A newly identified flu strain that spreads easily and causes more severe illness is driving infections this season. The strain, a mutated form of influenza A H3N2 known as subclade K, has been linked to a growing number of cases worldwide, including across the United States.

According to the World Health Organization, the K variant represents “a notable evolution in influenza A (H3N2) viruses,” prompting concerns among experts about how well this season’s flu vaccine may work against it.

Health specialists say the K variant is associated with stronger flu symptoms such as fever, chills, headaches, exhaustion, cough, sore throat, and a runny nose. A CDC report found that of the 216 influenza A(H3N2) samples collected since September 28, nearly 90 percent were identified as subclade K. As this strain continues to circulate, here is a closer look at the symptoms being reported and the areas where flu activity is currently highest.

New Flu Symptoms

Doctors say the symptoms caused by the mutated H3N2 strain closely resemble those of typical seasonal influenza A. Common symptoms include:

• Fever
• Chills
• Body aches
• Headache
• Severe fatigue
• Nasal congestion or a runny nose
• Cough

Flu symptoms often come on abruptly, Hopkins explains, describing it as a sudden, overwhelming feeling of being unwell.

The CDC notes that flu symptoms can overlap with those of COVID-19 and other respiratory viruses, making testing important. Three-in-one rapid home tests that check for influenza A, influenza B, and COVID-19 are now available, and experts advise keeping them on hand when possible. If you test positive for the flu, antiviral medications may help shorten the illness and lessen symptom severity, Hopkins adds.

Flu Shots: Where Is Subclade K Spreading In The US?

Below are the states and regions reporting the highest levels of medical visits related to flu-like illness, which may not reflect confirmed flu cases. The data reflects CDC reporting for the week ending December 25.

Very High (Level 1)

• New York City

Very High (Level 2)

• New York State

Very High (Level 3)

• New Jersey
• Rhode Island
• Louisiana
• Colorado

High (Level 1)

• Massachusetts
• Connecticut
• Michigan
• Idaho
• South Carolina

High (Level 2)

• New Mexico

High (Level 3)

• Washington, D.C.
• Maryland
• North Carolina
• Georgia

The CDC estimates that the flu has already caused at least 4.6 million illnesses, 49,000 hospitalizations, and 1,900 deaths so far this season. Health officials continue to recommend the flu vaccine as the most effective way to reduce the risk of serious illness.

Super Flu Symptoms: How to Protect Yourself From the Flu

During peak respiratory virus season, experts advise taking basic precautions to lower your risk and protect others:

• Keep vaccinations up to date.
• Get tested if symptoms appear.
• If you test positive, stay home until you are fever-free for 24 hours without medication and your symptoms are improving. If you do not have a fever, remain home for five days after symptoms begin.
• Avoid close contact with people who are sick.
• Wear a mask in crowded indoor settings.
• Wash your hands often.
• Cover your mouth and nose when coughing or sneezing.

Although many people are only now becoming aware of it, adenovirus is being widely described as a “mystery illness spreading worldwide,” and that description feels accurate when you consider how many people are reporting symptoms at the moment. Adenovirus can cause fever, a runny nose, sore throat, and stomach discomfort, which makes it difficult to distinguish from a regular cold or the so-called “super flu” that is currently circulating. If you are feeling unwell, or concerned about catching an infection just before the holiday season, Dr Deborah Lee from Dr Fox Online Pharmacy explains how to tell adenovirus apart from the common cold and from the H3N2 flu strain.

What Is Adenovirus?

Adenovirus refers to a large group of viruses that can lead to infections ranging from mild to more severe. These viruses can affect the respiratory tract, eyes, digestive system, and urinary tract, often causing symptoms that look very similar to a cold or flu.

Adenoviruses are hardy, spread mainly through respiratory droplets, and can infect people throughout the year. Children and individuals with weaker immune systems may experience more serious illness, but most people recover with rest and fluids, according to the Cleveland Clinic.

Adenovirus vs Cold: How Does Adenovirus Differ From Common Cold?

Adenovirus is one of several viruses that can trigger cold-like symptoms. It helps to think of a cold as a set of symptoms rather than a single illness, with adenovirus being just one possible cause. “Adenovirus is just one virus that can cause the common cold,” says Dr Lee. She adds that many other viruses can also be responsible, including respiratory syncytial virus (RSV), rhinoviruses, parainfluenza viruses, and coronaviruses.

