Overview
Definition:
HIV-exposed infants are newborns born to mothers living with HIV
Prophylaxis refers to the use of antiretroviral drugs (ARVs) to prevent HIV infection in these infants
Testing involves serial HIV testing to determine the infant's infection status.
Epidemiology:
Globally, vertical transmission of HIV remains a significant concern, although rates have dramatically decreased with effective antiretroviral therapy (ART) in pregnant women
In India, despite progress, continued vigilance and adherence to prophylaxis and testing protocols are crucial
The risk of transmission without intervention can range from 15-45%.
Clinical Significance:
Timely and appropriate prophylaxis significantly reduces the risk of perinatal HIV transmission, protecting infants from a chronic, life-limiting illness
Early and accurate diagnosis through timely testing allows for prompt initiation of treatment, improving long-term outcomes and preventing the development of AIDS-related opportunistic infections and complications.
Prophylaxis Strategy
Perinatal Arv Prophylaxis:
Antiretroviral prophylaxis for the infant is initiated as soon as possible after birth, ideally within 6-12 hours
The regimen depends on the mother's viral load and ART status during pregnancy and delivery
Three-drug prophylaxis is generally recommended for infants born to mothers with detectable viral load or unknown status.
Infant Arv Regimens:
Standard prophylaxis for infants includes zidovudine (AZT) for 4-6 weeks
For higher-risk infants (e.g., born to mothers with detectable viral load, premature birth, or intrapartum exposure), a three-drug regimen is used, typically including zidovudine, lamivudine, and a protease inhibitor (e.g., nelfinavir) or an integrase inhibitor (e.g., raltegravir), for 6 weeks
Combination prophylaxis has demonstrated higher efficacy.
Duration And Discontinuation:
Prophylaxis is typically continued for 4-6 weeks
Discontinuation is considered after negative virologic testing at specific time points, and if all tests remain negative, the infant is considered uninfected
If any test is positive, further evaluation and treatment are initiated.
Breastfeeding Recommendations:
In resource-rich settings, breastfeeding is discouraged due to the risk of HIV transmission through breast milk
However, in settings where safe alternatives are not feasible, exclusive breastfeeding for the first 6 months, along with continued infant ARV prophylaxis and maternal ART, may be considered
Indian guidelines generally recommend formula feeding or avoidance of breastfeeding if feasible.
Testing Approach
Infant Virologic Testing:
Virologic tests are used to detect HIV DNA or RNA and are the gold standard for diagnosing HIV infection in infants
Initial testing is recommended at birth (for high-risk infants), 14-21 days, 1-2 months, and 4-6 months of age
Nucleic acid amplification tests (NAATs) like PCR are preferred.
Diagnostic Thresholds:
A positive virologic test (e.g., HIV-1 DNA PCR or HIV-1 RNA) at any time point after 48 hours of age is diagnostic of HIV infection
Two separate positive virologic tests are required for definitive diagnosis, with the first test ideally performed at or after 14 days of age and the second at or after 1 month of age.
Serologic Testing:
Antibody tests (ELISA, rapid antibody tests) are not reliable for diagnosing HIV infection in infants younger than 18 months due to the persistence of maternal antibodies
These tests are used for initial screening of the mother and for confirmation of infection in older children.
Infant Follow Up Schedule:
A comprehensive follow-up schedule is crucial
This includes serial virologic testing at specific intervals (e.g., birth, 2 weeks, 1 month, 4 months) and antibody testing at 18 months for definitive confirmation of non-infection if all previous virologic tests were negative
Clinical assessment for signs of HIV infection should also be performed at each visit.
Management Of Hiv Infected Infants
Initiation Of Art:
Infants diagnosed with HIV infection should be initiated on antiretroviral therapy (ART) immediately
Early initiation of ART is critical for immune reconstitution and preventing disease progression and mortality.
Pediatric Art Regimens:
Recommended first-line ART regimens for infants and children typically include two nucleoside reverse transcriptase inhibitors (NRTIs) plus a non-nucleoside reverse transcriptase inhibitor (NNRTI) or a protease inhibitor (PI)
Specific regimens are based on age, weight, and potential drug resistance
For example, a common regimen may include zidovudine or tenofovir, lamivudine, and efavirenz or lopinavir/ritonavir.
Monitoring And Supportive Care:
Regular monitoring of viral load, CD4 count, growth, development, and adherence to ART is essential
Supportive care includes nutritional support, prophylaxis for opportunistic infections (e.g., Pneumocystis jirovecii pneumonia), and immunizations
Management of co-infections and psychosocial support for the family are also vital components.
Challenges And Considerations
Adherence To Prophylaxis And Testing:
Challenges include ensuring timely administration of prophylaxis, adherence to the complex testing schedule, and socioeconomic factors that may hinder access to care
Education and support for caregivers are paramount.
Drug Resistance:
Drug resistance can arise from suboptimal maternal ART adherence or infant prophylaxis
Genotypic resistance testing may be indicated in cases of treatment failure or suspected resistance.
Stigma And Disclosure:
Addressing stigma associated with HIV is important for families
Disclosure of the infant's HIV status to caregivers and, at an appropriate age, to the child, requires careful and sensitive communication.
Resource Limitations:
In resource-limited settings, access to rapid diagnostic tests, a wide range of ARVs, and skilled healthcare providers can be challenging
Strategies to optimize care within available resources are crucial.
Key Points
Exam Focus:
Understand the risk stratification for infant prophylaxis based on maternal viral load
Memorize the recommended infant prophylaxis regimens and duration
Recall the specific timing and types of virologic tests for infant diagnosis
Know the criteria for definitive diagnosis of HIV infection in infants
Differentiate between virologic and serologic testing in this age group.
Clinical Pearls:
Initiate infant prophylaxis within 6-12 hours of birth, regardless of maternal ART status
Ensure accurate documentation of maternal ART history and infant exposure
Counsel caregivers thoroughly on the importance of adherence to prophylaxis and the testing schedule
Coordinate with the mother's care team
Consider gestational age and birth weight when selecting prophylaxis.
Common Mistakes:
Delaying infant prophylaxis
Relying solely on antibody tests for diagnosis in infants under 18 months
Inadequate counseling on breastfeeding implications
Failing to follow up with serial virologic testing as per guidelines
Incorrect interpretation of early test results.