When MERS-CoV emerged in 2012, NIAID scientists and grantees mobilized quickly to research the virus. Key areas of investigation include basic research on where MERS-CoV comes from and how it causes disease, the development of animal models to study the virus, and the development of treatments and vaccines.
To this end, NIAID hosted a one-day meeting for scientists researching MERS-CoV in June 2013. Discussion focused on the basic and clinical data needed to develop therapeutics and vaccines, lessons learned from the 2003 outbreak of severe acute respiratory syndrome (SARS), and recommendations for next steps. A report (PDF) of the meeting, outlining the current state of the science and research goals, was released in September 2013.
NIAID also leads an interagency working group on MERS-CoV therapeutics. Other federal government agencies represented include the Centers for Disease Control and Prevention, the Food and Drug Administration, the U.S. Department of Defense, and the Biomedical Advanced Research and Development Authority.
To develop effective therapeutics and vaccines against MERS-CoV, scientists must first understand how the virus survives, infects, and causes disease in people. This knowledge is gained by first studying the virus in tissue culture and then developing animal models that mimic human disease. After studies showed that MERS-CoV does not cause disease in standard mice or hamsters, scientists at NIAID’s Rocky Mountain Laboratories (RML) took the unusual step of moving directly to developing a large-animal model because of the public health implications posed by MERS.
Their model of MERS-CoV infection in rhesus macaques shows that clinical signs of disease appear within 24 hours of infection, and the virus causes disease deep within the lungs, leading to pneumonia. The RML team is using the model to study how MERS-CoV causes disease and to evaluate potential vaccines and treatments. Meanwhile, scientists at NIAID and elsewhere continue to try to develop a small-animal study model in rodents, which are simpler to use and less expensive than macaques.
Coronaviruses evolve quickly and have a long history of shifting between animal species, leading scientists to explore where MERS-CoV comes from and how people become infected. Thus far, evidence suggests that the virus can be transmitted from person to person but only between people in close contact with one another, such as family members or patients being treated in clinical settings.
Researchers also are investigating whether people are becoming infected through contact with an animal, such as a bat, that acts as a reservoir or carrier for the virus. There also is anecdotal evidence of MERS-CoV patients’ exposure to camels prior to illness. In September 2013, scientists supported by NIAID’s Centers of Excellence for Influenza Research and Surveillance developed a laboratory test to detect antibodies to a key MERS-CoV protein based on a form of HIV that cannot cause illness. They used this assay to test for MERS antibodies in dromedary camels, water buffalo, pigs, cows, sheep, and goats in Egypt. More than 90 percent of camels tested positive for these antibodies, while all of the other animals tested negative, suggesting that MERS-CoV or a related virus had infected dromedary camels.
NIAID-funded researchers at the University of Washington are searching for MERS-CoV therapeutics by analyzing which human genes are significantly disrupted in the early and late stages of infection. This information will help scientists to predict which classes of drugs may be able to stop the virus or the genetic disruptions it causes during infection. Their findings, published in April 2013, show that severe acute respiratory syndrome (SARS)-CoV and MERS-CoV affect human cells differently. In general, MERS-CoV disrupts more genes more profoundly and at more time points after infection than SARS-CoV.
RML scientists studying MERS-CoV found that a combination of two licensed antiviral drugs, ribavirin and interferon-alpha 2b, can prevent the virus from reproducing in laboratory-grown monkey cells. They subsequently demonstrated in a monkey disease model that the combination of antivirals reduces MERS-CoV replication and improves clinical outcome. Ribavirin and interferon-alpha 2b are routinely used to treat viral infections such as hepatitis C.
Scientists have learned that for MERS-CoV to infect a person, the virus enters cells using a protein known as the spike, or S, protein. After entering the cell, the virus delays the normal immune system response, allowing the infection to gain a foothold in the body. By the time the immune system recovers, the infection has progressed and become much harder to fight off. NIAID-funded scientists are exploring MERS-CoV vaccines that would block the S protein or the delay of the immune system.
In August 2013, NIAID awarded two contracts to advance research into new treatments and vaccines for MERS-CoV through its Animal Models of Infectious Disease program. Under these contracts, NIAID-supported scientists will develop a mouse model of MERS-CoV infection, which will then be used to evaluate promising new treatments and vaccines against the virus.
Last Updated October 28, 2013
Last Reviewed October 28, 2013