Health

Emerging Covid variants Stratus and Nimbus accelerate UK case rise but do not increase severity

Saturday, 4 October 2025 4:04AM UTC

As the UK faces a surge in Covid-19 cases driven by the highly contagious strains Stratus and Nimbus, health experts emphasise the importance of self-isolation and vaccination to curb transmission during the winter months, despite no evidence of increased severity.

A leading pharmacist in the UK has emphasised the importance of staying at home and resting for those who test positive for Covid-19, as infections increase driven by two new, highly contagious variants. The strains, named Stratus and Nimbus, are currently dominant in the UK, with official data showing a 22% rise in cases in the week to September 24, reaching 447 cases, alongside a modest increase in hospital admissions and deaths.

George Sandhu, Deputy Superintendent Pharmacist at Well Pharmacy, urged anyone testing positive to self-isolate in line with NHS guidance to minimise spreading the virus. He highlighted that Stratus, in particular, is spreading at an alarming rate, having mutated more quickly than previous strains and exhibiting a higher infection rate. Sandhu advised that adults should isolate for five days after testing positive, while children and young people, who tend to be infectious for a shorter period, should isolate for three days. Those who live with or care for elderly or vulnerable individuals, especially people with weakened immune systems, are advised to extend this period to ten days.

The symptomatic profile of these variants shares many hallmark Covid signs such as cough and fever, but patients affected by Stratus frequently report a hoarse throat, while those with Nimbus describe a particularly painful, “razor blade-like” sore throat. Experts caution that symptoms of these variants may easily be confused with cold or flu, underscoring the importance of testing for accurate diagnosis.

According to UK Health Security Agency (UKHSA) data, Stratus accounts for approximately 63% of current Covid cases, with Nimbus contributing around 25%. Despite their prevalence, health authorities assert that these variants do not cause more severe illness compared to previous strains. The World Health Organization has classified Stratus (officially XFG and XFG.3) as a "variant under monitoring," noting that it has contributed to about 60% of global Covid cases recently. Its rise is attributed to slightly increased transmissibility and partial evasion of existing immunity, compounded by waning population immunity and the seasonal return to indoor settings such as schools.

Government guidance reiterates the need for caution. Individuals testing positive are advised to avoid contact with others for five days, and children for three days, to reduce viral spread. For those dealing with vulnerable people, a 10-day precautionary period is recommended. In addition to isolation, practical steps such as wearing well-fitting face coverings in crowded places, frequent handwashing, and limiting contact with high-risk individuals remain key measures to control transmission.

The autumn booster vaccination programme is underway, with eligible individuals urged to receive their booster doses to strengthen immunity amid the rise in cases. While the situation bears similarities to previous autumn and winter spikes, officials emphasise that vaccination and adherence to public health advice remain the best defence against severe outcomes.

In summary, although the new Covid variants Stratus and Nimbus are driving a noticeable rise in Covid cases across the UK, current evidence does not signal increased severity. Health professionals strongly recommend following NHS guidelines for testing, isolation, and vaccination to help curtail the spread, particularly protecting those most vulnerable to serious illness during the winter months.

