11.   And even if an extraordinarily effective vaccine, akin to the polio vaccine, is developed, it will take decades to eradicate HIV.

12.   And it would have been a one-time event because standard polio vaccines were not made from chimpanzee tissues.

13.   Attenuated virus vaccines, like the Sabin oral polio vaccine, are similar to the disease-causing versions except that they have lost the genetic capacity for virulence.

14.   After the polio vaccine was proved successful in the field trials, Salk became a hero to the public.

15.   After Jonas Salk invented a polio vaccine, the journalist Edward R. Murrow asked him who owned the patent.

16.   Alison Schneider follows the progress of a patient who had this quick, bloodless and precise procedure, which may catch on like the polio vaccine.

17.   But Hooper theorizes that chimpanzees were also used to prepare the experimental polio vaccine.

18.   Here she is giving a dose of polio vaccine to a toddler in Congo.

19.   Health workers look for children during a sweep of the region in July to administer the polio vaccine.

20.   Hooper suggested that the contamination might have come from an experimental oral polio vaccine prepared at the Wistar institute, a research center in Philadelphia.