Identifying the exact virus behind your cold symptoms is very difficult. “It is pretty much impossible for you or a doctor to know which virus is causing your cold symptoms,” Dr Lee explains.

Adenovirus vs Flu: How Does Adenovirus Differ From The Flu?

“The flu can be extremely unpleasant, whereas adenovirus is usually mild,” Dr Lee says when comparing the two. She explains that flu symptoms often appear suddenly, sometimes within hours, and are usually marked by a high fever and severe discomfort.

According to Dr Lee, flu symptoms can include:

• A high temperature between 38°C and 40°C
• Joint pain and muscle aches
• Headache
• Sore throat
• Blocked or stuffy nose
• Dry cough
• Extreme fatigue

In contrast, adenovirus symptoms, when they appear at all, tend to develop slowly over several days, Dr Lee notes.

Other important differences between adenovirus and flu include:

• Adenovirus infections can occur at any time of year, while flu is more common during winter
• Adenovirus frequently causes pink eye, whereas influenza may lead to red or irritated eyes but less commonly
• Adenovirus often causes digestive symptoms such as vomiting and diarrhoea, while flu can cause these but does so less often
• Adenovirus is generally less likely to cause serious complications than influenza

Adenovirus: How To Tell If You Have Adenovirus Or Cold Or Flu?

Although adenovirus and common cold symptoms often overlap, the intensity of “super flu” symptoms usually stands out. Even so, Dr Lee explains, “The only way to really know the cause of your symptoms is to have a swab taken by a medical practitioner. This may be from the nose, throat, eye, urine, or stool.”

In most cases, testing is unnecessary and unlikely to be offered. “Because the vast majority of these viral infections are mild and self-limiting, this is rarely done,” says Dr Lee. “Treatment for any cold is symptomatic only.” She adds that extra caution is needed for babies and young children, older adults, pregnant women, and people with weakened immune systems.

Tramadol: A broad review of previously published studies suggests that tramadol, a powerful opioid often prescribed for long-term pain, provides only modest pain relief for the conditions it is most commonly used to treat. The conclusions come from a combined analysis of existing research, published online in BMJ Evidence-Based Medicine.

The review also highlights a greater risk of serious side effects, including heart-related problems. In light of these findings, the researchers say tramadol’s potential harms are likely to outweigh its benefits and advise that its use should be scaled back.

Don't Miss: Sore Throat Relief At Home: 7 Remedies That Actually Help

What Is Tramadol?

Tramadol is a dual-mechanism opioid prescribed for moderate to severe pain, both short-term and long-lasting. For this reason, it features in several medical guidelines as an option for pain control, the researchers note. Prescriptions for tramadol have increased sharply over the past few years, making it one of the most widely used opioids in the United States.

This rise may be linked to the belief that tramadol causes fewer side effects and carries a lower risk of dependence than other fast-acting opioids. Although earlier systematic reviews have looked at tramadol, the researchers point out that no previous review has fully assessed both its effectiveness and safety across a wide range of chronic pain conditions.

Tramadol: Why Are Scientists Cautioning Against Tramadol Use?

According to Scitech Daily, the research team searched medical databases for randomized clinical trials published up to February 2025. These studies compared tramadol with a placebo, or dummy treatment, in people living with chronic pain, including cancer-related pain.

Nineteen clinical trials involving 6,506 participants with chronic pain met the criteria for inclusion. Five studies examined tramadol’s effect on nerve pain; nine focused on osteoarthritis; four assessed chronic lower back pain; and one looked at fibromyalgia. Eight trials also reported the rate of serious side effects during follow-up periods ranging from seven to sixteen weeks.

Don't Miss: Flu Shot: Will Getting Vaccinated Twice This Year Boost Immunity?

Statistical analysis showed that tramadol was linked to about twice the risk of harm compared with placebo. This increase was largely driven by a higher number of cardiac events, including chest pain, coronary artery disease, and congestive heart failure. Tramadol use was also associated with a greater risk of certain cancers, although the researchers describe this finding as “questionable” due to the short follow-up period.

