WASHINGTON, April 16 (Xinhua) -- A novel oral drug may protect unvaccinated people who are exposed to measles from getting sick and prevent them from spreading the virus to others, an international team of researchers said Wednesday.
Like the flu, measles spreads through the air by breathing, coughing or sneezing. There is typically a two-week window between becoming infected with the virus and the onset of symptoms like skin rash, runny nose and fever.
The novel drug, termed ERDRP-0519, is specifically designed to work during this two-week window, when vaccination can no longer protect from disease.
"This post-exposure therapy application determines the desired characteristics of the drug, which are: orally available, cost- effective manufacture and ideally, high shelf stability," corresponding author Richard Klemperer, professor of Georgia State University, told reporters at a press telebriefing.
"With these criteria in mind, we have developed over the past years a small molecule drug that blocks the measles virus RNA polymerase enzyme, which is essential for replication of the virus. "
The researchers tested the drug in ferrets infected with canine distemper virus, which is a close relative of measles virus.
They found that all of the infected ferrets treated with the drug survived the lethal infection, showed no clinical signs of disease and developed a robust protective immune response.
The drug could be used to treat friends, family and other social contacts of a person infected with measles virus, who have not developed symptoms yet but are at risk of having caught the disease, Plemper said.
"The emergence of strong antiviral immunity in treated animals is particularly encouraging, since it suggests that the drug may not only save an infected individual from disease but contribute to closing measles immunity gaps in a population," Plemper said.
The researchers emphasized the drug is not intended as a substitute for vaccination, but as an additional weapon in a concerted effort to eliminate the measles. They planned to test the drug's safety and efficacy in larger animals, before moving into clinical trials in humans.
"If our next series of studies confirms that the human situation mirrors what we have seen in ferrets, then this drug may make a major contribution to measles eradication by suppressing local outbreaks, and helping to close the existing gaps in population immunity," Plemper said.
Despite the existence of an effective vaccine, annual measles deaths worldwide have remained constant at around 150,000 since 2007, without further progress toward the eradication goal.
The reasons for this are the highly infectious nature of the virus and insufficient vaccine coverage, in the developing world largely due to issues of access and resources, and in many developed countries in particular in the European region due to parental concerns regarding vaccination safety.
The study, which also involved researchers from the Emory Institute for Drug Development and the Paul-Ehrlich Institute in Germany, was published in the U.S. journal Science Translational Medicine.