Scientific and public health knowledge must be communicated efficiently to the public during a health crisis to allow communities to respond, recover, and prepare. Public briefings and national campaigns are important components of this communication, and sign language interpreting may be an element of this process. This paper examines the experiences of sign language interpreters during the COVID-19 crisis in Ireland and the UK, and explores their role in providing access to scientific and public health information for the Deaf or hard of hearing (DHH) community. Findings in this study are based on interviews conducted in the first half of 2020 with 16 Irish Sign Language (ISL) or British Sign Language (BSL) interpreters or science communicators, 11 of whom had direct experience of interpreting during COVID-19 public briefings. These interviews constitute authentic accounts of sign language interpreters working during a global health crisis. Interviews were qualitatively analysed using theoretical assumptions from Witter-Merithew and Nicodemus (2010) about the development of specialisation among sign language interpreters to discuss how specialised competence and scientific understanding factored into participants' experiences and to derive lessons to inform future crises.