Covid-19: Discussion on two variants of Corona NIMBUS and STRATUS, has a new variant arrived again?

For more than a month now, the outbreak of coronavirus has been seen in many countries of the world including India. This new wave which started from Hong Kong and Singapore in May started increasing rapidly in India as well. In just three weeks, the active cases in the country had increased to more than 7400, however, a decline in infection cases has been seen for the last two-three days.

More than 1200 people have recovered from the infection in the last one day, although three more deaths have been recorded. On June 15 (Sunday), there were a total of 7383 active cases, which came down to 7264 on the next day i.e. June 16. There has been a further decline on June 17 when the total active cases became 6836. That is, the decrease in infection cases is continuing.

Health experts say that even though the pace of corona has decreased in the country, it is still important to remain cautious about the risks of infection. Some variants of coronavirus spread in India are raising serious concerns in many other countries, so do not make the mistake of taking coronavirus lightly.

Two variants Nimbus and Stratus

There is a lot of discussion these days about two variants of corona, Nimbus and Stratus. Some reports claim that the infectiousness rate of these variants can be up to two and a half times higher than the previous variants of Omicron. That is, in the population in which these variants start increasing, there may be a risk of rapid increase in infection among people.

Are there any new variants, about which all people need to be alert? Let us understand this in detail.

Are there any new variants?

A look at the medical reports shows that Nimbus and Stratus are not new variants, but are nicknames for the NB.1.8.1 and XFG variants that are spreading rapidly in India. The World Health Organization (WHO) has currently placed six coronavirus variants as ‘variants under monitoring’ – which means that they may require priority attention and tracking by health officials due to their increasing spread and potential health risks.

NB.1.8.1 and XFG are also among them. NB.1.8.1 has been informally nicknamed “Nimbus”, while XFG is being called Stratus.

Stratus is considered to be more infectious.

In its latest update on 23 May 2025, WHO stated that initial research and evidence on NB.1.8.1 suggests that NB.1.8.1 is a form of the Omicron variant, which is not as effective and severe. This variant does have a higher infectious rate but does not pose any additional public health risk.

At the same time, the Stratus or XFG variant was first detected in Canada and has rapidly affected the global population. By the end of May, it had 25% cases in Europe, while NB.1.8.1 cases were 9%. It is also spreading in India, where there were 206 active cases of coronavirus till June 11, which increased to 7400 by June 15. However, now it is continuously decreasing.