Congenital measles is no longer rare in outbreak counties

Congenital measles means a newborn is infected because the pregnant parent had measles in the days before delivery. On 8 September 2026 the American Academy of Pediatrics published a Red Book FAQ for this presentation.

Background

AAP estimates that about 25 to 30 percent of infants born to mothers who contract measles in the days just before delivery may also become infected. Outcomes run from no symptoms to rash, multi-organ disease, or death.

CDC, updated 25 September with cases through 24 September, lists 3,659 confirmed U.S. cases. About 95 percent were unvaccinated or of unknown status. Children under 5 are 656 cases, and 14 percent of that age group was hospitalized. Pennsylvania accounts for 850 of the 2026 cases on the CDC table, against 16 in 2025. South Carolina is at 670. Forty new outbreaks are reported, and 95 percent of cases are outbreak-associated. CDC lists 2 deaths and says the count can change. State reports have described more measles-associated deaths.

What changed

The FAQ covers definition, newborn presentation, testing, isolation, follow-up, and prevention in pregnancy. MMR is still two doses, usually from 12 months. An early dose at 6 to 11 months in an outbreak does not count as the first routine dose. AAP and CDC still cite about 97 percent effectiveness after two doses. They split on the rest of the schedule: in January the federal schedule moved flu and COVID-19 off routine recommendation. AAP kept a routine schedule and no longer endorses the CDC childhood schedule.

Competing viewpoints

AAP treats 2026 as an elimination-era failure and wants immunity checked before delivery. The revised federal schedule treats several vaccines as shared decision-making. Measles remains on both. On congenital disease, AAP says expert opinion fills thin evidence. Death attribution is still being standardized. The risk to a newborn exposed late in pregnancy is real, and the national death tally is not finished.

What to do

If you are pregnant and unsure of immunity, ask for the record or a titer before the third trimester. MMR is not given during pregnancy. If you give birth in an outbreak county after a fever and rash in the prior two weeks, tell the nursery and ask about isolation, testing, and immune globulin. Infants 6 to 11 months in outbreak areas can ask about an early dose, then still get the routine series. This is not medical advice. Sources: AAP news release 8 September 2026, Red Book Online, CDC measles page updated 25 September 2026.