WINNIPEG - Researchers say they are closer than ever to finding a vaccine against HIV/AIDS thanks to people who have had contact with the virus but haven't become infected.
Case studies were shared at a gathering of about 75 international experts in Winnipeg on Monday with the hope of getting another step closer to beating the virus that attacks the immune system.
Dr. Frank Plummer, director of Winnipeg's National Microbiology Laboratory, said he expects to see a vaccine in his lifetime.
"I'm confident that we will get there eventually," Plummer said. "It's not a simple problem. If it was, we would have done it already."
In September, researchers announced that a two-vaccine combination cut the risk of becoming infected with HIV by more than 31 per cent in a trial of more than 16,000 volunteers in Thailand.
Key to developing a vaccine lies in cases around the world of people who have had contact with the virus but haven't become infected, Plummer said.
Researchers at the conference pointed out that many breast-feeding infants who are born to HIV-positive women escape infection. Some groups of sex-trade workers who are repeatedly exposed to the virus also appear to be immune.
"Sometimes that's because of luck but sometimes that's because, I believe, they're immune in some way to HIV," Plummer said.
"I think we understand more and more about immunity to HIV and how it works and why some people don't get infected after they are exposed.
"We don't understand it fully yet and that needs to be expanded. We don't understand how to produce it artificially, which is what a vaccine is all about."
Canada's chief public health officer, Dr. David Butler-Jones, said some of the greatest vaccine discoveries have come from deciphering natural immunity.
"The original vaccine for smallpox was a recognition that milk maids who had cowpox were not susceptible to smallpox," he said.
Although some of the world's great minds are grappling with the virus, Butler-Jones said it is a very difficult illness to crack. People are capable of developing antibodies to HIV/AIDS but they aren't enough to protect against the virus.
"It is one of the great scientific and medical challenges moving forward. Every day we are one day closer but exactly when that day will come, it's impossible to predict.
"The sooner, the better."
