Thermotolerance of an inactivated rabies vaccine for dogs

Abstract

This study provides the first robust data that the antibody response of dogs vaccinated with Nobivac® Rabies vaccine stored for several months at high temperatures (up to 30°C) is not inferior to that of dogs vaccinated with vaccine stored under recommended cold-chain conditions (2-8°C). A controlled and randomized non-inferiority study was carried out comparing the four-week post vaccination serological responses of Tanzanian village dogs inoculated with vaccine which had been stored at elevated temperatures for different periods of time with those of dogs vaccinated with the same product stored according to label recommendations. Specifically, the neutralizing antibody response following the use of vaccine which had been stored for up to six months at 25°C or for three months at 30°C was not inferior to that following the use of cold-chain stored vaccine. These findings provide reassurance that the vaccine is likely to remain efficacious even if exposed to elevated temperatures for limited periods of time and, under these circumstances, it can safely be used and not necessarily destroyed or discarded. The availability of thermotolerant vaccines has been an important factor in the success of several disease control and elimination programs and could greatly increase the capacity of rabies vaccination campaigns to access hard to reach communities in Africa and Asia. We have not confirmed a 3-year duration of immunity for the high temperature stored vaccine, however because annual re-vaccination is usually practiced for dogs presented for vaccination during campaigns in Africa and Asia this should not be a cause for concern. These findings will provide confidence that, for rabies control and elimination programs using this vaccine in low-income settings, more flexible delivery models could be explored, including those that involve limited periods of transportation and storage at temperatures higher than that currently recommended.

Recommendations on vaccination for Latin American small animal practitioners: a report of the WSAVA Vaccination Guidelines Group

“…In this context, the recommendation would always be to contact the manufacturer of the vaccines to ask for advice. Recent studies suggest that international killed rabies vaccines may actually be quite thermotolerant, but these studies are done against the background of mass vaccination in the field and not from the perspective of practicing quality veterinary medicine in the veterinary clinic (Lankester et al 2016) [EB1].…”

Successful strategies implemented towards the elimination of canine rabies in the Western Hemisphere

“…Alternatively, some countries have instituted minimum potency requirements in their purchasing and acquisition policies, as a means to ensure that the vaccine will adequately immunize dogs when used in the field, even if cold-chain conditions are not ideal. Recently, thermotolerant and thermostable vaccine formulations seem to be an excellent alternative to overcome cold-chain constraints and to expand coverage with acceptable immunization results ( Lankester et al, 2016 ; Smith et al, 2015 ).…”

Controlling Human Rabies: The Development of an Effective, Inexpensive and Locally Made Passive Cooling Device for Storing Thermotolerant Animal Rabies Vaccines

“…In recent years, efforts have been directed to address the challenges of storing rabies vaccine in remote areas without cold chain infrastructure. A study conducted in 2015 determined that the Nobivac TM Canine Rabies vaccine (MSD Animal Health, Boxmeer, The Netherlands) remained potent following storage at 25 °C for six months and at 30 °C for three months [ 16 ]. These findings opened up the possibility of storing these vaccines outside of refrigeration units, an outcome that could benefit rabies control in remote areas where electricity provision is poor.…”

“…These findings opened up the possibility of storing these vaccines outside of refrigeration units, an outcome that could benefit rabies control in remote areas where electricity provision is poor. Nonetheless, keeping vaccines in such locations would still require some form of storage and given that temperatures over 30 °C were shown to impact vaccine potency [ 16 ], the temperature inside storage units should be as cool as possible. This study describes the development and subsequent testing of a PCD to store rabies vaccines for extended periods in advance of and during MDV campaigns.…”