“The problem with most vaccines is that their effectiveness is often short-lived,” said the study’s lead author, Klaus Früh, Ph.D., of OHSU’s Vaccine & Gene Therapy Institute and a professor of molecular and cellular biosciences at the OHSU School of Medicine. “Our cytomegalovirus-based vaccine platform can create and keep immunity for life. With further research and development, it could offer a lifetime of protection against malaria.”
Malaria is a serious and sometimes fatal disease caused by Plasmodium parasites, which are spread to humans through mosquito bites. It can cause high fevers, shaking chills, flu-like illness and, in the worst cases, death. Worldwide, 216 million people were infected with malaria in 2016, leading to 445,000 deaths. The vast majority of infections occur in Africa.
The decades-long search for an effective malaria vaccine has been challenging. The World Health Organization is using one vaccine—known as RTS,S/AS01 or by its brand name, Mosquirix—as part of new, routine vaccination programs in three African countries. But RTS,S has been shown to only reduce malaria transmission in kids—in whom malaria is most often fatal—by 39 percent four years after it was administered. Its efficacy was further reduced to 4.4 percent seven years afterward. Vaccines against viruses and bacteria typically have protection rates of more than 90 percent.
Most vaccines are designed to encourage the human body to respond to invading, disease-causing pathogens by creating antibodies that disable those pathogens. OHSU’s new vaccine takes a different approach by using a weakened form of a common herpes virus—cytomegalovirus, or CMV—that infects most people without causing disease.