COVID's Newest Variants 'Nimbus' and 'Stratus' Spread 2.5X Faster - Two New Symptoms Emerge (Credits: Pexels)
While India’s latest COVID-19 caseload drops to the 6,400 mark, the country is facing the insurgence of two different variants, NB.1.8.1 and XFG, that are spreading rapidly.
Earlier this week, the caseload touched the 7,400 infections mark and sparked fears of another major wave, but the recent dip in numbers has suggested that it may have been more of a seasonal uptick than a sustained surge. Medical experts are also mentioning that this may be a ‘mini-wave’ or seasonal short-term rise as opposed to a full-blown resurgence of the virus.
But, apart from the active infection cases, it is important to take precautions on our own as well. Unlike the Delta or early Omicron surges, this phase will not be putting pressure on the hospitals as ICU occupancy remains almost negligible.
While experts say that this may be a sign of growing population-level immunity, it is important to know all about the Nimbus or Stratus variant so one can stay safe.
Symptoms of Nimbus and Stratus COVID-19 variants
COVID-19 variants NB.1.8.1, aka Nimbus, and XFG, aka Stratus, come with a distinctive symptom: a sharp, stabbing pain in the back of your throat when you swallow. This is called the “razor blade sensation.” Rest, fluids and painkillers are the best remedies for this painful symptom. Alongside this, persistent fatigue, mild fever, nasal congestion and muscle aches are also symptoms of the Nimbus variant.
In addition to this, the new COVID-19 variants are also causing gastrointestinal symptoms such as vomiting, nausea, heartburn, bloating, diarrhoea, bloating, constipation, and stomach pain.
They may be spreading fast, but they aren’t riskier
After being identified in early January 2025, NB.1.8.1 has quickly made its way to most parts of Asia, accounting for 11% of sequenced cases by late April 2025. While this is rapid as compared to the previous and co-circulating variants, there are no reports that suggest that NB.1.8.1 is linked to severe illness compared to the same.
WHO also noted that XFG was spreading even faster than NB.1.8.1, but similar to the latter, there is no evidence to suggest that it is associated with more severe disease at the current time.
Nimbus sticks to the cells and infects them really fast
Studies have shown that NB.1.8.1 strongly binds itself to the ACE2 receptor that SARS-CoV-2 uses to enter human cells, and this happens more strongly than the XFG variant. It also suggests strong infectivity in lab-grown cells, and this shows that it is very well-equipped to spread. The infectivity of NB.1.8.1 is 2.5x higher than that of LP.8.1 (currently the most prevalent COVID-19 variant worldwide).
So, Nimbus doesn’t evade the immune system but infects people more efficiently.
Stratus is great at evading the immune system
XFG’s mutations evade antibodies that target common spots on the spike protein. But this one doesn’t bind to the human ACE2 receptor, so it is not as good at infecting cells or spreading on its own (unless it picks up other mutations).
COVID-19 vaccines are effective against them both
COVID-19 vaccines have proven to be effective in protecting against both the Nimbus and Stratus variants. Staying up to date with booster doses has also been suggested by medical experts as this enhances protection and keeps one safe. Doctors have also suggested that the COVID-19 vaccination remains one of the strongest tools to safeguard yourself and the community against both the NB.1.8.1 and XFG virus strains.
