While access to paediatric antiretroviral treatment has expanded globally resulting in a substantial decline in mortality rates in HIV-infected children, a new study warns that HIV is now evolving into a chronic illness among adolescents.
Researchers, in findings published in The Lancet medical journal this week, say longstanding HIV infection acquired when the immune system was not developed results in distinctive chronic clinical complications that cause severe morbidity.
In addition to dealing with chronic illness, the study observes that HIV-infected adolescents have to confront psychosocial issues, maintain adherence to drugs, and learn to negotiate sexual relationships while undergoing rapid physical and psychological changes.
The study says global epidemiology of paediatric HIV affects more than three million children worldwide with nine out of ten of those infected living in sub-Saharan Africa.
Unlike the rapid widespread implementation of highly effective HIV interventions in industrialised countries that began in the mid 1990s, antiretroviral treatment for prevention of mother-to-child HIV transmission only became available in much of Africa around 2004.
The study notes that while in sub-Saharan Africa the number of infant infections has dropped by 24% from 2009 to 2011, treatment coverage remains suboptimum, with only 59% of HIV-infected pregnant women receiving antiretroviral treatment to prevent mother-to-child transmission in the 21 high-burden countries, and about 1000 infants were infected daily in 2011.
In population-based HIV prevalence surveys in southern Africa, HIV prevalence of 2ÔÇö6% was reported consistently among adolescents, before antiretroviral treatment became available. Up to age 14 years, no difference in HIV prevalence by sex is evident, inferring a non-sexual route of HIV acquisition. Researchers note however, that in children older than 14 years, prevalence of HIV is disproportionately higher in girls than in boys, reflecting the well-recognised increased risk of HIV infection through sexual transmission in young women compared with young men.
The study says HIV-infected adolescents are susceptible to vaccine-preventable illnesses, which typically have the greatest effect on young children. A lower response rate to early childhood immunisations, and waning immunity after early vaccination, are likely causes; in outbreak situations, HIV-infected adolescents can be especially vulnerable.
Of 195 HIV-infected children identified with measles in an outbreak in Botswana in 2009ÔÇö10, the median age was 13 years. The most severely affected patients were HIV-infected adolescents, most of whom had been immunised against measles during early childhood.
In a study of young people age 8ÔÇö17 years in Rwanda who received hepatitis B vaccinations, amounts of HIV RNA and CD4 counts were both independent predictors of hepatitis B antibody response.
Scientists say revaccination could restore immunity, although the study says currently no robust evidence is available to support this. Human papillomavirus (HPV) is associated strongly with cervical cancer, and HPV infection rates in Africa are said to be high.
Findings of a study in Tanzania showed that 65% of adolescent girls acquired HPV within one year of sexual debut. The HPV vaccine has proven safe, immunogenic, and acceptable to adolescents and their guardians. However, policies about HPV vaccination are still being developed for most countries in sub-Saharan Africa.
