What Can the “Mississippi Baby” Teach Us About HIV?
Researchers are hoping to achieve long-term remission for newborns infected with HIV with the start of a new NIH-funded clinical trial, as announced earlier this week. An international expert in pediatric HIV infection and transmission, Grace Aldrovandi, MD, CM, Chief of the Division of Infectious Diseases at Children’s Hospital Los Angeles (CHLA), answers a few questions about HIV in infants.
How can HIV appear dormant—as in the case of the “Mississippi Baby”?
HIV is usually not dormant. It is an active infection. The case of the “Mississippi Baby” is highly unusual.
When HIV infects our cells (mostly T-cells, which are part of our immune system), it changes its viral RNA to DNA. Then, the HIV-DNA inserts into our human DNA. The HIV medicines stop the virus itself from replicating, but do not get rid of the HIV-DNA incorporated into the T cells. Usually, if the medicines are stopped, HIV can be detected in the blood within one to two weeks. The “Mississippi Baby” is so unusual because her virus did not rebound for almost two years, therefore appearing “dormant”.
How did the “Mississippi Baby” acquire HIV in the first place?
Infants can get infected with HIV from their mothers at three different times: while in the womb, during delivery or through breast milk. Once infection is established, it is life-long. Approximately 40% of babies will be infected from their mother without prevention.
This rate of transmission drops to 1 to 2 percent in the U.S. and other developed nations, by giving the mother HIV medicines during pregnancy and delivery and the infant HIV medicines for a short period after birth. While more HIV medicines are being used in developing nations and, importantly, being used during breastfeeding (babies in the U.S. currently receive formula), transmission rates are finally starting to decrease.
Are the symptoms and outlook different in children with HIV compared to adults?
Without treatment, most babies do very poorly with HIV infection—much worse than adults. The infection progresses rapidly with high levels of circulating virus, and more than 50% of infants die in the first one to two years of life. With the great advances in treatment, infants with access to treatment can do quite well. Although infected infants will have some metabolic consequences of their infection, most can live into adulthood with a good quality of life and life expectancy.
Can a child truly be cured of HIV?
We are not sure yet, but we are working on it. In my lab at CHLA, we are trying to understand early infection and find out how soon treatment needs to be started to prevent the long-living T-cells from being infected. It appears to be less than a week after infection. Second, HIV scientists are trying to figure out how to stimulate those long-lived cells so that they can be purged from the body.
So, while we can prevent infection from mother to baby quite well, we cannot yet cure a baby of HIV, but we remain very hopeful with the incredible advances to date.
What will this new NIH trial bring to the knowledge of HIV transmission and treatment in infants?
The new NIH-sponsored clinical trial aims to replicate the treatment of the “Mississippi Baby” in other infants infected with HIV in the womb. The hope is that other infants can experience the same benefits as the “Mississippi Baby”, specifically in the depletion of viral reservoirs. These reservoirs are locations, such as cells or tissues, which “hide” HIV from antiviral medications, and may lead to life-long HIV infection. If the size of these reservoirs can be decreased, other infants may potentially be able to stop treatment for extended periods of time, without an immediate rebound of HIV.