When all trial data were pooled, tramadol treatment was also tied to a higher likelihood of less severe side effects such as nausea, dizziness, constipation, and drowsiness. The researchers acknowledge that the study outcomes carried a high risk of bias. However, they add that this likely means the benefits of tramadol may be overstated while its risks could be underestimated.

Tramadol Side Effects

According to the NHS, like most medicines, tramadol can cause side effects, although not everyone experiences them. You should speak to your doctor or pharmacist if any of the side effects listed below trouble you or persist.

• Very common side effects
• Very common side effects affect more than 1 in 10 people and include:
• feeling sick
• feeling dizzy

Tramadol: Common Side Effects

These occur in more than 1 in 100 people. There are steps that can help manage them.

• headaches
• feeling sleepy, tired, dizzy, or “spaced out”
• nausea or vomiting
• constipation
• dry mouth
• sweating
• low energy

Tramadol: Serious Side Effects

Serious side effects affect fewer than 1 in 100 people.

Call your doctor or contact 111 immediately if you:

• feel dizzy, tired, and unusually low on energy, which may signal low blood pressure
• experience hallucinations, such as seeing or hearing things that are not there
• feel confused
• feel extremely sleepy
• have difficulty passing urine or are unable to urinate

Does Tramadol Lower Blood Pressure?

Yes, tramadol can cause a drop in blood pressure, known as hypotension, particularly when standing up suddenly. This can lead to dizziness or fainting, although it is not very common. In rare cases, tramadol may also raise blood pressure, and stopping the drug suddenly can trigger a spike in blood pressure. For these reasons, anyone with concerns about blood pressure should discuss them with their doctor, according to the NHS.

Waking up with a sore, scratchy throat can feel like a dry-air problem, especially during colder months. In reality, it is often one of the first signs that your immune system has started responding to a viral infection.

What Can Cause Throat Discomfort?

Throat discomfort is often the earliest symptom because viruses tend to attach themselves to this area first, explained Benjamin C. Tweel, an assistant professor of otolaryngology at the Icahn School of Medicine at Mount Sinai, as per The Washington Post.

“The virus enters the cells that line the throat, which likely triggers an inflammatory response from the immune system,” said Tweel, who also serves as medical director for the department of otolaryngology at Mount Sinai Health System. Once the body detects the virus, lymphatic tissue at the back of the nose and throat becomes swollen and inflamed, leading to pain, experts noted.

“Sometimes your body manages to fight it off before it turns into anything major,” Mock said. In other cases, familiar upper respiratory symptoms soon follow, such as a runny nose, nasal congestion and coughing.

Don't Miss: Flu Shot: Will Getting Vaccinated Twice This Year Boost Immunity?

Home Remedies For Sore Throat

According to the Centers for Disease Control and Prevention, throat pain linked to an upper respiratory infection usually improves within about a week. Over-the-counter pain relievers like ibuprofen or naproxen can help ease discomfort and may be more effective than acetaminophen because they reduce both pain and inflammation, Tweel said. Alongside medication, certain home remedies may also provide relief. Here are some options worth trying.

Saltwater Gargle

Gargling with salt water has long been recommended for sore throats, and limited research suggests it may help. A small randomized controlled trial published in 2019 in the Journal of Complementary and Alternative Medical Research found that people with nonbacterial sore throats who used saltwater gargles reported less pain and less difficulty swallowing after one week compared with those who used a thymol-based antiseptic mouthwash.

Salt may help by reducing swelling in throat tissue, said Cameron Wick, an otologist and neurotologist at University Hospitals. “This is basic osmosis,” he explained. “Some of the fluid inside the throat tissue moves into the salt solution, which can lessen inflammation.” Saltwater gargling may also help clear away debris and viral particles, Tweel added.

While the evidence is limited, saline gargles are unlikely to cause harm, Mock said. “It might offer a small benefit, and it is generally safe.” Wick recommends mixing 1 teaspoon of salt into 8 ounces of warm water. Saltwater rinses may also help with thick mucus, nasal congestion or allergy symptoms. Wick said over-the-counter saline sprays or nasal irrigation devices can help clear nasal passages, improve breathing, hydrate tissues and reduce swelling.

Don't Miss: Adenovirus Cases Rise In UK, Health Authorities On Alert

When using nasal irrigation devices, only distilled, sterile or boiled and cooled water should be used. Tap water can contain microorganisms that are unsafe if they enter the sinuses.

