Covid-19 remains widespread, but hospitalisations have dropped significantly, raising questions about the reasons behind this shift. Experts are grappling with the mystery, especially after the emergence of XEC, a new Covid-19 variant that gained prominence in autumn 2024.

XEC, a descendant of the Omicron variant, has raised alarms among virologists due to its potential to evade immunity from previous infections and vaccines. The variant arose through recombination, a process where genetic material from two other variants fused together. Early tests suggested XEC could bypass protection offered by past infections and the latest Covid-19 vaccines, particularly those targeting the older JN.1 and KP.2 variants.

However, despite concerns, the expected surge in hospitalisations following the Thanksgiving holiday in the United States did not materialize. While surveillance testing revealed widespread infection of XEC through wastewater samples, hospitalisation rates remained remarkably low. According to the Centers for Disease Control and Prevention (CDC), hospitalisation rates at the start of December 2024 were just two per 100,000 people, a sharp decline from the previous year’s rate of 6.1 per 100,000.

Peter Chin-Hong, a professor of Infectious Diseases at the University of California, San Francisco, noted that, despite the high levels of Covid detected, few patients are critically ill. “It just shows that regardless of how scary a variant might look in the lab, the environment in which it lands is much more inhospitable,” he explained.

Experts have suggested that Covid-19 in 2025 may have become a milder disease. Common symptoms such as loss of taste and smell are becoming less frequent, and most people now experience mild cold-like symptoms, often mistaken for seasonal allergies. While immunocompromised individuals and the elderly are still at higher risk, Chin-Hong believes that Covid has become much less severe overall.

Despite this, experts caution that Covid-19 remains a persistent threat to public health. The risk of long Covid, while decreasing, still looms for some individuals, and the possibility of more severe variants emerging in the future cannot be ruled out. As a result, health authorities continue to recommend that vulnerable populations receive the latest Covid-19 vaccines, which can offer protection against serious illness, hospitalisation, and death.

Microbiologist Harm Van Backel, co-leader of the Mount Sinai Pathogen Surveillance Program, noted that, despite the emergence of XEC, Covid-19 has contributed relatively little to hospitalisation rates this winter, with other respiratory viruses taking precedence. He attributed the lower hospitalisation rates to more effective treatments and better immunity in the population.

While Covid-19 may have become less invasive, experts caution that the situation remains unpredictable. Long-term effects, such as persistent gastrointestinal infections linked to Covid, are still being studied. Research continues to focus on developing next-generation vaccines and therapies to better control the virus and its potential future evolution.