A trial of a Middle East respiratory syndrome (Mers) vaccine that targets the coronavirus that causes the disease in Arabian camels has delivered some encouraging early results, scientists say. The vaccine, developed by a team led by Bart Haagmans at the Erasmus Medical Centre in Rotterdam, was found to "significantly" lower the level of virus in camels and protect them from Mers symptoms.
Researchers say it could serve as a pre-emptive measure to reduce the spread of the pathogen from camels to humans. Since the first human case of Mers was reported in Saudi Arabia in 2012, the virus has infected more than 1,200 people in the Middle East and killed more than 500 of them.
While the spread of the virus among humans is limited at present, scientists fear it could mutate and cause a global pandemic if left unchecked. "The best strategy is trying to suppress circulation of the virus in camels," Christian Drosten, a virologist at the University of Bonn in Germany, told the journal Science.
In their trial, Haagmans's team genetically altered a smallpox vaccine to carry a Mers virus protein on its surface. They then administered the vaccine both nasally and intramuscularly to Arabian camels, and found that they developed detectable levels of antibodies against the Mers coronavirus within three weeks.
The level of protection to the pathogen in vaccinated camels correlated with the levels of antibodies in their system. While the early results are promising, scientists are unsure if the vaccine offers long-lasting protection against the virus.
Meanwhile, a separate study found the Mers virus was prevalent in 12% of a sample of 1,300 camels examined in Saudi Arabia, the country most affected by the pathogen, between May 2014 and April 2015.
Genetic sequencing revealed there were five different lineages of the Mers coronavirus, all of which contained both human and camel virus sequences, indicating there is a low threshold for interspecies transmission.
Scientists warned that more strains of the Mers virus may emerge in the future and added that preventing its transmission from animals to humans is likely to be the best way to contain its threat.