“We did not want to stay in our homes,” said Cassataro, a scientist at the National University of San Martin in the nation’s capital. “We wanted to use our knowledge to help in this pandemic.”

Determined to give Latin America its own protection from the fast-spreading virus, Cassataro’s team — 10 women and two men — quickly got to work. A government grant of $100,000 in May paid for initial studies, and human trials could start in about six months.

The U.S. and other superpowers have laid claim to billions of COVID vaccine doses that are nearing the finish line. That’s sparked worries that poorer countries will be left behind and shots will be slow to reach many of the world’s 7.8 billion people. Dozens of laboratories, researchers and companies from Thailand to Nigeria are bootstrapping their own work on inoculations.

Groups such as the World Health Organization, the Oslo-based Coalition for Epidemic Preparedness Innovations and Gavi, the Vaccine Alliance are working to ensure that coverage extends beyond the developed world. But memories of the 2009 swine flu outbreak, when pandemic vaccines barely made their way past the top tier of wealthy countries, persist.

“There’s a fear factor,” said Seth Berkley, Gavi’s chief executive officer.

Following the big drugmakers into the testing arena may be difficult, especially if an approved vaccine is available. But if the work fails to deliver a product to fight this pathogen, it may still give countries a leg up in future outbreaks.

Argentina’s vaccine is among roughly 170 advancing globally, according to the WHO. Airfinity, a U.K.-based analytics firm, has an even higher count — more than 280 — including about 50 in lower-income nations such as India, Turkey, Egypt and Kazakhstan.

The urgency is rising throughout the developing world. Argentina’s infections have surpassed 350,000 with the death toll climbing to more than 7,000. Neighboring Brazil has 3.6 million cases, while India’s have breached 3 million. With 600,000 infections, South Africa has become a fertile testing ground for vaccines.

One of the fastest-moving shots outside the wealthy world is in Thailand. Scientists at Chulalongkorn University plan to start human testing as early as September, relying on messenger RNA technology similar to that used by U.S. biotech company Moderna Inc. If successful, the Thai team aims to introduce a vaccine in the country by the second half of 2021.

Leapfrogging them all is Russia’s Sputnik V vaccine that President Vladimir Putin authorized before a conclusive test of its effectiveness and safety. The attention the inoculation has received — Russian officials have said at least 20 countries are interested in obtaining it — shows the level of desperation.

Latin America got some relief earlier this month when Argentina and Mexico reached agreements to produce as many as 250 million initial doses of AstraZeneca Plc’s experimental vaccine, an effort backed by billionaire Carlos Slim’s foundation. China has offered to loan Latin American and Caribbean countries $1 billion to purchase shots.

Yet it may take until the end of next year for the first 1 billion vaccine doses to be distributed throughout the world, according to Airfinity. And it’s not clear if the front-runners will gain approval, nor how effective they’ll be in various situations.

The swelling ranks of developers reflect those concerns, said Paul Offit, who runs the Vaccine Education Center at the Children’s Hospital of Philadelphia. A range of inoculations may be needed to protect different groups like the elderly, he said.

“I’m sure there’s a component of not wanting to be left out,” he said. “One doesn’t want to have to rely on the largess of other countries to protect their population. But I think the general interest among scientists in this world is that there’s going to be far more than one vaccine that will be in play.”

African countries don’t want to see a rerun of what happened when vaccines against rotavirus were introduced around 2006, according to Nigerian researcher Oladipo Kolawole. Early versions weren’t as effective there as in high-income regions, although subsequent shots have yielded positive results.

With coronavirus infections in Africa surpassing 1.1 million, Kolawole’s firm, Helix Biogen Consult, has begun collaborating with other Nigerian researchers on a vaccine. They plan to start animal tests soon and hope to have an impact beyond their country’s borders.

“We are not concerned about Nigeria alone,” Kolawole said. “We are concerned about Africa and the whole world.”

Many nations also face uncertainty over when doses will be available, how many they will be able to obtain and at what cost, according to Marie-Paule Kieny, a former WHO official who’s now a research director at Inserm, a French health-science institute. The crisis provides an opportunity to develop new technologies, skills and partnerships that could yield economic returns while also helping to respond to future health threats, she said.

“It’s always better when you have a problem to try to do something to resolve it yourself, not to stay there with empty hands,” she said.

Still, developing-nation researchers face a number of hurdles. The odds of success are lower in countries without existing vaccine industries, according to Kieny. While countries are keen to build up scant domestic manufacturing capacity, it’s a costly and complex business, and difficult to compete with larger producers, Gavi’s Berkley said.

Cassataro and her colleagues are developing a “subunit” vaccine that delivers harmless fragments of the virus — rather than the whole pathogen — to stimulate immunity. They’re considering two approaches, including one that could be delivered orally, and more funds would be needed to pay for human testing, she said.

The goal is to achieve “technological sovereignty” so Argentina won’t have to watch from afar as others vaccinate their way out of the pandemic.

“Waiting is very frustrating,” she said.