Honey

Honey is known for its antibacterial properties, Wick said, and its thick texture can coat and protect irritated throat tissue. “It feels soothing on mucosal surfaces,” he explained. By forming a barrier, honey may reduce irritation from air, liquids and swallowing.

Some research supports honey for easing symptoms of upper respiratory infections, including sore throat and cough. A small study published in 2023 found that gargling with a mixture of honey and water helped reduce throat pain after tonsillectomy surgery.

Honey can also be helpful for children over the age of 1 who have sore throats or coughs. The American Academy of Pediatrics recommends honey over many over-the-counter cold medicines for young children, as those products offer limited benefit. “For kids older than 1, a teaspoon of honey or honey mixed into warm liquid can help soothe the throat and improve sleep,” Mock said. Honey should never be given to infants under 12 months due to the risk of infant botulism.

Tea

Warm tea can feel comforting on a sore throat, but not all teas are ideal during an infection. “Stick to non-caffeinated options,” Wick advised. Black teas and other strong, tannin-rich teas often contain caffeine, which can increase urine output and contribute to dehydration.

There is limited research on herbal teas for throat pain, but chamomile, ginger and turmeric are commonly recommended, Wick said.

Adding honey and lemon can enhance tea’s soothing effects. Lemon provides vitamin C, which supports immune function, and stimulates saliva production, Wick explained. Increased saliva can help thin mucus and support the many small glands beneath the throat’s surface, making it easier for the body to manage congestion.

Warm Beverages

If tea is not your preference, other warm drinks such as warm water, vegetable broth, bone broth or soup may provide similar comfort. “Warm liquids have a calming effect,” Wick said.

These beverages may also encourage better hydration, which is important for recovery. “Staying hydrated is one of the most helpful things you can do for a sore throat,” Tweel said. Dryness tends to worsen throat pain. Soup can also be soothing, as long as it does not contain ingredients that irritate the throat, Mock added.

Cool Foods

Some people find relief from cold items like ice chips or ice pops, especially when throat pain is more intense, Wick said. After tonsil removal surgery, children are often encouraged to eat ice cream or popsicles because cold temperatures can calm pain-sensitive nerve endings.

There is little research specifically on cold foods for sore throats caused by infections, but cooling therapies have been shown to reduce throat discomfort after medical procedures such as surgery or intubation.

Using A Humidifier

Dry air can worsen irritation in the nose, mouth and throat. “This helps explain why people often feel worse after flying,” Tweel said. A cool-mist humidifier or vaporizer can reduce dryness and ease scratchiness.

However, these devices must be cleaned carefully. “I personally avoid them because proper sanitation can be difficult,” Tweel said. Mold and bacteria can grow in humidifiers, and inhaling contaminated mist may increase the risk of illness.

The CDC advises cleaning humidifiers according to manufacturer guidelines, emptying water tanks daily, and using distilled or boiled and cooled water to reduce microbial growth.

If maintaining a humidifier feels overwhelming, steam from a hot shower or from a cup of hot tea or boiling water may offer similar benefits, Tweel said.

Lozenges

For adults, lozenges or cough drops can stimulate saliva production, which helps combat dryness, Tweel said. “A lot of throat soreness comes from being dry or dehydrated,” he explained. Increasing moisture can make a noticeable difference.

There are many lozenge options available, and choosing what feels soothing is reasonable. Some people prefer lozenges with menthol or eucalyptus for their cooling sensation. Lozenges and cough drops should not be given to children under 4 years old due to choking risks.

When To See Your Doctor For A Sore Throat

Most sore throats improve after a few days, Mock said, often followed by nasal symptoms and then a chest cough. “That pattern is typical for a viral upper respiratory infection,” she said. As long as symptoms are improving and not worsening, the illness usually resolves within one to two weeks.

Medical care may be needed in certain situations. You should contact your primary care provider if throat pain is accompanied by fever, severe pain, difficulty breathing or swallowing, white patches at the back of the throat, or noticeable differences in tonsil size, Wick said. These signs may point to a bacterial infection such as strep throat, which may require antibiotics.

Persistent throat pain should also be evaluated. “A severe sore throat lasting more than seven days is not normal,” Mock said. “By that point, it should be improving.”