Development and evaluation of a novel vaccine storage device for effective vaccination strategy against rabies
| dc.contributor.author | Lugelo, Ahmed Kambinda | |
| dc.date.accessioned | 2024-01-11T06:38:54Z | |
| dc.date.available | 2024-01-11T06:38:54Z | |
| dc.date.issued | 2023 | |
| dc.description | Thesis | en_US |
| dc.description.abstract | Canine-mediated human rabies has the highest case fatality rate of any known infectious disease and kills approx. 59,000 people annually, with most deaths being children under 15 years. The vast majority (99%) of these fatalities occur in Africa and Asia, where access to appropriate Post Exposure Prophylaxis (PEP) is limited and where canine vaccination is either inconsistently applied or, commonly, non-existent. Epidemiological studies have shown that rabies has epidemiological features that make elimination a realistic and feasible goal, with success demonstrated by comprehensive mass dog vaccination programmes in the Americas, Western Europe and Japan. In rabies endemic countries, dogs are often vaccinated using annually delivered central point clinics at the village level on an annual basis. For this method to be effective at least 70% of the dog population must be vaccinated to maintain herd immunity between campaigns. However, studies have shown that only a few programmes utilising this approach have attained this level of coverage, highlighting the need for alternative approaches to address this challenge. The current study was carried out to develop an alternative strategy for delivering and maintaining herd immunity over time in low-resource field settings. Through an iterative process of improvement and testing with local communities in northern Tanzania, a passive cooling device “Zeepot” for storage of thermotolerant rabies vaccines was developed at a cost of $11 per unit. The results from a non-inferiority randomised controlled trial showed that the serological response of dogs vaccinated using Nobivac ® Rabies vaccine stored within the Zeepot was not inferior to the response of dogs vaccinated using cold-chain stored vaccine (z = 1.1, df = 313, p-value = 0.25). Indeed, the 28-day post vaccination group geometric mean titre was 1.8 IU/ml and 2.0 IU/ml for dogs vaccinated with vaccines stored under cold-chain versus non-cold-chain respectively. Moreover, the percentage of dogs that seroconverted in each arm was almost identical (85%). There was a positive linear trend between Body Condition Score (O.R. 2.2, 95% CI: 1.1 – 5.1) and seroconversion, suggesting that dogs of poor condition may not respond as expected to vaccination. Our study demonstrated that the potency of Nobivac ® Rabies vaccine is not impacted following storage in Zeepot Clay locally designed Passive Cooling Device. A total of 17,571 dogs were vaccinated in the field study that was conducted to evaluate the effectiveness of the standard delivery method also known as Central Point Vaccination (CPV) and a novel strategy, Decentralized Continuous Vaccination (DCV), 2654 dogs were vaccinated using CPV and 14,917 dogs were vaccinated through three sub-strategies of DCV. At time point 1 (1 month after the initial vaccination campaign), the vaccination coverage achieved by DCV coverage was higher (64.10%; 95CI 62.12 – 66.04) than for CPV (35.86%; 95CI 32.59 – 39.51). Similarly, at time point 2 (11 months after the vaccination campaign) the coverage in DCV (60.67%; 95CI 58.47 – 62.84) remained high while the coverage in pulse vaccination was lower (32.10%; 95CI 28.82-35.57). Overall, > 84% of the respondents were satisfied with the vaccination services they received. DCV has the potential to consistently maintain population level immunity. Overall, this thesis showed that Zeepot Clay has a utility for storing thermotolerant vaccines at sub-ambient temperatures. Moreover, DCV has the potential to consistently maintain population level immunity making it a useful strategy to further investigate for scaling up of mass dog vaccination in East Africa. Together the findings of this work have potential application for rabies elimination programmes, particularly in achieving the global target of zero human deaths by 2030 and potentially for use in other vaccination programmes aiming to reach remote or inaccessible communities. | en_US |
| dc.identifier.uri | http://www.suaire.sua.ac.tz/handle/123456789/5883 | |
| dc.language.iso | en | en_US |
| dc.publisher | Sokoine University of Agriculture | en_US |
| dc.subject | Novel vaccine storage | en_US |
| dc.subject | Vaccination strategy | en_US |
| dc.subject | Rabies | en_US |
| dc.subject | Post exposure prophylaxis | en_US |
| dc.subject | Children under 15 years | en_US |
| dc.title | Development and evaluation of a novel vaccine storage device for effective vaccination strategy against rabies | en_US |
| dc.type | Thesis | en_US |