Widespread canine rabies vaccination reduces mortality in low-income countries

The approximately 59,000 annual human deaths from the rabies virus could be prevented through domestic dog vaccination, according to a recent study.

Additionally, the study found that rabies results in annual economic losses of $8.6 billion U.S. dollars, primarily due to premature deaths, but also due to spending on human vaccines and income lost by victims of animal bites.

“This groundbreaking study is an essential step towards improved control and eventual elimination of rabies,” Louis H. Nel, PhD, executive director of the Global Alliance for Rabies Control, said in a press release. “An understanding of the actual burden helps us determine and advocate for the resources needed to tackle this fatal disease.”

In the study, the researchers expanded on existing model frameworks to evaluate the status of canine rabies globally and on a country-by-country basis.

Researchers modified a decision-tree model framework which used the product of bite incidence, and determined the probability of the following: 1) a biting animal being rabid; 2) a bite victim receiving post-exposure prophylaxis (PEP) or 3) in the absence of PEP, a victim developing rabies, to determine human rabies deaths and disability-adjusted life years (DALYs). They also calculated the cost of rabies prevention and control, including PEP administration, surveillance, and livestock losses from rabies.

The researchers applied parameters to the model using country-specific data or cumulative cluster estimates. In areas where rabies was typically found, the researchers theorized that the incidence of dog rabies corresponded with vaccine coverage in the dog population, and that the probability that a dog bite is from a rabid animal was linked to incidence.

The researchers found that the burden of rabies on public health, public sector budgets, local communities, and livestock economies is significant, and that the poorest areas of the world are at the highest risk of rabies. The death rate from rabies (represented in deaths per 100,000 population) was highest in sub-Saharan Africa, and the overall highest number of annual fatalities were reported in India (20,847 human deaths per year). Across almost all countries of Africa and Asia, dog vaccination coverage was considered well below what is needed to control the disease.

“The breadth of data used in this study, from surveillance reports to epidemiological study data to global vaccine sales figures, is far greater than ever analyzed before, allowing this more detailed output,” Katie Hampson, PhD, of the University of Glasgow, said in the press release.

Because rabies is close to 100% fatal but also almost 100% preventable, the researchers emphasized the importance of dog vaccination in controlling rabies. In particular, the researchers noted that increased efforts are needed in impoverished countries.

“A greater focus on mass dog vaccination could eliminate the disease at source, reducing the need for costly PEP and preventing the large and unnecessary burden of mortality on at-risk communities,” the researchers wrote in the study.

Disclosure: Coudeville, Kieffer and Attlan report being employed by Sanofi Pasteur and Schumacher reports employment by Merial.