Even as medical researchers are making advances and poorer countries are reducing their rates of infections, people in developed nations have grown complacent and allowed gonorrhea, syphilis and other sexually transmitted diseases to spread again, an expert warns.
Speaking Wednesday to scientists gathered in Toronto for the country's foremost science honour, the Gairdner Awards, Dr. King Holmes spoke of the need to remain vigilant as he gave fellow researchers a global picture of the fight against AIDS and other sexually transmitted infections.
"We have an increasing number of tools but we need to be more effective … We can do a much better job with the tools we have," Dr. Holmes said in an interview at the Gairdner Annual Global Health Symposium.
A researcher at the University of Washington in Seattle, Dr. Holmes is an authority in fighting sexually transmitted diseases. He is one of the 2013 recipients of the Gairdners, which have a track record of anticipating future Nobel Prize winners.
The symposium heard several examples of the ephemeral nature of medical success against sexually transmitted diseases.
Myron Cohen, a professor of medicine, microbiology and epidemiology at the University of North Carolina at Chapel Hill, worked in China in the 1970s and recalled that its Maoist government had virtually eradicated syphilis.
"It was a remarkable achievement that couldn't have been done anywhere but in China," Dr. Cohen said.
And yet, he noted, as it reopened its borders and developed into an economic power, China became the country with the world's worst rate of syphilis.
David Lewis, a researcher with the National Institute of Communicable Diseases in Johannesburg, gave a presentation that reviewed how gonorrhea, which was once countered by the discovery of penicillin, has now developed strains with extreme resistance to antibiotics.
"The pathogens are smarter than we are. As we make changes, they adapt," Dr. Holmes said.
One promising path has been the emergence of better immunization tools, he said, citing the vaccines for hepatitis B and human papillomavirus as examples.
Another promising discovery came from the HIV Prevention Trials Network 052 study led by Dr. Cohen.
HPTN 052 found that early treatment with antiretroviral therapy reduced HIV transmission in couples. It was hailed by the journal Science as its 2011 breakthrough of the year.
Still, even that study shed light on the difficulty in persuading people to adopt safer behaviour. Participants were counselled on safer sex and condom use. There were nevertheless 234 pregnancies.
"Either there's an outbreak of immaculate conception or people are telling you what's socially desirable," Dr. Cohen said.
Dr. Holmes said rates of HIV remain high in developed countries despite new treatments, a sign that not enough prevention is done.
"Expert diagnosis and treatment for those who show up at your clinics is essential, but this alone is a drop in the bucket," he said, alluding to the need to fight "condom fatigue" in high-risk groups.
These setbacks are occurring as infection rates are decreasing in lower-income countries, he noted.
Dr. Holmes's presentation underlined how the spread of syphilis, genital herpes and chancroid have significantly decreased in South Africa, Kenya and India.
"Will STI [sexually transmitted infections] epidemics accelerate even further in [gay men] and other populations at high risk? Will the resurgence of STIs again increase transmission of HIV?" Dr. Holmes asked in his presentation.
"What will be the impact of increasing unprotected sex on emergence of new STIs?"
The symposium took place in the same week Leger Marketing released a survey of 1,500 Canadian university students showing that only half of them reported using a condom even though 72 per cent of them engaged in intercourse during their last sexual encounter.
A quarter also believed that a vaccine is now available to prevent HIV, according to the survey, which was conducted between Dec. 6, 2012, and Jan. 2, 2013, for the condom maker Trojan and the Sex Information and Education Council of Canada.
According to the Public Health Agency of Canada, the rate of gonorrhea in Canada dropped steadily in the 1980s and 1990s, in part because people became more cautious because of the emergence of AIDS. However, after reaching an all-time low in 1997, gonorrhea rates began to climb again.
Reported rates of chlamydia, gonorrhea and infectious syphilis have all mushroomed in the past decade.