The study was conducted by researchers at Edinburgh University who analyzed thousands of genes in order to find out why herpes simplex virus type 1, which infects more than 90 percent of adults, causes cold sores only in a quarter of those infected. The researchers discovered a gene that is responsible for the production of a protein called Interferon-lambda which can prevent HSV-1 from being reactivated.
On comparing the DNA of people who regularly suffer from cold sores with that of people who are infected with HSV-1 but are not troubled much, the researchers found that the gene that produced Interferon-lambda was flawed in those who often got cold sores.
"Most people carry the cold sore strain of the herpes simplex virus but until now we never knew why only some of them develop cold sores. Knowing that susceptibility to the virus involved relates to people's genes reinforces the need to research, not only the evolution of the viruses themselves, but the susceptibility of the hosts to infection", lead researcher Professor Juergen Haas said.