Developing and scaling up a vaccine for contagious bovine pleuropneumonia
Researchers in Kenya and Canada collaborated with vaccine manufacturers, government regulators, and pan-African organizations to clear the way for the mass production of a practical and affordable vaccine to protect against contagious bovine pleuropneumonia (CBPP). In a global first, the project team developed a CBPP vaccine that is safe, highly effective, prolongs immunity, reduces side effects, and can be easily stored and transported, with no cooling required — making it practical and accessible for small-scale livestock keepers in Kenya and other African countries.
Developing an effective and affordable vaccine
CBPP is a highly contagious respiratory disease of cattle that has serious economic and trade implications across Africa. The disease affects the livestock of approximately 24 million primarily low-income African farmers each year, causing at least US$60 million in losses annually. An existing CBPP vaccine is available on the market, but it is only effective in approximately 22% of cattle, it can have severe side effects, it is short-lived, and it requires refrigeration, making it impractical in many parts of Africa.
In a previous project supported by the Canadian International Food Security Research Fund (CIFSRF), Canadian and Kenyan researchers developed three promising vaccine candidates. This second phase of the project supported further studies that were needed to determine which vaccine and formulation offered the greatest protection against CBPP and could be affordably mass-produced. “We believe vaccination is the best way to control CBPP and to improve food security for the small-scale cattle farmers disproportionately affected by this disease,” said Jane Wachira, CEO of Kenya Veterinary Vaccines Production Institute (KEVEVAPI). “Our objective is to get this vaccine to farmers in Africa as quickly as possible.”
To do this, formulations of the experimental vaccine were tested and compared to the existing vaccine using animal trials. Engineered proteins (called protein chimeras or fusion proteins) were developed to reduce the number of antigen components (and thus the cost per dose) in the new vaccine. Then processes were developed to harvest, isolate, and purify antigen.
A high throughput processing machine was acquired — the first of its kind in sub-Saharan Africa —that can test 9,600 samples in 45 minutes, as opposed to days or weeks with existing methods. This will speed up diagnoses, reduce the number of false positives, lower treatment costs, and improve surveillance and control programs. A product development centre was launched in Kenya and staff were trained to produce the antigens in-country.
A licensing agreement for commercial production and marketing was finalized between the Kenya Veterinary Vaccines Production Institute (KEVEVAPI) and three intellectual property-holder institutions: Kenya Agricultural and Livestock Research Organization (KALRO), the International Livestock Research Institute (ILRI), and the University of Saskatchewan’s Vaccine and Infectious Disease Organization – International Vaccine Centre (VIDO-InterVac).
Overcoming the social and economic barriers to widespread vaccine adoption
Once the effective CBPP vaccine was developed, there was also a need to identify the socio-economic factors that would increase the likelihood of farmers using the new vaccine. The project is also working with social scientists and economists to overcome regulatory, gender, or cost issues that may affect distribution and acceptance of the vaccine.
The highest national and sub-national authorities in Kenya’s Laikipia County were involved in communicating the risk of CBPP to farmers in a high-impact awareness campaign that received national media coverage. Although most livestock owners perceive vaccination as the only effective control measure for CBPP, vaccination coverage in endemic areas has been low. Studies showed that farmer use of the current vaccine was influenced by the number of cattle owned, the age of the livestock owner, household income and size, and previous experience of CBPP in the herd. Willingness-to-pay studies showed that livestock keepers are generally willing to pay for CBPP vaccines, but their ability to do so is cost-dependent.
Cost-benefit analyses provide sound business rationale for poor farmers to purchase the vaccine and for the use of public funds to control the disease. The vaccine is expected to have a positive impact on food productivity by reducing the number of cattle that become infected; creating more stable market prices; lowering intervention costs to control the spread of the disease; and reducing reliance on antibiotics. These benefits will save money and reduce the risk of increased antibiotic resistance.
A study indicated that CBPP rates are predicted to increase from 14% to 18% by 2030 at the rate of control with the current vaccine. A need for greater coordination and regulation in CBPP vaccination between national government and counties was identified, as well as greater awareness of national, regional, and international CBPP control strategies.
The project team prepared a CBPP control strategy and contingency plan in Kenya and provided national training on CBPP surveillance in collaboration with the African Union Inter-African Bureau for Animal Resources.
KALRO scientists received a public service excellence award from the Kenyan government in recognition of their outstanding commitment to developing the vaccine. KALRO has committed half the funding needed (CA$2.5million) for a large-scale field trial in commercial cattle to assess safety, efficacy, and duration of immunity of the vaccine. Commercial production is on schedule to begin in 2019.
Merck has provided funding that will allow KALRO and KEVEVAPI to continue limited large-scale production of antigens and consultations are ongoing with Merck for further scale-up. Expanded manufacturing partnerships will include additional African and European companies.
The Canadian International Food Security Research Fund is jointly funded by IDRC and Global Affairs Canada.