Donated breast milk, arranged on social media, and five exposed infants

HIV can be transmitted through breast milk. For mothers on antiretroviral
therapy with a sustained undetectable viral load the risk is very low, and
under the US Department of Health and Human Services Perinatal HIV Clinical
Guidelines, **mothers with an HIV viral load above 50 copies/mL are
recommended not to breastfeed**. Exposed children are recommended for HIV
testing immediately after the last exposure, and again at **14–21 days,
4–6 weeks, and 4–6 months** after breastfeeding stops.

What happened

On 17 October 2025, the County of Santa Clara Public Health Department was
notified of a woman 15 weeks and 4 days pregnant who had received a
positive HIV test at her prenatal screening on 10 October.

She was **breastfeeding her two-year-old daughter and donating breast milk
through two social media groups**.

The department investigated and identified five possibly exposed infants.
Their parents were encouraged to have them tested, and to obtain donated
breast milk only from accredited milk banks.

**No evidence of HIV transmission through the donated breast milk was
identified.**

The part that was hard

The investigation ran through social media groups, and investigators
found that genuinely difficult — tracing who received milk, in what quantity
and when, across informal groups that keep no records and have no obligation
to cooperate.

That is the finding with consequences beyond this case. A milk bank has a
donor register and a recipient list; a social media group has neither, so a
single positive test cannot be traced to a known set of exposures.

What the report recommends

• Patient and public education about the risks of informal breast milk
  sharing through unregulated means, and about the availability of
  accredited milk banks
• Training for disease investigators in conducting investigations using
  official profiles in social media groups

Both recommendations exist because the failure here was not medical. Nobody
was infected. What nearly went wrong was the ability to find out.

*Source: Løchen A, Pang D, Howard S, et al. Notes from the Field: Potential
Infant HIV Exposure from Donated Breast Milk Received Through Social Media —
Santa Clara County, California, May 2025–January 2026. MMWR, Centers for
Disease Control and Prevention.*