Researchers have created a needle-free measles vaccine, and the first clinical trials have shown that it triggers no adverse side effects in adult men.

The vaccination, developed by scientists at the University of Colorado at Boulder, in the US, is the first dry powdered vaccination ever put through Phase I clinical trials, and the method would greatly help to deliver the measles vaccine to developing countries, where clean needles aren't always accessible and it's difficult to safely store the liquid form.

It would also help encourage parents who are against putting their child through the discomfort of an injection to have them vaccinated.

Although a measles vaccine has been available for around 50 years, in 2013 the disease killed 145,700 people, most of them children, so it's important that researchers find more accessible ways to deliver the vaccine.

"Delivering vaccines in the conventional way, with needle injections, poses some serious challenges, especially in resource-poor parts of the world," said Robert Sievers, who was one of the leaders of the research, in a press release.

"[With this new method] you don't need to worry about needles; you don't need to worry about reconstituting vaccines with clean water; you don't need to worry about disposal of sharps waste or other vaccine wastage issues; and dry delivery is cheaper," said Sievers in the release.

The vaccine was tested in 60 adult men who were already immune to measles - either because they had been vaccinated or had already had the disease. This is because Phase I trials set out to assess the safety of a vaccine, rather than how effective it is. The vaccine was either delivered via two different types of inhalers, or regular injection, and the results have been published in Vaccine

The men in all three trials had similar reactions, with no clinically relevant side effects and some evidence of a positive immune response - even though that wasn't the purpose of the trial.

In preclinical trials, Sievers had already shown that the vaccine protected rhesus macaques and cotton rats from infection by the measles virus. They've also shown that the dry vaccine can safely be stored for six months to four years at room temperature or in refrigerators.

"Out of an abundance of caution, we test first in people who have already had the disease, or been injected earlier by needles with liquid vaccines," explained Sievers. "It is very good news that we encountered no problems, and now we can move on."

The next trial will assess the vaccine in adults and children who aren't immune to measles, and will help take this method of deliverly closer to a reality.

Source: EurekAlert