Scientists have developed a vaccine that can protect animals from Middle East Respiratory Syndrome (MERS).
The announcement comes from researchers at the Perelman School of Medicine at the University of Pennsylvania. The findings are published in Science Translational Medicine.
News of the vaccine follows reports of more MERS cases in the Middle East. Saudi Arabia's Ministry of Health confirmed 22 new cases from August 17 to August 19.
MERS is a serious respiratory illness caused by a virus (Middle East Respiratory Syndrome Coronavirus, or MERS-CoV). The virus can be transmitted from animals to humans. It can also spread from person to person.
According to the World Health Organization (WHO), about 36 percent of people known to have MERS have died.
Monkeys Became Fully Protected
The researchers administered their synthetic DNA vaccine to rhesus macaques monkeys.
Six weeks later, they exposed the monkeys to the MERS virus. Tests showed the monkeys were fully protected from the disease.
In the Middle East, one route of viral transmission is camel to human. The vaccine triggered antibodies linked with protection in camels. That means it could break that link in transmission.
David B. Weiner, Ph.D., a professor of pathology and laboratory medicine at Perelman, led the research. In an interview with Healthline, Weiner said the vaccine also helps control the spread of disease in other ways.
In a recent outbreak in South Korea, certain people spread the virus to a high number of others. Weiner theorizes that vaccinating those “super spreaders” could limit their ability to spread the virus to others.
It could also cut down on person-to-person transmission among healthcare workers.
Weiner said there’s still a lot of work to be done. He expects clinical trials in humans to begin this year.
“The significant recent increase in MERS cases, coupled with the lack of effective antiviral therapies or vaccines to treat or prevent this infection, have raised significant concern,” Weiner said in a press release. “Accordingly, the development of a vaccine for MERS remains a high priority.”
What Is MERS and How Does It Spread?
MERS is a viral disease that affects the respiratory system. Symptoms of MERS include cough, shortness of breath, and fever. Diarrhea and vomiting are less common symptoms. Serious complications may include pneumonia and kidney failure.
The risk of complications or death is higher if you have a weakened immune system or other health problems.
MERS was first identified in Saudi Arabia in 2012. Since then, it has been reported in countries outside the Middle East.
There have been 1,413 confirmed cases of MERS worldwide, Scott J. N. McNabb, Ph.D., M.S., research professor at Emory University, Rollins School of Public Health, told Healthline. The disease is blamed for 502 deaths since September 2012.
This year, a large outbreak occurred in the Republic of Korea. According to the WHO, at least 186 people were confirmed to have MERS. Thirty-six people died.
How the virus spreads from animals to people isn’t clear.
The virus spreads from person to person only with close contact. MERS can spread quickly in a hospital setting. Doctors and nurses who provide unprotected care to patients with MERS are at high risk.
The incubation period can be anywhere from two to 14 days. Most people have symptoms within five or six days.
Right now, there’s no vaccine or specific treatment for MERS.
In the United States, there’s little risk to the general public, according to the Centers for Disease Control and Prevention (CDC). McNabb said there have been two reported cases. He noted both involved health professionals who contracted the disease in Saudi Arabia.
“While the importation of the virus is of concern,” said McNabb, “once physicians know what they’re dealing with, it is containable and easy to prevent transmission. The majority of U.S. healthcare professionals are trained to take a travel history and are made aware of emerging threats around the world as well as isolation protocol should a person fit case definitions.”
Questions Remain, but Efforts to Stop MERS Continue
“The global community suffers from a lack of clear understanding of the disease and very poor coordination between global prevention, detection, and response activities,” said McNabb.
He explained that the WHO International Health Regulations Committee maintains that MERS isn’t a public health emergency of international concern.
“The virus doesn’t exhibit sustained person-to-person transmission — like typically seen with influenza — and there is no evidence to suggest that the virus has mutated,” added McNabb.
The virus tends to spread when people are in close quarters.
“With the upcoming Hajj and Umrah season,” said McNabb, “an estimated 2 million-plus people descend onto the cities of Mecca and Medina, living in close quarters. Concluding their religious obligations, they return to their homes around the world.”
Previous mass gatherings have not resulted in the spread of MERS. McNabb credits the Saudi Arabia Ministry of Health. He cautioned that it’s still a risk that requires continued vigilance. And proper training and quarantine procedures need to be instituted early in an outbreak, he said.
“Basic questions regarding reservoir populations and transmission to humans remain unanswered, weakening prevention activities,” said McNabb.
He said other unknowns include natural history, risk factors, pathogenesis, viral virulence, viral kinetics, duration of infectiousness, protective immune responses, optimum management, and prognostic factors.
“The vaccine could be very effective and the signs are hopeful,” said McNabb.