Mother-to-Child HIV Transmission

Infectious Diseases Society of America Annual Meeting

Harvey S. Bartnof, MD

The following reports concerning women and mother-to-child HIV transmission were presented at the Infectious Diseases Society of America (IDSA) annual meeting in San Francisco, September 13-16, 1997 or the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Toronto, Ontario, September 28-October 1, 1997. See also Selected Highlights from Recent Conferences in this issue.

Pregnant Women may Obtain Abortions after False Positive Toxoplasmosis Results

• The Food and Drug Administration (FDA) issued a Public Health Advisory letter July 25, 1997. Copies may be obtained by calling 301-594-3060 or sending e-mail to mtz@cdrh.fda.gov
• Toxoplasmosis is a life-threatening opportunistic infection; many HIV positive and HIV negative women have evidence of past infection with Toxoplasma gondii
• Pregnant women who become acutely infected with Toxoplasma risk transmitting it to fetuses, which can result in malformation and death
• Physicians were advised to interpret results of FDA-approved IgM (immune globulin) anti-Toxoplasma antibody tests with caution, and should not rely on a single test result as the sole determinant in diagnosing recently acquired infection
• False positive IgM tests may lead a physician erroneously to believe a woman has been recently infected
• Learning of a "positive" test result, many women choose abortion to avoid risk of transmitting infection to the fetus. The FDA advisory describes an interim approach, usually requiring repeated blood testing to help differentiate recent from old infections (the latter carries a very low risk of transmitting toxoplasmosis to the fetus in HIV negative women).

Department of Health and Human Services. FDA public health advisory: limitations of toxoplasma IgM commercial test kits. July 25, 1997.

Liesenfeld O and others. Confirmatory serological testing results in remarkable decrease in unnecessary abortion among pregnant women in the United States with positive toxoplasma serology. IDSA. Abstract 31.

Wilson M and others. Evaluation of 6 commercial kits for detection of human IgM antibodies to Toxoplasma gondii. IDSA. Abstract 250.

Cancer-Causing HPV in Women with HIV

• Women with higher HIV viral loads (greater than 10,000 copes/mL) are more likely to have cancer-causing types of human papillomavirus (HPV) of the cervix than women with lower HIV viral loads
• Authors concluded that women with higher HIV viral loads may need more aggressive monitoring for the development of pre-cancerous cervical changes
• The study included 50 HIV positive women.

Luque AE and others. HIV-1 plasma RNA levels predict cervical infection with oncogenic human papillomaviruses (HPV). ICAAC. Abstract H-131.

AZT plus Immune Globulin during Pregnancy and Delivery Decreases HIV Transmission

• Pediatric AIDS Clinical Trials Group (ACTG) 185 recruited pregnant women with CD4 cell count less than or equal to 500 cells/mm³
• AZT plus either HIV immune globulin (HIVIG) or regular immune globulin (IVIG) was given
• HIVIG or IVIG for pregnant women was given monthly starting at 20-30 weeks of pregnancy and once to newborn within the first 24 hours after birth
• Standard AZT regimen was given during pregnancy, delivery and for newborn (as per ACTG study 076; see BETA, December 1996, pages 21-25)
• The overall perinatal transmission rate was 4.8%
• Transmission rate did not vary by type of immune globulin (HIVIG or IVIG)
• Transmission rate was higher in women with lower CD4 cell counts
• Transmission rate decreased in 1993 (9%) compared to 1996 (1.8%), but this was due to higher baseline CD4 cell counts in pregnant women
• Enrollment was halted due to projected inability to detect a difference in treatment effects.
• Mofenson L and others. Efficacy of zidovudine in reducing perinatal HIV-1 transmission in HIV-1-infected women with advanced disease. ICAAC. Abstract I-117.
• U.S. Public Health Service Guidelines Increasingly Followed for Reducing HIV Transmission to Newborns
• In 1996, 72% of newborns of HIV positive mothers were given AZT
• In 1996, 58% of HIV positive pregnant women took AZT during pregnancy
• In 1996, 87% of HIV positive pregnant women knew their HIV status before delivery.

Lindegren ML and others. Implementation of United States Public Health Service recommendations to prevent perinatal HIV transmission: pediatric HIV case surveillance, U.S. ICAAC. Abstract I-118.

CCR-5 Gene Mutation Confers Significant Protection Against Perinatal HIV Transmission

• Study looked at 582 children born to HIV positive mothers
• Newborns were 56% African-American, 30% Latino, 13% Caucasian and 1% other or mixed
• Overall HIV transmission rate was 27% (similar in each racial group)
• No HIV positive infant had 2 copies of the mutant CCR-5 gene (homozygous)
• 2 copies of the mutant gene were found in 2 HIV negative Latinos (1.7%) and 2 HIV negative Caucasians (3.8%), but no HIV negative African-Americans
• Authors concluded that the CCR-5 mutation protects newborns from HIV infection, similar to the high degree of protection against sexual transmission between gay/bisexual men
• Data suggested another potential avenue of therapy for preventing HIV transmission to newborns.

Philpott S and others. CCR-5 genotype and resistance to vertical transmission of HIV-1. ICAAC. Abstract I-119.

Peptidyl MIM D2A21 and TC4-08-PSS08 Effective against Gonorrhea and Trichomonas

• Peptidyl MIM D2A21 and TC4-08-PSS08 are new candidate vaginal microbicides
• Agents were effective in vitro against the organisms that cause gonorrhea and trichomoniasis
• Both infections were co-factors for increased HIV sexual transmission.

Coleman MS and others. In vitro activity of an antimicrobial peptide for use as a vaginal microbicide. ICAAC. Abstract F-44.

Cooper MD and others. Effects of contraceptive compounds on Chlamydia trachomatis and Neisseria gonorrheae. ICAAC. Abstract E-155.

Metronidazole for Vaginal Trichomoniasis

• New experimental once-daily oral metronidazole (Flagyl) formulation for Trichomonas vaginalis infection is as effective as standard 3-times-daily dosage.

Tutton C and others. Evaluation of a new once-a-day modified release formulation of metronidazole for the eradication of Trichomonas vaginalis. ICAAC. Abstract K-31 (see also K-34 and K-35).

Harvey S. Bartnof, MD, has been a member of the Scientific Advisory Committee of the San Francisco AIDS Foundation since 1987.