<P> There is currently no cure or effective HIV vaccine . Treatment consists of highly active antiretroviral therapy (HAART) which slows progression of the disease . As of 2010 more than 6.6 million people were taking them in low and middle income countries . Treatment also includes preventive and active treatment of opportunistic infections . </P> <P> Current HAART options are combinations (or "cocktails") consisting of at least three medications belonging to at least two types, or "classes," of antiretroviral agents . Initially treatment is typically a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus two nucleoside analog reverse transcriptase inhibitors (NRTIs). Typical NRTIs include: zidovudine (AZT) or tenofovir (TDF) and lamivudine (3TC) or emtricitabine (FTC). Combinations of agents which include protease inhibitors (PI) are used if the above regimen loses effectiveness . </P> <P> The World Health Organization and United States recommends antiretrovirals in people of all ages including pregnant women as soon as the diagnosis is made regardless of CD4 count . Once treatment is begun it is recommended that it is continued without breaks or "holidays". Many people are diagnosed only after treatment ideally should have begun . The desired outcome of treatment is a long term plasma HIV - RNA count below 50 copies / mL . Levels to determine if treatment is effective are initially recommended after four weeks and once levels fall below 50 copies / mL checks every three to six months are typically adequate . Inadequate control is deemed to be greater than 400 copies / mL . Based on these criteria treatment is effective in more than 95% of people during the first year . </P> <P> Benefits of treatment include a decreased risk of progression to AIDS and a decreased risk of death . In the developing world treatment also improves physical and mental health . With treatment there is a 70% reduced risk of acquiring tuberculosis . Additional benefits include a decreased risk of transmission of the disease to sexual partners and a decrease in mother - to - child transmission . The effectiveness of treatment depends to a large part on compliance . Reasons for non-adherence include poor access to medical care, inadequate social supports, mental illness and drug abuse . The complexity of treatment regimens (due to pill numbers and dosing frequency) and adverse effects may reduce adherence . Even though cost is an important issue with some medications, 47% of those who needed them were taking them in low and middle income countries as of 2010 and the rate of adherence is similar in low - income and high - income countries . </P>

Which of the following is the most common mode of hiv transmission in canada in 2012