Nearly five years after COVID-19 first upended daily life, the virus continues to evolve. The latest variant gaining attention is called Stratus — a name already making its way through news headlines, social media chatter, and public health briefings. First flagged in multiple U.S. states and several countries in late 2024, Stratus is now showing steady growth in reported cases across the globe.

What makes it different? Scientists say Stratus belongs to the Omicron family, but carries a distinct set of mutations that may affect how it spreads and the symptoms it causes. While early data is still emerging, its trajectory has many experts urging caution without panic.

Stratus (officially XFG) popped up on researchers’ radar in early 2025 as a genetic recombination of two prior COVID-19 strains—LF.7 and LP.8.1.2. By late spring, it accounted for nearly 23% of global cases, and hovered at around 14% in the US. In England, its rapid climb—from 10% to 40% prevalence in mere weeks—warranted media nicknames like “Frankenstein variant” and set off alarm bells about just how fast it can spread. The World Health Organization currently lists Stratus as a variant under monitoring, citing its concerning immune-escape mutations but noting the overall public health risk remains low for now.

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How Stratus Is Spreading?

Stratus’ dominance across regions stems from its transmissibility, not its severity. Four key mutations in the spike protein may help it evade immunity—whether from past infection or vaccination—but there’s no sign yet that it causes more severe disease.

Data from the U.S. Centers for Disease Control and Prevention (CDC) shows Stratus now accounts for a growing percentage of new COVID cases nationwide, particularly in urban centers with high travel activity. Similar trends are being reported in parts of Europe, Asia, and Australia.

Unlike earlier variants that surged sharply, Stratus appears to be building momentum more gradually — but steadily. This slower curve may allow it to spread under the radar for longer, especially in areas where testing and genomic sequencing have scaled back since the height of the pandemic.

What Are Stratus Symptoms You Should Know

If you’ve been keeping track, sore throats—and not just any sore throat—have become Stratus’ odd signature. People describe it as scratchy or raspy tones, easily mistaken for allergies or seasonal laryngitis. According to early clinical reports, the most common Stratus symptoms include:

• Persistent sore throat or hoarseness
• Headaches that last several days
• Nasal congestion and mild fever
• Fatigue that lingers beyond the acute phase

Some patients also report changes in smell or taste, but less frequently than with earlier variants. Shortness of breath and chest discomfort remain uncommon in vaccinated individuals but can occur in higher-risk groups.

Doctors stress that the full symptom spectrum may become clearer as more data is collected over the coming months.

COVID now spreads faster than before. According to updated medical data, incubation with Omicron-like variants—including Stratus—is often around 3 to 4 days—shorter than earlier strains’ 5–7 days. That means the usual advice is still relevant:

• If symptoms begin, test early—but not too early, since antigen kits may fail at onset.
• If negative, test again in 24–48 hours if symptoms persist.
• Most adults can end isolation after 5 to 7 days, provided symptoms are improving and any fever has resolved 24 hours without medication.

Expired or faulty tests? Double-check the control line on your test. If it doesn’t appear, the kit may be invalid—even if unused

Why New Variants Keep Appearing?

Viruses mutate — it’s part of their survival strategy. Each time SARS-CoV-2 infects someone, it makes copies of itself. Occasionally, those copies contain genetic changes that give the virus an advantage, such as spreading more efficiently or dodging parts of our immune response.

For Stratus, researchers are still analyzing whether its mutations make it more transmissible or better at evading immunity from vaccines or past infections. What’s clear is that population immunity, while strong, is not absolute — especially as antibody levels naturally wane over time.

Current COVID vaccines, including updated boosters targeting recent Omicron strains, are still expected to offer protection against severe illness from Stratus. However, breakthrough infections are possible, particularly in people who haven’t had a booster in the last 6–12 months.

Public health agencies continue to recommend boosters for older adults, people with weakened immune systems, and those working in high-exposure settings. Whether a Stratus-specific vaccine update will be needed remains to be seen.

Is Preventing Spread in 2025 A Reality?

We’re no longer in the emergency stage of the pandemic, but familiar prevention strategies still matter:

• Staying home if you’re sick
• Masking in crowded indoor spaces during surges
• Testing before visiting vulnerable individuals
• Keeping up to date on vaccinations

With reduced restrictions and increased global mobility, even moderate increases in transmission can ripple quickly through communities — especially during cold and flu season.

