HIV-1 LTR subtype and perinatal transmission

Area of Science:

• Virology
• Epidemiology
• Public Health

Background:

• Human Immunodeficiency Virus type 1 (HIV-1) exhibits diverse subtypes globally.
• Limited data exists on the comparative transmissibility of different HIV-1 subtypes, particularly in mother-to-infant transmission.
• Understanding subtype-specific transmission dynamics is crucial for effective prevention and control strategies.

Purpose of the Study:

• To investigate the relative transmissibility of different HIV-1 long terminal repeat (LTR) subtypes during mother-to-infant transmission.
• To determine if specific HIV-1 LTR subtypes are associated with increased or decreased perinatal transmission rates.

Main Methods:

• A matched case-control study design was employed.
• Long terminal repeat (LTR) subtypes were determined for 45 matched mother-infant pairs from a clinical trial in Tanzania.
• Statistical analysis using exact matched logistic regression was performed to assess transmission probabilities.

Main Results:

• HIV-1 subtypes A, C, and intersubtype recombinant sequences were identified.
• Viruses with subtype A or intersubtype recombinant LTRs were 3.2 and 4.8 times more likely to be transmitted perinatally compared to subtype D.
• Subtype C LTRs were associated with a 6.1-fold increased likelihood of mother-to-infant transmission versus subtype D.
• These transmission differences were independent of maternal CD4 cell counts at enrollment.

Conclusions:

• HIV-1 subtype appears to be a significant factor influencing perinatal transmission rates in Tanzania.
• Specific HIV-1 subtypes (A, C, and recombinants) demonstrate higher transmissibility than subtype D.
• Findings highlight the need to consider HIV-1 subtype in the development of targeted interventions for preventing mother-to-infant transmission.