COVID-19 has not disappeared and continues to evolve, with the World Health Organization monitoring six variants for potential public health implications. Among them are NB.1.8.1, dubbed "Nimbus," and XFG, known as "Stratus."

Here's what we know about these variants:

• 1. Rapid Spread: NB.1.8.1 has spread across Asia and beyond, while XFG has rapidly spread globally. However, there is no evidence to suggest that they cause more severe disease than other variants.
• 2. Nicknames: NB.1.8.1 was named "Nimbus" due to its unique characteristics, while XFG was dubbed "Stratus" to reflect their potential global dominance.
• 3. Genetic Recombination: Both variants are a result of genetic recombination, with NB.1.8.1 having seven new spike protein mutations and XFG containing four key spike protein mutations.
• 4. Cell Binding: NB.1.8.1 binds strongly to human cells, making it highly infectious. XFG, on the other hand, is good at evading the immune system.
• 5. Vaccine Effectiveness: Despite some reduction in antibody effectiveness, COVID-19 vaccines are still likely to offer protection against these variants.
• 6. Specific Symptoms: Symptoms of these variants are similar to other Omicron versions, with reports of unique symptoms like a "razor blade" sensation in the throat.
• 7. Monitoring: NB.1.8.1 is under monitoring by the WHO, while XFG is not considered a top-tier concern but is still under surveillance for any changes.