Cultural sensitivities about sexual activity mean girls are missing out on access to many HIV/Aids programmes, which often reach sex workers and older women but not younger girls.
That gap in programme access is one of the problems that Link Up - a new initiative launched by a consortium of international and national NGOs led by the International HIV/Aids Alliance - is looking to tackle.
In Sub-Saharan Africa, women and girls are as much as eight times more likely than their male peers to be living with HIV. Divya Bajpai, a senior advisor on sexual and reproductive health for the International HIV/Aids Alliance, describes that statistic as "staggering".
Divya is part of the team responsible for Link Up, which is aiming to improve the sexual/reproductive health and rights (SRHR) of more than one million young people living with and affected by HIV, including 600,000 girls across five countries in Africa and Asia.
"Being a girl impacts on the rate, pace and impact of HIV," explains Divya. "Just by being a female, there are higher risks of having HIV, starting with the fact that women and girls are biologically more susceptible to HIV infection than men and boys."
Link Up, which started in January 2013, wants to empower 10-24 year-old girls and women to become confident, knowledgeable youth leaders to demand and access quality, user friendly integrated SRH and HIV services and to demand for their sexual and reproductive rights to be upheld. "We're not going to be duplicating what's out there, but we do think there's a missing link and a gap in both the HIV and SRHR responses," says Divya.
That gap is made up of younger girls living with and vulnerable to HIV who are often left out - or fall out - of SRHR programmes because of the sensitivities and cultural taboos around sex and HIV. Divya explains: "It's really hard for young women to walk into a clinic without feeling they're a bad person. Unless you fit the profile of a married woman of reproductive age, you're often stigmatised by health care providers.
"Young girls and young women are hindered by factors such as community attitudes, early marriage, acceptance of gender-based violence and stigma and discrimination if you are living with HIV, are pregnant, sell sex or use drugs."
Link Up is funded by the Dutch Ministry of Foreign Affairs, BUZA. It will provide education and counselling on SRHR and HIV to young women and men, work with civil society and governments to deliver improved services, protect the rights of young people affected by HIV and gather evidence around what works when integrating sexual and reproductive health and rights to HIV programmes with marginalised young people.
Through start up visits and consultations led by partners, Divya and the rest of the Link Up team are developing intervention packages by consulting the girls first hand. "We heard directly from young girls, so that we could find out the gaps from them," she says.
"Safer sex counselling is just one intervention - adapting each solution to the age, gender, vulnerabilities and risks faced by anyone who walks through the door is how we will make sure the programme works."
Divya is confident that identifying and talking to girls who are left out of other programmes is essential to breaking the intergenerational cycle of poverty. "Link Up is really filling a gap for vulnerable girls and women," she says.
Find out more about Invisible Girls and where the gaps in data are