U.S. progressing toward Zika vaccine

U.S. health officials have taken the next step for an experimental vaccine to protect against Zika, the mosquito-borne virus that can cause devastating birth defects in pregnant women.

The National Institutes of Health announced March 31 that the agency has begun enrolling volunteers for critical next-stage testing of an experimental DNA vaccine.

This is a totally new kind of vaccine. Traditionally, vaccines are made using a dead or weakened virus to train the body’s immune system to recognize and fight that infection.

In contrast, the new Zika vaccine relies on DNA. It is made with a circular piece of DNA carrying genes from the Zika virus that, once in the body, produce particles that resemble Zika. These particles are close enough to alert the immune system, but they cannot cause infection.

The NIH also is testing more traditional Zika vaccine candidates, but the easier-to-make DNA vaccine is the first ready to advance to this second stage of testing.

The first volunteer was vaccinated March 29 in Houston. The NIH is gearing up for a two-part study of thousands of people in the U.S. and Brazil, Mexico, Panama, Costa Rica and Peru.

Zika has caused an epidemic in parts of Latin America and the Caribbean, and continues to spread to other countries. Mosquito season is fast approaching the northern hemisphere — and the risk persists internationally.

“It is imperative that public health research continue to work to contain the spread of the virus,” Anthony Fauci, director of NIH’s National Institute of Allergy and Infectious Diseases, said March 31.

Fauci said researchers may have clues by early 2018 about how well the vaccine works.