Researchers are tracking whether Stratus leads to more reinfections, if its symptoms last longer, and whether it’s linked to post-COVID complications like long COVID. Hospitals are monitoring for any shifts in admission patterns, particularly among children and older adults.

There’s also a focus on transparency: experts say real-time sharing of data across countries is essential for staying ahead of variant-driven waves.

Stratus isn’t dramatically different—no skyrocketed hospitalizations, no alarming new symptom profiles. But it does remind us that SARS-CoV-2 is still evolving, still engaging our resilience and still requiring vigilance.

You don’t need to panic. But staying informed, testing responsibly, masking when needed, and keeping vaccinations up to date that’s how we stay ahead of the next wave.

Adenovirus, or what some people are calling the mystery disease is going to be the next worry in the UK, after superflu had already grappled the healthcare system. Along with H3N2 and its variant superclade K, people are now worrying about this mystery disease.

Adenovirus is highly contagious and causes mild cold or flu-like symptoms, though severe cases could lead to stomach flu and vomiting. Many describe this virus as 'heartier' than others. The reason is that the virus can survive longer on surfaces and even resist the common disinfectants used. This is what makes it highly transmissible.

Is There Any Treatment For Adenovirus?

As of now, there is no treatment for adenovirus, it could however be managed and monitored. What helps is regular handwashing and thorough cleaning of surfaces.

The good news is that cases of adenovirus are actually dropping in the UK, as confirmed lab reports. The cases last week were 1.2 per cent, whereas the week prior, it was at 1.7 per cent, as also reported by the Independent.

What Are The Symptoms Of Adenovirus?

While a lot of the symptoms mimics of those in flu or COVID, including shortness of breath, a sore throat and or a runny nose. However, there are certain unique symptoms of adenovirus that include:

• Diarrhea
• Pink Eye or conjunctivitis
• Ear infection or otitis media
• Swollen lymph nodes
• Pneumonia
• Stomach pain
• Nausea
• Vomiting

Other rare symptoms could also include impact on your bladder or nervous system. As viruses in your bladder can also cause urinary tract infections, and the same virus in your nervous system can cause condition that can affect your brain. These conditions also include encephalitis and meningitis.

The symptoms usually start to subside within two days, however, if the symptoms stay even after three days without any relief, it might be a red flag. The best thing to do during such a situation is to go consult your GP.

Also Read: Unique Symptoms Of Mysterious Adenovirus And How Long Infection Now Last

Is Adenovirus Spreading Faster Than Flu and Covid?

Experts have noted that due to its ability to stay longer in the environment and being highly transmissible, it is in fact, spreading faster than flu and COVID. Eric Sachinwalla, Jefferson Health's medical director said that this virus is still unfamiliar and thus not much can actually be done to treat adenovirus. Speaking to PhillyMad, he said, "It is pretty contagious because it is heartier than other viruses - soap and water, or everyday disinfectant, won't kill it, so it tends to live in the environment longer."

What Are The Ways To Stay Safe From Adenovirus?

Since adenovirus spreads through close contact and is resistant to many everyday disinfectants, hygiene remains the key. The best way to stay safe is by avoiding close contact, especially with those who are unwell. You may also keep an eye on your symptoms, including your body temperature and take steps to prevent the virus from spreading by taking precautions, as well as getting the flu jab.

The World Health Organization (WHO) on December 24 prequalified two rapid antigen diagnostic tests (Ag-RDTs) for SARS-CoV-2. This virus is known to have caused COVID-19. As per the WHO, these two tests are called SD Biosensor STANDARD Q COVID-19 Ag Test and the ACON Biotech Flowflex SARS-CoV-2 Antigen Rapid Test (Self-Testing).

At first these tests got temporary emergency approval from the WHO during the pandemic. This was done so the countries could start using them quickly even though long-term data was limited. This emergency approval helped the tests reach over 100 countries when they were urgently needed.

What Has Changed Now?

The WHO has now given these tests full prequalification, which means it has a stronger and long-term approval. This means that the WHO has thoroughly checked and confirmed that the tests consistently meet global standards for quality, safety, and accuracy.

Why Does This Matter?