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Source: Noah Wire Services

More on this

https://www.yorkshirepost.co.uk/health/stay-at-home-and-rest-pharmacist-urges-people-to-follow-covid-advice-as-cases-surge-after-new-variant-5345345 - Please view link - unable to able to access data
https://www.theweek.com/health/the-new-stratus-covid-strain-and-why-its-on-the-rise - A new Covid sub-variant, nicknamed 'Stratus' (officially XFG and XFG.3), has become dominant in the UK, now accounting for a majority of new cases. It presents usual Covid symptoms such as cough, fever, and loss of taste or smell, but is particularly noted for causing a severe, razor-blade-like sore throat. Despite its rapid spread, health authorities including the UK Health Service Agency (UKHSA) assert that current vaccines remain effective, and there’s no indication Stratus leads to more severe illness than previous variants. Stratus has also been identified by the World Health Organization as a 'variant under monitoring', contributing to about 60% of global cases. Its rise is attributed to slightly increased infectivity and partial evasion of existing immunity. Experts suggest waning population immunity and the seasonal return to settings like schools are behind the recent spike in infections, with potential for further rises in October, similar to trends seen in 2024.
https://www.gov.uk/government/news/new-guidance-sets-out-how-to-live-safely-with-covid-19 - The UK government has issued new guidance on living safely with COVID-19. Individuals who test positive are advised to stay at home and avoid contact with others for five days following the positive result. Children and young people who are asymptomatic and test positive should stay at home and avoid contact with others for three days after the test. It's particularly important for those with symptoms of a respiratory infection to avoid close contact with people at higher risk of serious illness. If a person has tested positive for COVID-19, they should avoid those at higher risk for a 10-day period.
https://www.gov.uk/guidance/people-with-symptoms-of-a-respiratory-infection-including-covid-19 - This guidance provides information for individuals with symptoms of a respiratory infection, including COVID-19. If you are a close contact of someone who has tested positive, it's important to avoid contact with people at higher risk of severe illness, limit close contact with others, wear a well-fitting face covering in crowded places, and wash your hands frequently. If you develop symptoms of a respiratory infection, try to stay at home and avoid contact with other people. Children and young people who test positive should stay at home and avoid contact with others for three days after the test.
https://www.itv.com/news/2025-09-30/nimbus-and-stratus-should-i-be-worried-about-the-new-covid-variants - Two new Covid variants, Stratus (XFG) and Nimbus (NB.1.8.1), are spreading rapidly throughout the UK. While they are likely to cause only minor illnesses, health officials have urged people to be vigilant. According to the UK Health Security Agency (UKHSA), roughly 63% of monitored cases in the UK were Stratus, while 25% were Nimbus. The UKHSA noted that current data does not indicate these variants lead to more severe illness. They recommend that people with either variant should avoid contact with vulnerable people and stay home if possible.
https://www.independent.co.uk/news/uk/home-news/covid-symptoms-2025-stratus-new-variant-strain-xfg-b2832573.html - A new strain of Covid, called Stratus, is circulating in the UK, accounting for a high proportion of cases in England. The strain, officially known as XFG and XFG.3, is noted for causing a particularly hoarse voice. Despite accounting for a large proportion of new cases, experts are not concerned over the spread, noting it is normal for viruses to mutate and change. The World Health Organisation has designated XFG as a 'variant under monitoring' and has said the additional public health risk posed by XFG is evaluated as low at the global level.
https://www.nationalmedia.uk/2025/10/health-chiefs-urge-caution-as-new.html - Health officials are advising the public on how to manage symptoms and prevent spread as two new COVID-19 variants, Stratus (XFG) and Nimbus (NB.1.8.1), are fueling a rise in cases across the UK this autumn. These variants now account for almost 90% of all recorded COVID cases in the United Kingdom. The UK Health Security Agency (UKHSA) has moved to reassure the public, stating that current data does not indicate these variants lead to more severe illness. They recommend that people with either variant should avoid contact with vulnerable people and stay home if possible.

Noah Fact Check Pro

The draft above was created using the information available at the time the story first emerged. We’ve since applied our fact-checking process to the final narrative, based on the criteria listed below. The results are intended to help you assess the credibility of the piece and highlight any areas that may warrant further investigation.

Freshness check

Score: 8

Notes: The narrative is recent, published on 3rd October 2025. The Stratus and Nimbus variants have been reported since early 2025, with the earliest known reports in January 2025. The article provides updated data on case numbers and hospital admissions, indicating a high freshness score. However, the content is not entirely original, as similar information has been reported by other outlets. The narrative is based on a press release from Well Pharmacy, which typically warrants a high freshness score. No significant discrepancies in figures, dates, or quotes were found. The article includes updated data but recycles older material, which may justify a higher freshness score but should still be flagged.

Quotes check

Score: 7

Notes: The direct quote from George Sandhu, Deputy Superintendent Pharmacist at Well Pharmacy, urging individuals to isolate for five days after testing positive, appears to be original. No identical quotes were found in earlier material, suggesting potential originality. However, the phrasing and content are consistent with standard public health advice, which may indicate a lack of exclusivity.

Source reliability

Score: 9

Notes: The narrative originates from the Yorkshire Post, a reputable UK newspaper. The information is attributed to George Sandhu, Deputy Superintendent Pharmacist at Well Pharmacy, a legitimate and verifiable entity. The Well Pharmacy is a well-known UK pharmacy chain, enhancing the credibility of the information.

Plausability check

Score: 8

Notes: The claims about the Stratus and Nimbus variants are consistent with known information, including their symptoms and prevalence. The advice to self-isolate for five days aligns with current NHS guidelines. The tone and language are appropriate for the UK audience and the topic. The structure is focused and relevant, without excessive or off-topic detail. No inconsistencies or suspicious elements were identified.

Overall assessment

Verdict (FAIL, OPEN, PASS): PASS

Confidence (LOW, MEDIUM, HIGH): HIGH

Summary: The narrative is recent and provides updated information on the Stratus and Nimbus Covid variants, with no significant discrepancies or issues identified. The source is reputable, and the content is plausible and consistent with known information.

Covid-19
Variants
Public Health