Sounds crazy? Don’t be too quick to judge.

A number of labs across the country are looking into different ways to develop a vaccine out of concern that the virus might be linked to the birth defect called microcephaly, in which babies are born with small heads.

The Vaccine Research Center at the National Institute of Allergy and Infectious Diseases (NIAID) in Maryland is currently working on one such vaccine, but it is far from the point at which it will be tested on humans.

"Most vaccine development efforts are measured in decades," Dr. Barney Graham, deputy director of the NIAID center, told NPR. "Almost every vaccine we have for a viral disease has come several decades after the discovery of the virus."

That was the case with Ebola, which saw a vaccine that was poised to go into a large study in humans late in the 2014-15 outbreak in West Africa that killed more than 11,000 people.

Zika infections have been confirmed in nine pregnant women in the United States; all contracted the virus overseas. Three of the babies have been born, one of them with microcephaly.

The Centers for Disease Control and Prevention said Friday that it is also investigating 10 additional reports of pregnant travelers with Zika.

The Zika virus — spread mainly by mosquito bites — is epidemic in Latin America and the Caribbean. The virus causes mild illness or no symptoms in most people.

Since August, the CDC said it has tested 257 pregnant women for Zika; eight were positive and a state lab confirmed a ninth.

Two pregnancies ended in miscarriage, but it's not clear if the Zika infection was the cause. Two women had abortions. Two are continuing without reported complications.