Shark conservation risks associated with the use of shark liver oil in SARS-CoV-2 vaccine development

The COVID-19 pandemic may create new demand for wildlife-generated products for human health, including a shark-derived ingredient used in some vaccines. Adjuvants are a vaccine component that increases efficacy, and some adjuvants contain squalene, a natural compound derived from shark liver oil which is found most abundantly in deep-sea sharks. In recent decades, there has been growing conservation concern associated with the sustainability of many shark fisheries. The need for a potentially massive number of adjuvant-containing SARS-CoV-2 vaccines may increase global demand for shark-derived squalene, with possible consequences for shark conservation, especially of vulnerable and understudied deep-sea species. A shift to non-animal-derived sources of squalene, which are similar in cost and identical in effectiveness, or an emphasis on increasing traceability and sustainability of shark-derived squalene from existing well-managed fisheries, could better support conservation and public health goals.