Concerns over new Covid-19 variants are once again making headlines across the globe. In recent weeks, the United States and United Kingdom reported a sharp rise in Covid-positive hospital patients, sparking fears of another wave of infections.
Two new variants-Stratus (XFG) and NB.1.8.1 (Nimbus)-have surfaced internationally. Both are recombinant strains, meaning they carry genetic material from earlier versions of the virus but with mutations that could affect how easily Covid-19 spreads or sidesteps immunity.
South Africa has not yet detected these strains, but health officials are urging vigilance. The country has weathered multiple waves since 2020, and lessons from abroad show how quickly Covid-19 can resurface.
The Stratus Variant: Why It’s Raising Concern
The Stratus variant (XFG) emerged when two lineages-F.7 and LP.8.1.2-combined inside the body of a person infected with both strains at once. That “mix and match” genetic process created a new variant carrying mutations linked to immune evasion.
In other words, Stratus has the potential to dodge some of the body’s defences developed through vaccination or prior infection.
The UK has already seen the effects. According to the UK Health Security Agency (UKHSA), hospital positivity rates climbed from 5.8% on 26 July to 7.6% by 10 August-a 31% surge in just 15 days.
To put it plainly: on 26 July, six out of every 100 hospital patients with flu-like symptoms tested positive for Covid-19. Just over two weeks later, that number rose to eight. While the percentages may seem small, the speed of the increase has alarmed health professionals.
Nimbus: A Slow but Steady Riser
Alongside Stratus, researchers are tracking NB.1.8.1 (Nimbus), a descendant of the Omicron lineage. First detected in Asia in January 2025, Nimbus spread widely enough that the World Health Organization (WHO) classified it as a Variant Under Monitoring (VUM) in May.
Global data shows its steady rise: from 2.5% of uploaded Covid-19 sequences in March 2025 to 10.7% by late April. By mid-May, Nimbus had already reached 22 countries, particularly across Asia.
Like Stratus, Nimbus carries mutations in its spike protein that increase transmissibility and allow partial immune evasion. However, WHO researchers stress that current evidence does not show Nimbus causing more severe disease than earlier variants. Covid-19 vaccines are still expected to protect against serious illness and hospitalisation.
What This Means for South Africa
For South Africans, the outlook remains cautiously reassuring. National surveillance data confirms that as of June 2025, neither Stratus nor Nimbus has been detected in the country. Syndromic surveillance programmes, which track respiratory illness trends, continue to report low Covid-19 infection rates.
Immunity levels in the population also provide a buffer. Years of vaccination campaigns and prior waves of infection mean that most South Africans now carry some level of protection.
Johannesburg infectious disease specialist Dr. Kabelo Maseko put it plainly:
“South Africa’s immunity wall is strong. New variants may cause short-term spikes in cases, but we don’t expect the same scale of severe illness and hospitalisations we saw during earlier waves.”
Lessons from Abroad
Even with reassurance at home, spikes in the UK and US serve as warnings. Covid-19 can rebound quickly when conditions allow. South Africa’s healthcare system-already stretched by staff shortages, water cuts, and vaccination campaigns for other illnesses like measles-cannot afford to be caught unprepared.
The Network for Genomic Surveillance in South Africa (NGS-SA) continues to sequence local samples to detect new variants early. While testing has dropped since the peak of the pandemic, genomic surveillance remains a vital early-warning system.
How the Public Can Stay Protected
Health experts continue to highlight basic preventive measures:
- Wash hands often and practise good hygiene.
- Cover coughs and sneezes with an elbow or tissue.
- Stay home when sick and avoid contact with vulnerable people.
- Wear a mask in crowded indoor spaces, especially around elderly or chronically ill individuals.
- Keep vaccinations up to date, as vaccines remain highly effective against severe disease.
Public health campaigners warn against complacency. Nomvula Khumalo, a Gauteng health activist, stressed:
“Covid-19 hasn’t disappeared. We’re not in crisis, but we must still protect ourselves and the vulnerable-especially the elderly and immunocompromised.”
Looking Ahead
The appearance of Stratus and Nimbus is a reminder that COVID-19 continues to mutate. For now, the risk to South Africa is low, and vaccines remain effective. But monitoring and everyday caution remain key to ensuring the country isn’t blindsided by another wave.
As WHO officials have warned, complacency could undo years of progress. The virus has slowed-but it has not stopped evolving.
Final Word
South Africans can breathe a little easier knowing infection rates remain low and no new variants have been detected locally. But the rapid increases abroad show just how fast conditions can change.
By practising simple prevention and staying alert to official updates, Gauteng residents-and South Africans at large-can face the future prepared, protected, and resilient against whatever the next chapter of Covid-19 brings.
