Grappling with (re)-emerging infectious zoonoses: Risk assessment, mitigation framework, and future directions

Low-income countries (LICs) in Africa, southeast Asia, Latin America, and the Caribbeans constitute potential hotspots for future outbreaks of zoonoses. A comprehensive framework on risk drivers, assessment, and mitigation in LICs is lacking. This paper presents the nature, history, risk factors, and drivers of zoonoses in LICs. A Quantitative Microbial Risk Assessment and Hazard Analysis of Critical Control Points are proposed for assessing human health risks. The mitigation framework entails: (i) learning from the COVID-19 pandemic, (ii) the precautionary principle, (iii) raising public and stakeholder awareness, and (iv) the One World, One Health concept. Future perspectives are discussed on: (i) curbing poaching and illicit wildlife trade, (ii) translating the ‘One Health’ concept to practice, (iii) the dilemma of dealing with wildlife hosts of zoonoses, including the morality and ethics of culling versus non-culling, (iv) the challenges of source tracking and apportionment of zoonoses, and (v) decision scenarios accounting for the high human health risks and the high uncertainty in current evidence. Future directions on zoonoses include: (i) the occurrence of antimicrobial resistance, (ii) environmental reservoirs and hosts, (iii) the development of tools for source tracking and apportionment, and (iv) host-receptor-pathogen interactions. Funding models and the application of novel tools, i.e., game theory, genomics, shell disorder analysis, and geographical information systems, are discussed. The proposed framework enables a better understanding of the key risk drivers, assessment, and mitigation in LICs. Further work is needed to test and validate the framework and develop generic lessons for risk assessment and mitigation in LICs.

COVID-19 Vaccine Boosters: The Good, the Bad, and the Ugly.

Pursuing vaccinations against COVID-19 brings hope to limit the spread of SARS-CoV-2 and remains the most rational decision under pandemic conditions. However, it does not come without challenges, including temporary shortages in vaccine doses, significant vaccine inequity, and questions regarding the durability of vaccine-induced immunity that remain unanswered. Moreover, SARS-CoV-2 has undergone evolution with the emergence of its novel variants, characterized by enhanced transmissibility and ability to at least partially evade neutralizing antibodies. At the same time, serum antibody levels start to wane within a few months after vaccination, ultimately increasing the risk of breakthrough infections. This article discusses whether the administration of booster doses of COVID-19 vaccines is urgently needed to control the pandemic. We conclude that, at present, optimizing the immunity level of wealthy populations cannot come at the expense of low-income regions that suffer from vaccine unavailability. Although the efficiency of vaccination in protecting from infection may decrease over time, current data show that efficacy against severe disease, hospitalization, and death remains at a high level. If vaccine coverage continues at extremely low levels in various regions, including African countries, SARS-CoV-2 may sooner or later evolve into variants better adapted to evade natural and vaccine-induced immunity, ultimately bringing a global threat that, of course, includes wealthy populations. We offer key recommendations to increase vaccination rates in low-income countries. The pandemic is, by definition, a major epidemiological event and requires looking beyond one's immediate self-interest; otherwise, efforts to contain it will be futile.