Congenital HIV Infection and its Prevention

See also: related article on Childhood AIDS.

HIV infection in young children most commonly arises as a result of vertical transmission (or mother to child transmission – MTCT)., Other routes of infection such as precocious intravenous drug use or sexual abuse/activity should be borne in mind as rarer scenarios, and become increasingly common as children approach adolescence. It is thought that only 1.5–2% of MTCT occurs transplacentally during pregnancy.¹ The vast majority occurs due to maternofetal transmission of blood during parturition or post-natal breastfeeding.

Correct management using anti-retrovirals, the correct method of delivery and avoidance of breastfeeding can massively reduce the chances of MTCT in a given pregnancy. Unfortunately, the prevailing socio-economic conditions in many parts of the world most severely affected by HIV and AIDS are such that these measures are currently difficult to implement. Political as well as medical will is needed to reduce the worldwide incidence of unnecessary congenital HIV infection, to reduce the burden of disease caused by this global pandemic.

Even in the developed world, one cannot afford to be complacent as there is no guarantee that patients will comply with screening and treatment programs, even if they are available.²

In the UK, the unlinked anonymous surveillance programme of 2006 revealed that 1 in 440 women giving birth in England and Scotland were HIV-positive. The prevalence outside London has increased eightfold between 1997 and 2006.. Sub-Saharan African born pregnant women living outside London had a significantly higher HIV prevalence (3.5%) in 2006 than those living inside London (2.1%).The prevalence of HIV in UK born women has increased by 66% from 1997 to 2006. Voluntary confidential reporting mechanisms found 1,650 cases of HIV-infection in children under15, with 77% of these cases due to MTCT. It was estimated that in 2006 about 90% of all HIV-infected women giving birth in England and Scotland were diagnosed before delivery due to the routine offering and recommendation of antenatal HIV-testing.

A study at the UCL Institute of Child Health found that Injecting drug use as the reported risk factor for maternal HIV acquisition declined from 49.2% in 1990-1993 to 3.1% in 2004-2006.³
The WHO estimates that in 2003 there were ~700,000 worldwide cases of childhood HIV infection. The overwhelming majority of these were due to MTCT.⁴ A massive proportion of these cases occurred in relatively impoverished countries. HIV-seroprevalence rates in pregnant women in developing countries can be as high as 5%.⁵ Approximately 30% of HIV-positive mothers will transmit the infection to their children if they receive no treatment.⁶

In the US, the annual incidence of MTCT of HIV is estimated at 1,400–2,200 cases, with a HIV seroprevalence rate of around 0.3% among pregnant women, predominantly affecting metropolitan centres.⁵ US perinatal HIV-transmission rates are 25% and 4% in untreated and treated women respectively.⁵ Recent figures from Sweden have shown a fall in transmission rates from ~25% in 1985–1993, to 0.6% in 1999–2003, as management of this clinical scenario has improved.⁷

Hopefully, most cases of UK-based HIV infection in pregnant mothers will be picked up before delivery so that HIV infection of the child is unlikely/anticipated. However, up to 10% of HIV-positive mothers have slipped through the system in relatively recent times, so appropriate vigilance and suspicion of HIV-infection in unwell children is important. When undetected it may occur as an early infection if transmitted transplacentally or perinatally, or later if transmitted through breastfeeding. Some cases present with an indolent course in later childhood, despite infection having occurred in the fetal, perinatal or infant stages.

Signs of HIV in children

There are no specific HIV signs, but those present are usually due to disease caused by opportunistic infection. Signs may be found in the following systems:

• Growth/development. Falling off on growth centile charts.
• Dermatological. Erythematous, papular rash due to HIV dermatitis. Shingles rash. Candidal dermatitis with marked erythema. Purpura/bruising in rare cases of HIV-induced thrombocytopenia.
• Head, eye, ears, nose and throat (HEENT). Parotid enlargement, large tonsils, oral aphthous ulcers, oral/pharyngeal plaques due to thrush or leukoplakia, CMV retinitis.
• CVS. Signs of congestive cardiac failure due to cardiomyopathy. Peripheral oedema can also be caused by hypoalbuminaemia due to HIV nephropathy or malnutrition due to gastrointestinal dysfunction.
• RS. Crackles, wheeze and other non-specific findings can be present in PCP pneumonia or Mycoplasma pneumoniae infection - signs of cavitation/lung abscess in cases of TB/cavitating pneumonia (including finger clubbing).
• Abdomen. Hepatomegaly and splenomegaly are relatively common findings in HIV-infected children.
• Reticuloendothelial. Persistent generalised or regional lymphadenopathy or gross lymphadenitis due to lymphoma.
• CNS. Motor delay, abnormalities of muscle tone, spastic diplegia and oral motor dysfunction are signs of HIV encephalopathy. Opportunistic CNS infection can present in a variable fashion.

• Causes of growth impairment or failure to thrive.
• Causes of developmental delay or regression.
• Other causes of childhood anaemia ± immunosuppression.
• Bruton's agammaglobulinaemia or transient hypogammaglobulinaemia of infancy.
• Common variable immunodeficiency.
• Causes of lymphadenopathy.
• Intestinal malabsorption.
• Neglect or malnutrition of child.
• Infectious mononucleosis.
• Severe combined immunodeficiency.
• Thymic aplasia.
• Primary tuberculosis.
• Metabolic childhood disease, eg organic acidurias.
• Primary dermatological disease.
• Cystic fibrosis.

Expectant mothers should be offered routine screening for HIV infection during pregnancy. Those with positive results should be referred to a centre with expertise in managing her HIV diagnosis and the pregnancy in order to reduce the likelihood of MTCT. Children with HIV may need extensive investigation.

In the developed world the mainstays of management of HIV-infected pregnant women are:

Prevention is far better than cure where HIV and children is concerned. Outlook is significantly worse for children with congenital HIV infection when compared to those infected in later life, despite the enormous advances in prophylactic and anti-opportunistic-infection treatments. Mean survival from diagnosis is about 10 years. About 15% of children suffer rapidly progressive and fatal disease with the remainder split between those with a more chronic course and those who appear to be similar to adults in their ability to tolerate HIV infection and its treatment.⁵ The tragedy of HIV infection in the developing world is underlined by the fact that 20% of babies born with HIV infection will die before their 4th birthday without treatment, and 50% will not survive past their 9th birthday without treatment.

Key strategies include:

• Prevention of primary HIV infection in women and the prevention of unintended pregnancies in women living with HIV⁶
• Offering and high uptake of routine antenatal HIV-testing for pregnant women
• Adequate management of cases of known HIV in pregnancy and those picked up by screening
• Wholesale worldwide politico-social changes that address the scarcity of general and HIV-specific healthcare resources in the developing world¹⁸