NeuroCOVID: it's time to join forces globally.

Since the recognition of the severe acute respiratory syndrome coronavirus 2 outbreak in December, 2019, there are now over 22·1 million COVID-19 cases worldwide, with more than 780 220 deaths. Reports of neurological manifestations associated with COVID-19 range from mild (headache, hyposmia, ageusia, myalgia, and fatigue or sleepiness) to severe (encephalopathy, ischemic and haemorrhagic strokes, seizures, hypoxic-ischaemic brain injury, and Guillain-Barré and other autoimmune syndromes),1, 2, 3 with prevalence rates ranging from 6% to 84%.1, 2, 3 The true prevalence, underlying mechanisms (infectious, autoimmune, secondary to systemic complications), and outcomes of COVID-19 neurological manifestations remain a key knowledge gap.

Many global initiatives have emerged to address these critical questions. The rapid and parallel implementation of these initiatives in a pandemic has resulted in discrepant data elements and definitions of neurological symptoms and signs. Furthermore, fragmented scientific approaches and overlapping consortia, in which centres can contribute data to multiple registries, raise the possibility of double-counting in future meta-analysis. All of these factors threaten the scientific rigour and yield of these combined global efforts. To address this issue, the European Academy of Neurology (EAN) and the Neurocritical Care Society (NCS)-endorsed Global Consortium Studies of Neurological Dysfunction in COVID-19 (GCS-NeuroCOVID) established a formal collaboration, thus forming the largest global network to date. An important research priority is to develop consensus and harmonisation of data elements with uniform definitions, which was emphasised in a recent Editorial in The Lancet Neurology.

The design and principals of the GCS-NeuroCOVID consortium studies were previously reported. The GCS-NeuroCOVID group, in close partnership with the Pediatrics Neurocritical Care Research Group, formed and rapidly developed a paediatrics arm of the consortium to investigate the effects of COVID-19 in children and adolescents. Currently, the GCS-NeuroCOVID consortium includes 123 sites registered for adults and 96 sites registered for paediatrics across all continents (appendix).

In parallel, the EAN created a prospective registry (The EAN Neuro-COVID Registry Consortium [ENERGY]) to evaluate the prevalence of neurological manifestations in confirmed COVID-19 cases and their outcomes at 6 months and 12 months. So far, over 254 sites have registered to ENERGY from 69 countries and three continents. This initiative was preceded by a survey of 2343 clinicians on neurological manifestations, completed on April 27, 2020, by the EAN-core COVID-19 task force.

Together, this new global collaborative effort has extensive global outreach, with 473 sites representing all continents (appendix). In addition to global data elements and the harmonisation of definitions, this collaborative brings together complementary neurological expertise from acute resuscitation and critical care to outpatient clinic and rehabilitation settings, encompassing all ages of the population. This strong global collaborative infrastructure will serve as a crucial framework for current and future pandemics that threaten global neurological health.