First identified in 2012 in Saudi Arabia, Middle East Respiratory Syndrome (MERS) had the first outbreak outside of the Middle East this summer, when a businessman transported the virus to South Korea. Since then, it has infected 186 people, of which 36 have died. Now, researchers claim that they have developed an experimental MERS vaccine that showed promise in both mice and monkey models.
The scientists, from the National Institute of Allergy and Infectious Diseases' Vaccine Research Center, created the vaccine by analyzing the structural information of a particular protein – called the spike glycoprotein – that is found on the outside of the MERS virus and which it uses to enter cells when infecting the body. From this, they were able to develop a two-stage vaccine that primes the body. This new method of vaccine design, guided by an increased understanding of the virus’s structure and how it interacts with host cells, could possibly be used to develop one for human MERS.
The virus is thought to have originated in camels, where it has been found that predominantly younger animals host and shed the disease, which can be spread from close contact with the camels. The exact method of camel-to-human transmission is still unknown.
Once caught though, the symptoms range from fever, cough, shortness of breath, and acute respiratory disease like pneumonia. Transmission between people is not easy, but the death rate is considerably high at 36%.
The research, published in Nature Communications, was able to demonstrate that when mice had been given the experimental vaccine, they produced “broadly neutralizing” antibodies when later infected with the MERS virus. This means that the immune system was able to neutralize the biological effect that the virus has, rather than flagging the virus up to be destroyed by white blood cells.
In subsequent tests with rhesus macaque monkeys – who don’t quite react to MERS in the same way as humans – the researchers found that after being vaccinated, they were protected from severe lung damage when later infected.
This research comes just days after two suspected cases of MERS, which have now been proven to be a false alarm, shut down the Manchester Accident and Emergency unit in the U.K. At the same time, South Korean President Hwang Kyo-ahn has declared the country MERS-free after the country has not had any new infections for 23 days. But the World Health Organization is a little more reticent, and have said that they will not declare South Korea MERS-free until they have gone 28 days without infection, or twice the virus's incubation rate.