An experimental vaccine for the deadly MERS virus has shown positive results in animal testing, bringing researchers a step closer to a human vaccine regimen.
A two-step regimen of experimental vaccines against Middle East Respiratory Syndrome (MERS) prompted immune responses in mice and rhesus macaques, according to US National Institutes of Health scientists who designed the vaccines. Vaccinated mice produced broadly neutralising antibodies against multiple strains of the MERS coronavirus (MERS-CoV), while vaccinated macaques were protected from severe lung damage when later exposed to MERS-CoV. The findings suggest that the current approach, in which vaccine design is guided by an understanding of structure of viral components and their interactions with host cells, holds promise for developing a similar human MERS vaccine regimen.
Currently, no licensed vaccines are available for MERS, a disease that first appeared in 2012. The research team was led by Barney S Graham, Wing-Pui Kong, and colleagues at the National Institute of Allergy and Infectious Diseases’ Vaccine Research Centre.
The investigators used structural information about a viral protein called the spike (S) glycoprotein, which MERS-CoV uses to enter cells, to design a number of experimental vaccines that they administered to mice in a two-step regimen involving an initial ‘priming’ injection followed several weeks later by the same or a different ‘booster’ vaccine.