection rates continue at alarming rates and treatment is minimal.

20.   But researchers say that in places like Botswana and South Africa, where infection rates are high, even a partly effective vaccine can make a big difference.