Washington: Rabies vaccines stored at warmer temperatures still protect against the disease in dogs, according to a new research which can improve the vaccination coverage in hard to reach, rural areas in Asia and Africa where electricity for cooling is limited.
Researchers from Washington State University in the US, found that Nobivac, a commonly used rabies vaccine, produces the same level of protective antibodies in dogs after being stored for six months at 25 degrees Celsius and for three months at 30 degrees Celsius. "Thermotolerant vaccines were a really important feature of the campaign to eliminate smallpox. We hope it will have the same effect for eradicating rabies," said lead author Felix Lankester, assistant professor in the WSU.
Recommendations by the World Health Organisation (WHO) are for vaccines to be transported and stored in a "cold chain" at between two and eight degrees Celsius. "The ability to distribute vaccines widely outside the cold chain will allow for more consistent coverage across communities. It could be a quantum shift in how vaccines are delivered," said Lankester.
"Human rabies from dog bites has the highest fatality rate of any human infectious disease. It is easily preventable with regular dog vaccinations," said Guy Palmer, from WSU. Each year roughly 60,000 people, mostly children, die
from rabies. Globally, more than 99 per cent of human rabies deaths are caused by dog bites - almost all in sub-Saharan Africa and Asia.
Millions of people are saved by costly post-exposure prophylaxis - a series of post-bite vaccinations, the first of which must be administered within the first 24 hours after a person is bitten by a rabid dog. Once symptoms appear, the disease is fatal.
Vaccinating 70 per cent of the dog population will protect humans and wildlife, such as endangered African wild dogs, from the disease. WSU has been working to control rabies in areas of northern Tanzania through annual mass dog rabies vaccination campaigns. However, rabies continues to be prevalent, in part
because of the challenges of transporting vaccines to remote areas where vulnerable people live in resource-poor communities.
"If a team-led vaccination campaign misses a village because it is very far or because rain washed out a bridge, then there will be pockets where vaccination coverage is low. With a community-led initiative, we are hopeful we would
improve the coverage levels," said Lankester. Mass vaccination teams generally only visit communities once a year, if they can get there at all. When new dogs are born or move into the community, the level of protection against rabies drops.
In community-led programmes, thermotolerant vaccines could be stored in the community where local coordinators would vaccinate the entire dog population. The study appears in the journal Vaccine.
