Babies born to Zika-infected mothers are highly likely to have brain damage, even in the absence of obvious abnormalities like small heads, and the virus may go on replicating in their brains well after birth, according to three studies published Tuesday.

Many types of brain damage were seen in the studies, including dead spots and empty spaces in the brain, cataracts and congenital deafness.

There were, however, large differences among these studies in how likely it was that a child would be hurt by the infection.

One study, published by The Journal of the American Medical Association, assessed 442 pregnancies registered with the Centers for Disease Control and Prevention between January and September in the continental United States and Hawaii, most of them in returning travelers.