STORRS, Conn. — As a virus called Zika rampaged across his native Brazil last fall, Paulo H. Verardi followed along in the Brazilian newspapers he reads online in his University of Connecticut office. With growing astonishment, he learned that the little-known virus had been linked to a rare and devastating birth defect: babies born with malformed heads and underdeveloped brains.

Verardi, a vaccine researcher, sensed something big was happening — weeks before the US media paid any attention. He had just finished devising a method that could speed an early stage of vaccine development. He needed to test his method on a virus. And he knew the world needed to stop Zika.

That’s how the 48-year-old biologist became one of the first US researchers — possibly the very first — to start working on a Zika vaccine.

Now that the World Health Organization has declared an international health emergency over Zika, and President Obama has asked Congress for $1.8 billion to fight it, the big guns have entered the race to develop a vaccine, a process likely to take years. Verardi, a member of UConn’s Center of Excellence for Vaccine Research, said two vaccine makers in Connecticut have contacted him seeking to collaborate.

He also got a call from Brazil’s consul general in Hartford, Fernando de Mello Barreto, who heard Verardi interviewed on the local public radio station. Barreto offered his help.

Verardi has no illusions about coming up with the winning formula. “In the vaccine field, things usually don’t work,’’ he said matter-of-factly. But he added: “Even from the ones that don’t work, we learn a lot.’’ Maybe, he said, his success — or failure — with the early stages of vaccine development will contribute to the global effort.

When the world was caught off guard by the Ebola outbreak in 2014, researchers and public health specialists warned that other infections could emerge from anywhere, unpredictably.

Zika fulfilled that prophecy, although it is not deadly like Ebola. No one foresaw that a mosquito-borne virus in Africa and the South Pacific, never before known to cause serious illness, would show up in the Western Hemisphere and quickly stir international alarms.

Zika’s novelty adds to the challenge of developing a vaccine.

Until recently, few had given much though to Zika, because most infected people don’t get sick and the rest of them recover. As a result, said Dr. Dan H. Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, very little is known about the virus.

Sanofi Pasteur, a major vaccine maker, recently made an inoculation against dengue, a Zika cousin, and plans to use that experience as a platform to develop a Zika vaccine. But there’s no guarantee.

“It is a different virus so it needs to be a different vaccine,’’ Barouch said. “One thing that we’ve learned — it’s difficult to predict with confidence how easy or difficult it will be, or how long it will take. . . . Vaccine development is often not a straight linear pathway from point A to point B.’’

Verardi became interested in developing vaccines as an undergraduate studying biology in Brazil, when he helped vaccinate people against polio. Traveling into some of the poorest sections of his country, he was moved by the potential of vaccines to improve and save lives. “It felt so good and right to do that,’’ he said. “It protected them from this terrible disease.’’

He enrolled at the University of California Davis to study the biological underpinnings of viral infections. There, he earned a PhD, did postdoctoral research, and served as a research professor. Seven years ago, he came to UConn. His work has contributed to the development of animal vaccines and to improving the safety and efficacy of human vaccines.

His is a small operation. A virology lab at, say, Harvard might be populated by a dozen or more graduate and postdoctoral students. The Verardi Laboratory consists of himself, three graduate students, and two undergrads.

But small enterprises can yield fruitful things. A study in the February issue of the journal Health Affairs found that most of the early stage research in vaccine development emerged from small and medium-size companies.

“If we want to try to get this Zika virus vaccine . . . ’’ said one of the study authors, Dr. Aaron S. Kesselheim of Harvard Medical School and Brigham and Women’s Hospital, “what we’re going to want to do is devote more resources and attention to those kinds of innovation centers.’’

A vaccine works by priming the immune system to fight off a specific infection. Verardi is designing a genetically altered virus that won’t make a person sick, but will induce an immune response.

He and his students are splicing fragments of Zika genes into a harmless virus known to be effective in stimulating the immune system. They are employing a technique Verardi developed — but has not yet published — that can create the prospective vaccine in a week, compressing a process that normally takes months. So, he said, he can generate many variations quickly.

His team is testing to see which Zika fragments are most likely to work, based on the reactions of cells in laboratory dishes. If their vaccine candidate looks effective in the lab, they will need more money to take it to the next level — testing to see if it produces an immune response in mice.

UConn has been supporting Verardi’s research so far, and he is seeking money from the National Institutes of Health. If his approach proves successful, he will need to partner with a biotech company able to manufacture the vaccine and test it in humans.

But in the end, Verardi may merely contribute knowledge to speed the development of someone else’s vaccine. “Everybody working together solves a different little piece of the puzzle,’’ Verardi said.

Felice J. Freyer can be reached at felice.freyer@globe.com.