A new vaccine against HIV, to be tested in a trial to be launched in South Africa Wednesday, could be "the final nail in the coffin" for the disease if it is successful, scientists say.

A 44-year-old British man hopes that he may be the first person to be cured of HIV, and doctors who have worked on the new therapy are hopeful.

Four HIV-infected children treated right after birth show no detectable virus but its resurgence in a fifth who stopped medication means it's too soon to talk of an HIV "cure," say Canadian researchers.