The nation’s top medical research agency has begun testing a Zika vaccine.

U.S. government researchers with the National Institutes of Health announced Wednesday that they have begun clinical trials. The study marks the group’s first attempt at a vaccine to fight the mosquito-borne disease.

There is currently no vaccine or treatment for Zika, which can cause severe brain-related birth defects if a mother is infected while pregnant.

The virus has mostly been reported in South America, Central America and the Caribbean, although officials announced last week that mosquitoes have apparently started spreading the disease on the U.S. mainland.

Zika prompts MTA plans for use of bug-killing larvicide

At least 15 people in Florida are feared to have been infected through mosquito bites.

Florida said it would make Zika testing available to all pregnant women at county health departments statewide at no cost.

Researchers are testing a Zika vaccine that could prevent infection.

 (FELIPE DANA/AP)

Federal health officials have taken the unprecedented step of directing pregnant women to avoid parts of Miami where people have tested positive for Zika.

Additionally, more than 1,650 cases of the disease have been reported across the U.S., nearly all the result of travel to a Zika-stricken country or sex with someone who was infected abroad.

Pregnant women warned to avoid Miami neighborhood as Zika spreads

“A safe and effective vaccine to prevent Zika virus infection and the devastating birth defects it causes is a public health imperative,” National Institute of Allergy and Infectious Diseases director Dr. Anthony Fauci said in a statement.

The vaccine trial will use at least 80 volunteers to test a drug intended to prevent infection.

U.S. vaccine maker Inovio Pharmaceuticals in June won U.S. Food and Drug Administration approval to begin testing its Zika vaccine on humans.

A Miami-Dade County mosquito control worker sprays around a home in the Wynwood area of Miami on Monday. At least 15 people in Florida may have been infected.

 (ALAN DIAZ/AP)

It began its clinical trial last month, aiming to enroll 40 healthy adult volunteers in Miami, Philadelphia and Quebec City.

But funding for the preventative measure could become an issue moving forward.

President Obama in February asked the Republican-led Congress for about $1.9 billion in emergency funds to combat the disease domestically and abroad, but lawmakers have so far not passed funding legislation.

A $1.1 billion compromise failed after Republicans in the House of Representatives attached language that would place restrictions on abortion and defund part of Obama’s signature 2010 health care law.

With News Wire Services