Arcturus: what you need to know about the latest COVID-19 variant
June 6, 2023
Is COVID-19 changing?
As we find ourselves grappling with yet another twist in the global pandemic, a new Covid-19 subvariant, christened ‘Arcturus’, has surfaced in Australia. This variant, which marks another chapter in the Omicron saga, was first identified in India in January and has since sparked a rise in infections. Following this development, health authorities reinstated mask mandates in certain parts of Australia including in health and medical settings. The World Health Organisation (WHO) has now declared Arcturus a ‘variant of concern’, with particular emphasis on its unique symptom of conjunctivitis, particularly in children.
However, tracing the origins and spread of Arcturus has proved challenging due to limited data. Early estimates suggest it could be as much as 20% more transmissible than its predecessor, the Kraken variant. Alarmingly, Arcturus, just one of 600 Omicron sub variants, appears to have improved its evasive manoeuvres around our immune system.
Although fears of a new variant understandably spark concerns about severity, current data shows that Arcturus doesn’t induce any harsher illnesses than Kraken. This observation aligns with the stagnant hospitalisation rates in countries experiencing large Arcturus spikes. Currently, Arcturus represents around 5% of all cases in Australia, indicating its growing presence in the country.
Despite Arcturus making its debut in Australia in February, its impact remains relatively low risk globally compared to other circulating variants. Nonetheless, the WHO underscored the need for vigilance, designating Arcturus as a variant of interest in light of the burgeoning cases in India.
Where do sub variants arise from?
Arcturus and its sibling variant, XBB.1.5, detected in Australia in January, both hail from the Omicron family of the SARS-CoV-2 virus. Despite its rising prominence, a comprehensive study of the Australian population revealed that Arcturus essentially presents more of the same challenge. Although it displays equal evasiveness towards antibodies, the potential implications for regions like southeast Asia cannot be understated. However, Australia’s unique trajectory through the pandemic may present a different picture.
Arcturus, while not proliferating as rapidly in the UK as in India, has been detected in over 20 countries, including the US and Canada. The subvariant presents with a range of symptoms including a steady fever, headaches, body pains, abdominal discomfort, and a sore throat. Amidst all these developments, a unique symptom associated with Arcturus is causing a stir. Reports out of India, where Arcturus has been rampant, describe cases of viral conjunctivitis, or “pink eye,” which marks a departure from typical COVID-19 symptoms. In addition, other regular signs of Arcturus infection may include a continuous cough, high temperature, changes in taste or smell, and shortness of breath. In the Australian context, the Arcturus variant has caused an 8.2% drop in average daily cases in the week ending April 11. However, COVID-19 related hospitalisations are still on the rise, with a 13.3% increase, and a remarkable 46% jump in Victoria alone. Despite these alarming figures, the Arcturus variant doesn’t seem to be associated with more severe disease.
What’s next for COVID-19?
Globally, major COVID-19 waves are happening every six months as new variants emerge and immunity wanes. The winter waves have historically recorded higher deaths per capita, compounded by general health issues and increased indoor socialising, making us more vulnerable. To combat this, mask-wearing, maintaining distance, and practising hand hygiene are recommended. Those aged 60 and above are also advised to consider antiviral treatments.
As winter draws near and cases are slowly increasing week-over-week, health experts are advocating for a more significant portion of the population to receive COVID-19 booster shots. With approximately 70% of Australians having received their booster, there’s still some way to go to reach the recommended 90-95%.
The Arcturus variant has also been detected in other countries including the USA, UK, and at least 34 other nations. The rapid global spread and the unique symptomatology of Arcturus highlight the continuous need for vigilance in our ongoing battle against COVID-19. While current vaccines and therapeutics remain broadly effective, ongoing scientific investigation is crucial for ensuring our preparedness and response to this ever-evolving virus. As such, timely administration of booster shots and adherence to safety guidelines remain our best lines of defence.
Looi M. What do we know about the Arcturus XBB.1.16 subvariant? BMJ 2023; 381 :p1074 doi:10.1136/bmj.p1074
Konings et al. SARS-CoV-2 Variants of Interest and Concern naming scheme conducive for global discourse, Nature Microbiology 2021 Jul;6(7):821-823
