The emergence of the JN.1 variant of Sars-CoV-2, a sub-lineage of the Omicron strain, has sparked concerns globally. As the first case in India makes headlines, countries worldwide face a renewed battle against the evolving virus.
Understanding the JN.1 variant
The JN.1 variant, a sub-lineage of BA.2.86 (Pirola), has been identified by the World Health Organization (WHO) as a Variant of Interest (VOI). With origins traced to Denmark and Israel, the JN.1 variant possesses a unique genetic makeup, marked by an additional substitution in the spike protein (L455S). This modification has raised concerns among experts, suggesting potential increased transmissibility or immune evasion.
Global circulation
Global Initiative on Sharing All Influenza Data (GISAID) data reveals that over 6,600 samples of BA.2.86 and its sub-lineages, including JN.1, have been sequenced across several countries, such as China, the UK, Iceland, Spain, Portugal, and the Netherlands. The United States Centers for Disease Control and Prevention (CDC) detected the JN.1 variant in September 2023, signifying its continued growth on a global scale.
Impact on outbreaks
As JN.1 becomes the dominant strain in various nations, the WHO urges heightened surveillance and sequencing efforts. Notably, Spain, Singapore, Brazil, Belgium, the Netherlands, and Malaysia report JN.1 in over 50% of sequenced samples. Singapore, facing a significant resurgence in cases, reinstated mandatory masking in crowded places, demonstrating the urgency with which nations are responding to the threat.
Surge in India and the United States
India has witnessed a spike in infections, prompting the Union Health Ministry to call for increased COVID-19 surveillance. In the United States, the CDC projects a rising proportion of Sars-CoV-2 genomic sequences attributed to JN.1. While infection numbers surge, daily death rates remain relatively stable, indicating a potential shift in the virus's behavior.
Symptoms and severity
Despite the surge in cases linked to JN.1, global data shows a lower reported severity compared to previous variants. Singapore, for instance, reports no deaths attributed to Covid-19 since early November. The US records a decline in the seven-day average of daily deaths, reinforcing the notion that JN.1 may not cause more severe outcomes.
Vaccine efficacy
Encouragingly, both the WHO and CDC affirm that existing vaccines remain effective against the JN.1 variant. Sera from patients with Omicron breakthrough infections exhibit robust neutralizing activity against BA.2.86, indicating potential cross-protection against JN.1. This positive outlook extends to Covid-19 tests and treatments, expected to remain effective against the evolving virus.
Expert opinion
Coming to X, formerly Twitter, Director of the Allergy, Immunology, and Cell Biology Unit of the Sri Jayewardenepura University, Dr. Chandima Jeewandara, sheds light on the situation in Sri Lanka. Dr. Jeewandara emphasises that Covid is not as simple as the common cold, with severe illness and long-term effects, including an increased risk of heart attacks, strokes, and mental health problems. Despite the current low testing rates in Sri Lanka, Dr. Jeewandara warns that the JN.1 sub-variant may already be in the community, given the observed increase in Influenza-Like Illness (ILI) cases. He advises those with poor immunity or elderly individuals to start masking up, especially in poorly ventilated, closed, and crowded environments.