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RABIES: Scientists want delivery of mass dog vaccination campaigns in Tanzania improved

March 1, 2022
RABIES: Scientists want delivery of mass dog vaccination campaigns in Tanzania improved
Street dogs captured by researchers in the study during a vaccination campaign in Kisarawe in May 2021. PHOTO | FILE/Courtesy of Maganga Sambo.

After assessing mass dog vaccination campaigns in Tanzania for seven years, researchers from Ifakara Health Institute and five partner institutions have underlined a need to improve delivery of the campaigns in order to achieve the global target of zero dog-mediated human rabies deaths by 2030.

In their new findings published on the PLOS journal on February 10, 2022, the researchers also encouraged monitoring and evaluation of the campaigns, indicating that it is essential to measure progress towards the elimination of dog rabies in the country.

“We recommend national programs regularly monitor and evaluate the performance of their vaccination campaigns, so as to identify factors hindering their effective delivery and to guide remedial action,” they say in their paper published on the PLOS section for neglected tropical diseases. Ifakara researchers who participated in the study are: Maganga Sambo, Joel Changalucha, and Kennedy Lushasi.

The researchers issued the recommendation against the backdrop of poor performance of most of the campaigns conducted from 2010-2017 revealed by the same study, during which only 16–28% of districts achieved 100% campaign completeness.

“During 2010–2017, five rounds of vaccination campaigns were carried out, vaccinating in total 349,513 dogs in 2,066 administrative vaccination units (rural villages or urban wards). Progressively, more dogs were vaccinated over the successive campaigns,” they say, noting however that, “the campaigns did not reach all vaccination units each year, with only 16–28% of districts achieving 100% campaign completeness (where all units were vaccinated).”

An increasing number of countries are committed to meeting the global target to eliminate human deaths from dog-mediated rabies by 2030, and to achieve this target, mass dog vaccination has been central to this strategy.

The Tanzanian government through the Ministry of Livestock Development and Fisheries in collaboration with development partners had implemented dog vaccination campaigns to control the disease as per the WHO recommendations that dog vaccinations should be carried out every year in all dog-owning communities vaccinating 70% of their susceptible dogs. These interventions which initially began in 2010, have so far only covered a few districts in Tanzania and as a result, dog rabies remains uncontrolled across most of the country.

Particularly, the study monitored and evaluated the performance of the dog vaccinations delivery campaigns implemented in 25 districts in southeast Tanzania from 2010 to 2017. The study was done through the Rabies Elimination Demonstration Project, a large-scale intervention coordinated by the World Health Organization and funded by the Bill and Melinda Gates Foundation.

By focusing on the coverage, completeness, and timeliness achieved and identifying factors associated with the campaign performance, findings from the study showed coverage gaps due to incomplete implementation of the vaccinations. Additionally, vaccinations were not implemented annually and, as a result, coverage dropped below the critical vaccination threshold.

In Tanzania, dog rabies was first documented in 1932. Since then, the disease has spread widely throughout the country with varying patterns of infection between regions depending very much on the size of dog populations. As in most of the developing world, the domestic dog is the most important source of human rabies in Tanzania and causes an estimated 552 (394–731) human deaths annually.

The study was approved by the Medical Research Coordinating Committee of the National Institute for Medical Research of Tanzania, the Institutional Review Board of the Ifakara Health Institute, and the Tanzania Commission for Science and Technology (COSTECH).

Researchers who participated in the study came from Ifakara Health Institute and five other partner institutions. The other five are: Boyd Orr Centre for Population and Ecosystem Health, University of Glasgow, United Kingdom; Department of the Control of Neglected Tropical Diseases, Geneva, Switzerland; Ministry of Health, Tanzania; Department of Neglected Tropical Diseases of World Health Organization - Country Office of Tanzania; and the Directorate of Veterinary Services, Ministry of Livestock Development and Fisheries, Tanzania.