Improved implementation of a combination of HIV prevention strategies is urgently needed to effectively curb the global HIV epidemic that is seeing 2.5 million new infections per year with 40 million cases expected by 2016, academics said at the 11th Taipei International Conference on HIV/AIDS.
The building blocks of a comprehensive combination of HIV prevention strategies include testing, education, condom availability and the prevention of mother-to-child transmission (PMTCT), along with treatment as prevention and pre-exposure prophylaxis (PrEP), said Thomas Quinn, director of the Johns Hopkins Center for Global Health.
Quinn said that PMTCT is the prevention method most capable of achieving the greatest success within the shortest period of time.
“If you get a pregnant woman on antiretroviral drugs [ARVs] or even after delivering while she’s breastfeeding to continue ARVs with PrEP ... in the infant, you can essentially reduce transmission by over 95 percent from mother to infant,” Quinn said.
In Taiwan, 99 percent of pregnant women are screened for HIV and since 2007, the number of HIV-positive mothers has remained in the single digits, Centers for Disease Control official Chen Chang-Hsun (陳昶勳) said.
Administering ARV prophylaxis to both mothers and newborns has led to no babies from HIV-infected mothers testing positive for the virus in the period from 2009 to last year, Chen said.
It is from this effective approach “that an ‘AIDS Free Generation’ terminology started to be launched and started to be promoted,” Quinn said.
The same biomedical knowledge can be used to block sexual transmission, be it male-to-male or heterosexual, as “one of the common biological factors that is consistent, whether it’s mother-to-child transmission or sexual transmission, is viral load,” Quinn said.
The greater the viral load, the greater the risk of transmission.
In mother-to-child transmission, for every log increase in viral load — 1,000,000 copies/ml plasma — in the mother, there is a two-and-a-half-fold increased risk of transmission to the infant. The same is true for couples in which one partner is HIV-positive and the other is not, Quinn said.
On a broader level, a recent study showed that “as you increase the proportion of all HIV-infected people receiving ARVs from less than 10 percent in the population to more than 40 percent, you get a decline in HIV acquisition in the community as a whole,” he said.
Antiretroviral therapy (ART) is therefore a crucial and effective prevention strategy, but the problem in both the US and Taiwan — manifested in an “HIV care cascade” — is that only a small proportion of HIV-infected individuals receive such care.
In Taiwan, while the CDC estimates that about 29,000 people have HIV, only 71 percent of them, or 20,468 people, know they are infected, Chen said. Only 62 percent are receiving some form of HIV care, 57 percent more complete care, 43 percent are on ART and 36 percent have a suppressed viral load.
More widespread ART, to be applied in combination with other prevention measures, is therefore a key intervention and prevention approach for ending the epidemic, and will succeed “only if adherence to medication and behavioral change are emphasized,” Quinn said.
In a panel discussion at the conference, speakers were asked to comment on how legalizing same-sex marriage, an issue currently being debated in Taiwan, might impact the behavior of men who have sex with men and HIV rates.
Kenrad Nelson, a professor at John Hopkins University’s Bloomberg School of Public Health strongly supports it.
“I think legalizing same-sex marriage is a very important public health intervention. We want men who have sex with men to have single partners and yet we won’t let them get married and have all the legal rights of the heterosexuals? I think that’s counterproductive from a public health standpoint,” Nelson said, adding that the public health value of legalizing gay marriage has been greatly underemphasized.