| Institution: | 1. Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis;2. Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa;3. Center for One Health Research and Policy Advice, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region;1. Toronto General Hospital Research Institute, University Health Network, Toronto, Canada and Department of Immunology, University of Toronto, Toronto, Canada;2. Bandim Health Project, Department of Clinical Research, Odense University Hospital, University of Southern Denmark, Denmark;3. Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA |
| Abstract: | The benefits of vaccines have been centred on their specific effects on subsequent infections by target pathogens. Recent studies, however, have opened up new insights into additional effects of vaccines known as non-specific effects (NSEs) or heterologous effects of vaccines. While several articles have reviewed epidemiological and immunological evidence for NSEs of vaccines in humans, similar works on veterinary vaccines are scarce. The objective of this paper was to review the findings of published studies on NSEs of vaccines developed or repurposed for use in animals. In total 8412 titles were retrieved from PubMed and CABI databases on the 30th of April 2021. After the final stage of screening, 45 eligible articles were included in the review. Data from these articles were summarised and presented here. In general, most of the vaccines studied in the reviewed articles have beneficial NSEs against multiple pathogens and disease conditions. There were, however, fewe studies reporting detrimental NSEs from both non-live and live vaccines which is in contrast to the currently existing evidence of beneficial NSEs of live vaccines and detrimental NSEs of non-live vaccines. This review may be used as a complement for future review of RCT studies of NSEs of vaccines in animals and provide a useful addition to the evolving understanding of the NSEs of vaccines. |
