By Ara Sarafian, The Conversation
A new oral antiviral drug may be a future tool in the global fight against measles, according to a new international study.
The research, published today in the journal Science Translational Medicine, tested the new drug on ferrets infected with the canine distemper virus (CDV) – a virus with similarities to measles.
CDV is highly lethal to ferrets but all the animals treated with the new drug survived infection, remained disease free and developed robust immunity against the virus.
Although more research is needed before the drug is tested on humans, if successful it could help efforts to eradicate measles by reducing its spread during local outbreaks.
Not for human consumption, yet
In the future, the new oral antiviral drug could be used to treat people exposed to measles, such as family and friends of an infected person. This would help contain the overall spread of the virus.
Ian Barr, deputy director of the WHO Collaborating Centre for Reference and Research on Influenza, said while antiviral drug development was ongoing, a low percentage of the drugs actually made it to the market.
“Many of the antiviral drugs developed can successfully inhibit the virus but the side-effects profile is often the downfall,” Dr Barr said.
He added that, aside from determining the drug’s efficacy in humans against measles, researchers also needed to overcome the issue of resistance. Since viruses often mutate under drug pressure, antiviral drugs were always at risk of becoming ineffective.
Measles is back
According to the World Health Organisation (WHO) measles remains one of the leading causes of death among young children, despite the availability of a safe and effective vaccine. In 2012, approximately 122,000 people died from measles – the majority were children under the age of five.
The virus is highly contagious and spread through the air by breathing, coughing and sneezing. In a shared space with an infected person, 90% of people without immunity will catch it.
Because of this efficiency of infection, 95% of a population needs to be protected through immunisation to provide immunity to those who are not.
Lyn Gilbert, clinical professor in medicine and infectious diseases at The University of Sydney, said measles elimination has stalled recently even in Europe, North America and Australasia, where there are relatively high rates of vaccination.
In 2010, more than 30,000 cases of measles were reported across 32 European countries, where it had previously been considered to be controlled. This included 21 measles-related deaths. In 2011, the WHO reported more than 26,000 cases in 36 European countries and nine deaths.
Professor Gilbert said there were a number of reasons for the resurgence of measles, including:
reduced vaccination uptakehigh travel rates to countries where measles remains commonfears and misconceptions about the MMR vaccinemigrant children, from countries with low vaccine uptake, remaining susceptible in adolescence.
Michael Wise*, computational biology professor at The University of Western Australia, said the new drug wouldn’t affect vaccination rates in the developing world, where governments often couldn’t afford the vaccination let alone a “second-strike drug”.
“As for developed countries, it may give those disinclined to vaccinate a ‘reason’ to not do what they were minded not to do,” Professor Wise added.
Professor Gilbert said the main value of the drug would be for people who couldn’t be vaccinated for whatever reason.
“Programs to maintain high levels of vaccine uptake would need to continue to maintain protection against rubella and mumps as well as other childhood preventable diseases,” she added.
*Michael Wise is chair of the Immunisation Alliance of WA.