Europe and India are grappling with the latest COVID-19 surge, sparking intrigue about two new variants, NB.1.8.1 and LF.7, and their distinctions from the Delta and earlier Omicron strains. This article explores their differences and the potential of these new variants concerning public health.
Genetic Changes and Categorisation
As with LF.7, NB.1.8.1 is also an Omicron sub-variant. Due to some unique genetic modifications, they retain traces of Delta and older Omicron waves. These changes could support the Omicron subvariants LF.7 and NB.1.8.1 in spreading more easily and overcoming immune defences. However, no evidence suggests that all Omicron sub-variants have become deadlier. Their classification as “Variants under Monitoring” indicates that health authorities are closely tracking them, but they don’t yet pose risks as variants of concern.
Transmission Rate
Delta (2021): As the original strain of SARS-CoV-2, Delta became responsible for surging cases and was later much more prevalent than the older variants. Effectively, it was about two times more transmissible than the previous versions, speeding up the rise of cases around the Globe.
Omicron (2022–2023): It claimed dominance, eliminating further competition by replacing Delta as the main strain spread globally along with its sub-lineages BA.1, BA.2, BA.4, and BA.5, displaying unprecedented spread levels.
2025 Variants (NB.1.8.1, LF.7): Preliminary data indicates these variants continue to sustain or create a modest increase in Omicron’s exceptionally high transmissibility, which seems to be underlying the current increase in cases.
Disease Severity
Delta: Associated with more severe illness, higher rates of hospitalisation, and increased mortality, particularly in the unvaccinated, high-risk, and vulnerable populations
Omicron: While cases surged due to Omicron, most were mild, with lower severe disease and death rates than Delta. There was a notable decline in ICU admissions and deaths, especially in high-vaccination countries.
2025 Variants: The predominant symptoms associated with NB.1.8.1 and LF.7 are mild and include a sore throat, cough, mild fever, and fatigue. No evidence suggests greater severity of disease compared to Delta or early Omicron.
Immune Evasion
Delta: Experienced moderate immune escape leading to breakthrough infections, but did not significantly impact the vaccine’s effectiveness against severe disease.
Omicron: Characterised by notable immune evasion leading to greater reinfection and breakthrough cases, but vaccines still performed well against severe disease.
2025 Variants: Following the trend of immune evasion, however, current vaccines and boosters still offer strong protection against hospitalisation and death.
Symptoms
Delta: Most individuals experience high fever, shortness of breath, persistent cough, and even, at times, loss of taste or smell, with more severe symptoms in some cases.
Omicron and 2025 Variants: Symptoms are usually less severe—sore throat, fever, fatigue, runny nose, and even vague loss of taste and smell. The loss of taste and smell is more uncommon.
What does this mean for the public?
While the 2025 variants are easily spread, no evidence suggests they are more serious, as the experts have stated. Vaccination still provides the best defence. Most infections tend to be milder, particularly among the vaccinated and boosted. However, some measures are prudent, such as avoiding crowded places, wearing masks, testing when symptomatic, or exercising reasonable caution overall.
Summary of the Viruses
| Aspect | Delta (2021) | Omicron (2022–23) | 2025 Variants (NB.1.8.1, LF.7) |
|---|---|---|---|
| Transmissibility | High | Very High | Very High |
| Severity | High | Mild-moderate | Mild |
| Immune Evasion | Moderate | High | High |
| Vaccine Protection | Strong (severe) | Strong (severe) | Strong (severe) |
| Common Symptoms | Fever, cough, loss of taste/smell | Sore throat, fatigue | Sore throat, cough, mild fever |
Conclusion
The 2025 COVID-19 variants NB.1.8.1 and LF.7 are rapidly spreading, but their danger does not seem worse than Delta or other earlier strains. The focus must still be placed on surveillance of variant evolution, vaccine uptake, and adherence to public health measures to minimise severe morbidity and mortality.
Read: Is the 2025 Variant of COVID-19 More Dangerous? What Everyone Should Be Aware Of
Read more: Vaibhav Suryavanshi: The Teenage Prodigy Redefining Indian Cricket
