According to Johns Hopkins Bloomberg School of Public Health researchers, a new candidate vaccine against RSV has showed promise at fighting the disease.
Creating a vaccine with a live weakened virus – similar to what is used to prevent measles, mumps and rubella – requires a delicate balance: The virus must be weak enough so as not to make anyone sick and strong enough to induce a response from the body’s immune system.
The researchers, who conducted a clinical trial that is reported in the Nov. 4 Science Translational Medicine, say they have used the virus’ own machinery to create a vaccine that may protect young children from RSV disease. The vaccine, called MEDI ?M2-2, is made from a genetically engineered version of the virus that is missing the gene for the M2-2 protein, a protein that acts like a switch. When M2-2 is deleted, the virus produces more of the viral proteins that trigger immune responses but less of the infectious virus that makes people ill.
“An RSV vaccine with this M2-2 deletion could tip the balance toward a better immune response, which is what we predicted based on earlier laboratory studies,” says study leader Ruth A. Karron, MD, director of the Center for Immunization Research and a professor in the Department of International Health at the Bloomberg School. “From what we have seen in this small preliminary study in young children, this experimental vaccine is working as we hoped it would.”