The number of adolescent deaths from AIDS has tripled over the last 15 years with 26 new infections occurring every hour, according to the the UN Children's Fund (Unicef).

The Unicef report said AIDS is the number one cause of death among adolescents in Africa and the second leading cause of death among adolescents globally.

World over, 2.6 million children in the age group 0-14 were living with HIV in 2014.  About half of adolescents (15-19) living with HIV are in just six countries: South Africa, Nigeria, Kenya, India, Mozambique and Tanzania

The situation in Asian countries is also alarming. Some 50,000 Asian teens (aged 15-19) became HIV-positive in 2014 alone, and a total of 220,000 adolescents were living with HIV in the region.

AIDS-related deaths of teenagers in Asia increased a horrifying 110 percent from 2005 to 2014, while deaths of adults went down 28 percent. Deaths of teenagers from AIDS nearly quadrupled in South Asia, from 1,500 in 2001 to 5,300 in 2014, according to the report.

"Those who are HIV-negative must have access to the knowledge and means to help them to stay that way," said Craig McClure, head of UNICEF's global HIV/AIDS programmes, at a conference in Johannesburg, South Africa, where new data was released by UNICEF.

In sub-Saharan Africa, the region with the highest prevalence, girls are vastly more affected, accounting for 7 in 10 new infections among 15-19 year-olds. UNICEF also said among adolescents in sub-Saharan Africa, just over 1 in 10 is tested for HIV.

"Among HIV-affected populations, adolescents are the only group for which the mortality figures are not decreasing," according to UNICEF.

According to the data in UNICEF's Statistical Update on Children, Adolescents and AIDS, less than half of children under 2 months old are tested for HIV. Only 1 in 3 of the 2.6 million children under the age of 15 living with HIV is on treatment.

Most adolescents who die of AIDS-related illnesses acquired HIV when they were infants, 10 to 15 years ago, when fewer pregnant women and mothers living with HIV received antiretroviral medicines to prevent HIV transmission from mother to child. "These children have survived into their teenage years, sometimes without knowing their HIV status," UNICEF said.

On a positive note, the new data shows that since 2000, nearly 1.3 million new infections among children have been averted, largely due to advances in the prevention of mother-to-child transmission of HIV.

"The gains we have made on preventing mother to child transmission are laudable, and to be celebrated," McClure added, "but immediate investments are needed to get life-saving treatment to children and adolescents who are infected."

The UN report thinks that the"explosion of smart phone gay dating apps" like Grindr allows increased risk-taking among young people so that they have sex at a younger age with more partners, and using condoms less often, because it's so easy to find an immediate sex partner using an app.