IV. The Challenge of Diagnosis

Despite the rapid expansion of PMTCT programs, not all mothers are reached by them, and some children become infected despite them. An essential first step in caring for HIV-infected children is accurate and early diagnosis of HIV.

Pediatric HIV Diagnosis

Accurately diagnosing HIV in infants and children is a major challenge. Children who are infected with the virus before birth, at birth, or through breastfeeding may not exhibit any symptoms of HIV infection or AIDS.

HIV can be diagnosed in adults by testing blood for antibodies to HIV. In children, however, an antibody test is not effective, because the mother�s maternal antibodies are passed to the child as a natural means of protection while the infant is developing its own immune system. As a result, antibody tests for infants may yield false positive results for up to 18 months.

In the absence of early infant diagnosis, most HIV-exposed infants are lost to follow-up and 50% of untreated HIV-positive infants die before their second birthday.  Many die before accurate HIV antibody testing can be performed at 15-18 months; therefore, early infant diagnostic testing is a priority for the Emergency Plan.

Strengthening laboratory support for testing

An important method for diagnosing HIV in children is a polymerase chain reaction (PCR) test, also known as a viral load test, for virus in an infant�s blood cells. With Emergency Plan support, many host nations are beginning to use this technology to improve accuracy and timeliness of infant diagnosis.

PCR testing can be conducted on either whole blood or dried blood spots (DBS) from infants. DBS is a simple, inexpensive approach in which a small stick is performed on the child�s foot and the blood is dripped onto filter paper. The DBS specimen can easily be transported in a sealed bag or envelope to a lab where the specimen is tested for HIV using PCR technology. In contrast to whole blood, DBS does not always require refrigeration, can be easily transported, is relatively inexpensive, and requires less blood from the infant. By providing accurate and early diagnosis of infants, DBS offers promise for more timely access to lifesaving treatment and care services for infants who are infected, and is now being practiced or planned in a number of Emergency Plan countries.

One challenge is that the type of laboratory which can support sophisticated PCR equipment is often only available at a referral point or center of excellence, although blood samples can be taken from more remote locations and brought into the central laboratory.

Laboratory support under the Emergency Plan has focused on working with host country governments and counterparts to develop and strengthen a network of laboratories based on a tiered model of services. This model envisions reference laboratories and centers of excellence at centralized locations that provide support, including quality assurance, to more remote health centers with limited laboratory capacity. All 15 focus countries now have PCR capability. It should be noted, however, that PCR testing in the focus nations in still in its early stages, so there is very limited data available on PCR testing programs at this time.

Botswana: Using new technologies for HIV testing in children

In 2005, 200 health care workers from 12 Francistown clinics and the regional hospital for northern Botswana were trained in DBS collection for early infant diagnosis of HIV by a U.S. Government team. A laboratory technician in the HIV reference laboratory in the capital city of Gaborone was also trained to perform PCR on the samples. During the first month, 236 HIV-exposed infants from the clinics and regional hospital were tested. In the clinics, 6% of infants were HIV-positive; in the hospital, 15% were positive. This corresponds with modeling data from the PMTCT program suggesting that overall HIV transmission to infants within Botswana's antenatal care system is 9-11%. Infants found to be HIV-positive are being referred to the national antiretroviral treatment program for therapy.

In Uganda, the government has designed a national infant testing program which will include family-based testing in the near future. Initially, the program will use a U.S. Government-supported central laboratory for all testing. As the program becomes more widespread, additional reference laboratories will be established. The program will focus initially on PMTCT programs and children of people with HIV, and offers the promise of increased diagnosis of children through family-based testing.

To improve laboratory services for both children and adults, the Emergency Plan obligated $25,464,675 in FY2004, and $58,620,461 is planned for FY2005. It is not possible to determine the amount that has been specifically dedicated to pediatric HIV/AIDS.

Support for diagnosis based on clinical signs and symptoms

By supporting host governments to improve their laboratory infrastructure, the Emergency Plan has facilitated infant diagnosis. Laboratory testing, however, is still not universally available. Thus, under the Emergency Plan, the U.S. Government has worked with WHO and UNICEF to develop simplified staging and treatment guidelines for children appropriate for resource-poor settings.

The Emergency Plan also supports training in clinical diagnosis as a component of physician and nurse training. Through an increase in the number of sites, and an improvement in the capacity to diagnose children with HIV, the Emergency Plan has increased the number of entry points for enrolling children into treatment.

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