TY - JOUR T1 - Considerations for causality assessment of neurological and neuropsychiatric complications of SARS-CoV-2 vaccines: from cerebral venous sinus thrombosis to functional neurological disorder JF - Journal of Neurology, Neurosurgery & Psychiatry JO - J Neurol Neurosurg Psychiatry SP - 1144 LP - 1151 DO - 10.1136/jnnp-2021-326924 VL - 92 IS - 11 AU - Matt Butler AU - Arina Tamborska AU - Greta K Wood AU - Mark Ellul AU - Rhys H Thomas AU - Ian Galea AU - Sarah Pett AU - Bhagteshwar Singh AU - Tom Solomon AU - Thomas Arthur Pollak AU - Benedict D Michael AU - Timothy R Nicholson Y1 - 2021/11/01 UR - http://jnnp.bmj.com/content/92/11/1144.abstract N2 - The scientific community rapidly responded to the COVID-19 pandemic by developing novel SARS-CoV-2 vaccines (table 1). As of early June 2021, an estimated 2 billion doses have been administered worldwide.1 Neurological adverse events following immunisation (AEFI), such as cerebral venous sinus thrombosis and demyelinating episodes, have been reported. In some countries, these have led to the temporary halting of both vaccine trials and roll-out programmes. In the absence of clear evidence of causal associations between the vaccine and adverse events, or the rarity of the AEFIs themselves, programmes have thus far been restarted, although sometimes with modifications to recommendations.2 View this table:In this windowIn a new windowTable 1 SARS-CoV-2 vaccines approved for use by at least one regulatory body at the time of submission (early June 2021)71 Transient influenza-like symptoms such as headache, myalgia and fatigue have been reported in up to 5% of SARS-CoV-2 vaccine recipients in clinical trials,3 4 although these symptoms often indicate an appropriate immune response to vaccination.5 More severe potential adverse effects in the open-label phase of vaccine roll-outs are being collected through national surveillance systems. In the USA, roughly 372 adverse events have been reported per million doses, which is a lower rate than expected based on the clinical trials.6 In the UK, adverse events are reported via the Coronavirus Yellow Card reporting website. As of early June 2021, approximately 250 000 Yellow Cards have been submitted, equating to around three to seven Yellow Cards per 1000 doses.7 For comparison, the 2010 Pandemrix vaccination had a rate of around 0.6 Yellow Card submissions per 1000 doses.8 Increased pharmacovigilance surrounding SARS-CoV-2 vaccinations may lead to surveillance bias,9 safety alerts may lead to notoriety bias10 and recall bias may also occur. Nevertheless, with large numbers of people being vaccinated, often with a two-dose schedule, rare complications … ER -