PATH and our partners intensify attack on Japanese encephalitis

In 2006, millions of Indian children lined the halls of village clinics, schools, and community centers, waiting their turn for a shot that would protect them against Japanese encephalitis, or “brain fever.” They were taking part in an unprecedented and far-reaching immunization campaign launched by the Government of India in response to a 2005 outbreak that killed 1,700 people, mostly children, and disabled thousands more.

The following year, the government’s campaign reached 20 million, bringing the number protected to more than 30 million kids. This year, the program aims to reach 20 million more.

The successful vaccination campaign is cause for much celebration, given that Japanese encephalitis is considered a neglected disease in many parts of the world. PATH has been working to build awareness throughout Asia and the Western Pacific region, where Japanese encephalitis is endemic. We’re helping India and other countries in the region understand the disease and introduce an affordable, lifesaving vaccine to protect against it.

A hidden toll

Japanese encephalitis (JE) is neglected in part because it’s virtually unheard of in the industrialized world. Hosted by pigs and wading birds and transmitted by mosquitoes, the virus mainly strikes poor rural communities in Southeast Asia and the Western Pacific. The World Health Organization (WHO) estimates that JE claims 10,000 to 15,000 lives a year. But because awareness is low and the disease is tough to diagnose, these figures may be gross underestimates.

Even less understood is the lifelong toll that JE takes on its survivors. PATH is working with our country partners to measure the burden of disability caused by JE. Up to half of survivors can suffer neurological damage that will affect them for the rest of their lives. Shadow Lives, a short video produced by PATH, tells the story of three families’ experience with JE.

Partnerships for protection

The only way to effectively control JE is through vaccination. PATH has been collaborating with national governments in India, Sri Lanka, Nepal, and other countries, as well as with WHO and UNICEF, to equip policymakers with the tools they need to make appropriate decisions on JE control. That means helping establish robust, sustainable systems for diagnosing JE, tracking its incidence, and modeling the cost-effectiveness of introducing vaccine. For example, our projects in Cambodia and Indonesia have provided important data on JE disease burden that officials are now using to develop plans for JE control through immunization.

Another important consideration is whether live JE vaccine can safely be given with the routine measles vaccination that a child receives. To address this issue, we conducted a trial during which live JE vaccine was given at the same time as live measles vaccine. After reviewing the data, WHO’s Global Advisory Committee on Vaccine Safety concluded that the short-term safety profile of live JE vaccine given with measles vaccine was acceptable. Although giving the vaccines together did appear to result in a small impact on measles immunogenicity shortly after vaccination, we are conducting a follow-up study to examine the possible long-term impact on protection, if any. Providing the two vaccines together could be an important benefit for JE vaccine introduction in resource-poor settings, where families have a hard time getting to an immunization clinic. For more information on the WHO conclusion, see the Weekly Epidemiology Record, volume 83 (pages 37 to 44), on WHO's website.

In addition to being proven safe and effective, live JE vaccine must also be affordable for use in low-income countries. PATH negotiated with vaccine manufacturer Chengdu Institute of Biological Products to establish a special public-sector price—the only way developing countries can afford to bring the vaccine to poor children who are at highest risk.

PATH and our partners envision a world where every affected country has the information and political will needed to effectively, efficiently, and safely control JE—and where every child at risk of JE infection is protected early in life by a safe, efficacious, and affordable vaccine.

Read more about PATH’s leadership in stopping Japanese encephalitis.