An experimental malaria vaccine protects a majority of adults against the mosquito-borne illness for up to one year, according to the results of a small study.

The findings also showed those who were vaccinated couldn’t spread the disease to others.

"These results are really important,” researcher Kirsten Lyke, from the University of Maryland School of Medicine in Baltimore, said in a university news release. "Malaria has such a devastating effect on children, especially in Africa. This vaccine has the potential to help travelers, military personnel and children in malaria-endemic areas.”

Hundreds of millions of people are infected with malaria and more than 500,000 die from the disease each year, the researchers noted. Most fatal cases of malaria involve children under the age of 5, the study authors said.

The first symptoms -- which can include fever, headache, chills and vomiting -- typically begin a week or two after being bitten by an infected mosquito, according to the World Health Organization. Without prompt treatment, malaria can progress to severe illness and death.

There is currently no malaria vaccine but this experimental vaccine, known as PfSPZ Vaccine, was developed and produced by Maryland-based Sanaria Inc. with support from the U.S. National Institute of Allergy and Infectious Diseases (NIAID). The researchers continue to test the vaccine in parts of Africa.

In this phase 1 clinical trial of the experimental vaccine, the researchers exposed a small group of 101 healthy adult volunteers to malaria in a controlled setting. None of the participants had ever had malaria before.

Of the group, 59 people were given the malaria vaccine, which contains a live but weakened form of the malaria parasite, Plasmodium falciparum.

Study participants who received the vaccine were divided into three groups, based on the following variables: the dose they received, how many immunizations they had, and how the vaccine was administered.

The remaining participants were not vaccinated.

The researchers assessed the effectiveness of the vaccine by analyzing the levels of the malaria parasite in blood samples taken from the participants.

The study authors added that receiving the vaccine through an IV provided better protection than injecting the vaccine into muscle.

The findings were reported May 9 in the journal Nature Medicine.

"In Africa, we’ve given up to 1.8 million parasites safely,” study author Dr. Robert Seder, from NIAID, told The New York Times. "As we keep going up in dose, the results get better.”

Long-lasting reliable protection from malaria is important for those routinely exposed to malaria, as well as travelers and those in the military, the researchers pointed out.