Bloodborne HIV: Don't Get Stuck!

During 1997–2000, the Zimbabwe Vitamin A for Mothers and Babies (ZVITAMBO) study enrolled 14,110 women-baby pairs within 4 days after delivery. Tests at delivery found that 4,495 (32% of 14,110) mothers were HIV-positive.  The study followed mother-baby pairs for up to two years, taking blood from babies just after delivery, 6 weeks, 3 months, 6 months, and — if the baby’s mother was HIV-positive at delivery — every subsequent 3 months for up to 2 years.[1]

Most mothers who were HIV-positive didn’t know it, and so didn’t know they were at risk to infect their babies through breastfeeding. As project staff explained: “Mothers could learn their [HIV test] results at any time during the study.., but they were not required to do so. This feature makes ZVITAMBO unique. All other studies of infant feeding and HIV have been conducted among mothers who knew their HIV status.”[page 951 in reference 3] Only 7.2% of mothers asked for their results by 3 months after delivery (HIV-negative mothers were more likely to ask). Through the end of the project, only 15.5% heard the results of their tests.[2]

If mothers learned they were HIV-positive, the study advised them to exclusively breastfeed for 6 months, then stop.[2] But if mothers didn’t know, the study did not tell them their child was at risk. Children of HIV-positive mothers continued to breastfeed: 97% were breastfeeding at 6 months, 92% at 12 months, 66% at 18 months, and 19% at two years.[1] The study found that 141 babies of women who were HIV-positive at delivery got HIV from 6-24 months after delivery,[3] presumably from breastfeeding (a few might have gotten HIV from skin-piercing events, but the study says nothing about that).

Note: If the mother tested HIV-positive at delivery, the study took blood samples from babies every 3 months, but the study did not test a baby’s blood for HIV until after that  baby’s last visit. If the baby was infected at his or her last visit, the study went back to test previous samples to see when the baby got HIV.[1]

The object of the research was to see if large doses of vitamin A given to some mothers and infants shortly after delivery — but not to others — would reduce mother-to-child HIV transmission, improve child survival, and protect women from new HIV infections. It didn’t. If anything, large doses of vitamin A slightly to modestly increased risks for mother-to-child HIV transmission, child death, and mothers’ risk to get HIV over 1-2 years (the observed increases were small and may have been statistical accidents).[1,4]

The research was funded by: the Canadian International Development Agency; USAID; Bill and Melinda Gates Foundation; Rockefeller Foundation; BASF (Ludwigshafen, Germany).[1]

References

1. Humphrey JH, Iliff PJ, Marinda ET, et al. Effects of a single large dose of
vitamin A, given duringthe postpartum period to HIV-positive women and
their infants, on child HIV infection, HIV-free survival, and mortality. J Infect
Dis 2006;193:860–71. Available at: https://academic.oup.com/jid/article/193/6/860/1032189 (accessed 4 November 2018).

2. Piwoz EG, Iliff PJ, Tavengwa N, et al. An education and counseling program
for preventing breast-feeding-associated HIV transmission in Zimbabwe:
design and impact on maternal knowledge and behavior. J Nutr
2005;135:950–5. Available at: https://academic.oup.com/jn/article/135/4/950/4663805 (accessed 4 November 2018).

3. Humphrey JH, Marinda E, Mutasa K, et al. Mother to child transmission of HIV among Zimbabwean women who seroconverted postnatally: prospective cohort study. BMJ 2010; 341: c6580. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3007097/ (accessed 4 November 2018).

4. Humphrey JH, Hargrove JW, Malaba LC, et al. HIV incidence among post-partum women in Zimbabwe: risk factors and the effect of vitamin A supplementation. AIDS 2006; 20: 1437-1446. Abstract available at: https://www.ncbi.nlm.nih.gov/pubmed/16791019 (accessed 4 November 2018).