• The tests can now be officially bought and used by global organizations and governments
• They can be included in bulk purchasing to lower prices and increase supply
• This makes reliable COVID-19 testing more affordable and accessible, especially in low-and middle-income countries

COVID-19 Is Far From Being Over

Even though WHO officially ended COVID-19 emergency phase over two years ago, the virus is still circulating globally. In fact, this year, we have seen variants of COVID-19 circulating around, causing the most unique symptoms, including razor-blade like throat. Variants like JN.1, Stratus, Nimbus, LP8.1, and BA.3.2 were all that we saw in 2025.

While the good news is that infection levels are relatively stable, but the virus has not completely disappeared and testing is still necessary, especially in poorer countries.

Many low-income countries do not have easy access to labs or expensive PCR testing. So there is still a need for a strong, but cheaper and reliable way to detect COVID-19, and these tests may as well do that.

Why Rapid Antigen Test Matters

• Give results in 15–30 minutes
• Cost less than PCR tests
• Don’t require labs or specialized equipment
• This means they can be used in small clinics, community centers, mobile vans, or remote areas, where lab testing isn’t practical.

However, it is important to note that rapid antigen tests are not replacement for PCR tests. They simply complement the PCR tests by allowing faster, on-the-spot decisions, especially when the lab capacity is limited.

What Makes It Essential Today?

Rapid antigen tests could help with spotting and stopping local outbreaks quickly, protecting high-risk people and healthcare workers, and staying prepared for future respiratory pandemics.

The WHO is also pushing for decentralized, quality-checked testing as part of universal healthcare and global health security, so countries aren’t caught unprepared when the next outbreak happens.

When Is It A Right Time To Get Yourself Checked For COVID-19?

If you notice these following symptoms as noted by the Centers for Disease Control and Prevention (CDC), it is best that you get yourself a COVID-19 test:

• Fever or chills
• Cough
• Shortness of breath or difficulty breathing
• Sore throat
• Congestion or runny nose
• New loss of taste or smell
• Fatigue
• Muscle or body aches

As Delhi's air quality levels and pollution continues to worsen, and people struggle to breathe, countries like Singapore, the United Kingdom, and Canada issued advisories for their citizens travelling to the capital city. However, the capital city's crisis continues to remain ignore, though CM Rekha Gupta did hold a review meeting on the same on Monday, with a follow-up scheduled on Thursday.

Singapore Travel Advisory On Delhi's Air Pollution

Singapore High Commission issued an advisory, which stated:

On 13 December 2025: The Indian Central Pollution Control Board invoked Stage 4, the highest level, of the Graded Response Action Plan (GRAP) in the Delhi National Capital Region. Under GRAP 4, construction and industrial activities are heavily restricted, and schools and offices are encouraged to shift to hybrid format. The Delhi authorities have urged residents to stay indoors, especially children and those with respiratory or cardiac ailments, and to use masks if stepping out. In this regard, the High Commission urges Singapore nationals in the Delhi National Capital Region to pay heed to this advice.

We also note that given the low visibility, flights to and from the Delhi National Capital Region are likely to be affected. The Indira Gandhi International Airport and several airlines have issued advisories. Travellers should take note of this, and check with the respective airlines for updates.

UK And Canada Too Issue Advisories On Delhi Pollution And Its Impact On People

UK's Foreign, Commonwealth & Development Office (FCDO) warned that air pollution could lead to serious health threats for those living in northern India, especially between the months of October and February. The UK advisory also stressed on the health of pregnant women and people with any heart or respiratory. The advisory noted that they must seek medical advice before travelling to India.

The statement read: Children, the elderly and those with pre-existing medical conditions may be especially affected. If you’re pregnant or have a respiratory or heart condition you may wish to consult a medical practitioner before you travel.

Canada too issued a similar notice, advising, especially those who are already struggling with respiratory issues and to continuously monitor air quality levels. The notice also highlighted the pollution that is caused by fog and smoke trends that are increasing in urban areas like Delhi, especially during the winters.

The advisory read: Smoke haze and other types of air pollution can be extremely hazardous in urban areas and cities such as Delhi. It’s typically at its worst in winter. In rural areas, air quality can be affected by agricultural burning. Dust storms also occur across northern India. Monitor air pollution levels, which change quickly, especially if you suffer from respiratory ailments or have pre-existing medical conditions.

As of today, Delhi's air quality remained in "very poor" category, and the AQI stood at 342 at 8am, as per the Central Pollution Control Board. The 24-hour average AQI was logged at 412 under the "severe" category on Tuesday evening when Delhi's quality peaked to record the fourth severe air day in the month of December.