A new Covid-19 variant known as “Nimbus” is spreading quickly and could trigger a summer rise in infections, scientists have warned.
The strain, officially called NB.1.8.1, is a descendant of Omicron. It has already driven case increases in parts of Asia and has been detected in the UK. Health officials say current testing levels are lower than during the pandemic, so the true number of cases may be higher.
Recent UK data show Covid positivity rates are at their highest level this year, nearly doubling since March. Experts believe immunity from past infections and earlier vaccinations may now be fading, making some people more vulnerable.
Early laboratory findings suggest Nimbus may spread more easily and partially evade immunity. However, there is no evidence so far that it causes more severe illness than earlier variants.
Symptoms appear similar to previous strains and include fatigue, fever, muscle aches, and sore throat.
Health authorities are monitoring the variant closely. Vaccines currently in use are expected to remain effective in reducing severe illness and hospitalisation.
Older adults, care home residents, and people with weakened immune systems are urged to stay up to date with recommended boosters. Experts say vaccination remains the best protection against serious disease as the virus continues to evolve.