With temperatures dipping and winter taking hold, the flu season has come in strong, affecting millions of people across the United States. The Centers for Disease Control and Prevention reported that recent data indicate widespread flu activity, with 40 states reporting high or very high levels of flu-like illness. While this season's flu is not record-breaking, it is another reminder of the difficulties in dealing with respiratory diseases during the colder months.

Flu is just one piece of what experts have coined the "quad-demic," which includes influenza, COVID-19, respiratory syncytial virus (RSV), and other viral infections. Each of these illnesses presents overlapping symptoms such as fever, cough, and fatigue, making diagnosis a complex process. Among them, influenza remains the most significant contributor to hospitalizations, with the CDC estimating over 5.3 million flu illnesses, 63,000 hospitalizations, and 2,700 deaths so far this season.

Even as the flu season continues to impose a heavy burden, RSV is particularly threatening to infants and the elderly, while COVID-19 continues to impact vulnerable populations. The spread of norovirus, a virulent stomach bug, and sporadic cases of bird flu have added to healthcare pressures this winter.

Impact of Flu Across the U.S.

Flu activity is most intense in the South, Southwest, and Western states, with comparatively lower rates in New England and the northern Great Plains. Hospitalizations from flu cases are straining healthcare systems, echoing the challenges seen during the peak of the COVID-19 pandemic.

In England, flu-related hospital admissions have remained significant, with thousands of daily cases reported in late December. While this year's numbers are slightly lower than the previous season, the flu’s persistence underscores its cyclical and often unpredictable nature.

How Flu Differs from Past Seasons

The 2022-23 flu season was the first major resurgence of influenza since the start of the COVID-19 pandemic, killing more than 14,500 people. This year's flu season is similar in some ways but differs in intensity by region and population. Children, older adults, and those with pre-existing health conditions are at the greatest risk.

What's Fueling the Flu Surge?

Several factors come together to create the spread of flu during the winter months. Low humidity and increased time spent indoors along with close physical contact are perfect settings for respiratory viruses. Furthermore, the holiday gathering season overlaps the peak flu season, which combines to create an ideal situation for transmission.

Health care providers report an ongoing stream of patients with flu-like symptoms. It is also observed that the flu strains that have dominated this season do not indicate a clear dominant variant, which can influence vaccine efficacy and treatment approaches.

Masks are still very useful, especially in crowded indoor settings. Such preventive measures may help reduce not only the spread of flu but also of other respiratory viruses.

Beyond Flu Are there Other Viruses to Watch For?

While flu is often in the news, other diseases are also taking their toll. RSV remains a problem for susceptible populations, and norovirus outbreaks are an ongoing threat, although these tend to be scattered. The public health community is also tracking avian influenza (H5N1), but the threat to humans remains low and largely associated with direct contact with infected animals.

How to Prepare for the Flu Season Ahead

Flu season is a periodic problem, but it also provides an opportunity for public health preparedness. Vaccine efforts, education, and proper medical care within a timely frame reduce the impact of the season to a great extent. As the hospitals deal with the load of multiple respiratory infections, individuals should take responsibility for their health and make a contribution toward preventing the infection in the general population.

Practical Tips to Fight Flu

While it is impossible to completely avoid getting ill, these measures can help you survive flu season with minimal risks:

- Wash your hands often and disinfect high-touch surfaces to reduce the spread of germs.

- Stay hydrated, eat nutrient-rich foods, exercise, and get enough rest to boost your immunity.

- Isolating yourself when you are sick will prevent the spread of illness to others.

It helps keep the indoor air at 40–50% relative humidity and keeps your respiratory system healthy. Annual flu vaccines are still one of the best preventive measures.

If you take precautions and follow preventive measures, you are set to have less of those illnesses and a healthier winter. It is possible to manage flu season by following individual efforts with community health strategies meant to protect both personal and public well-being.

The so-called “mystery virus” behind lingering sore throats, blocked noses filled with mucus, and days of exhaustion is actually well known to doctors. According to Eric Sachinwalla, medical director of infection prevention and control at Jefferson Health, the culprit is adenovirus.

What makes this virus particularly difficult to control is how tough it is. Adenovirus can survive soap and water, withstand many everyday disinfectants, and linger on contaminated surfaces for long stretches of time. Below is what experts know so far about this fast-spreading infection.

What Is Adenovirus?

Adenovirus refers to a group of common viruses that usually trigger cold- or flu-like illness. It spreads easily because it is far more resilient than many other viruses. Ordinary soap, water, and standard disinfectants do not reliably destroy it, allowing it to persist in the environment. As a result, infections often cluster in places where people spend time close together, such as daycares and military barracks. The virus spreads through the respiratory tract, can be shed in stool, and can survive for some time on contaminated surfaces, according to the CDC.

Adenovirus: What Are The Symptoms Of Adenovirus?

“Adenovirus is a typical virus that causes common cold or flu-like symptoms,” says Dr Deborah Lee at Dr Fox Online Pharmacy. That does not mean adenovirus is the same as a cold. Instead, adenovirus is one of many germs that can cause cold-like illness. A simple way to think about it is that a “cold” describes the symptoms, while adenovirus is one specific virus that can lead to them.

Symptoms can vary depending on the subtype involved. While there are more than 100 known subtypes, only 49 infect humans. Dr Lee notes that people may experience any of the following:

• Fever
• Runny nose
• Sore throat
• Swollen cervical lymph nodes in the neck
• Cough
• Shortness of breath
• Conjunctivitis
• Ear pain
• Diarrhoea
• Vomiting
• Stomach pain
• Urinary tract infection

Adenovirus? Is It Contagious?

“Adenovirus infection is highly contagious,” Dr Lee explains. “It spreads by breathing in infected droplets, by touching the virus and then rubbing the eyes, or through the faecal-oral route, often due to poor hand hygiene after using the toilet.”

She adds that the virus spreads quickly in crowded settings where people are in close contact. To eliminate adenovirus from surfaces, Dr Lee recommends stronger cleaning agents such as bleach-based solutions or hydrogen peroxide. “The virus is resistant to soap and many commonly used cleaners,” she says.

To reduce the risk of catching adenovirus or other respiratory infections currently circulating, Dr Lee advises staying away from people who are unwell. She also suggests the following precautions:

• Avoid touching your face and nose
• Use a clean tissue to blow your nose and dispose of it immediately
• Wash your hands often with soap and warm water, then dry them thoroughly, especially after using the toilet or changing nappies
• Clean children’s toys regularly
• Disinfect worktops, changing areas, toilets, and bathrooms
• Avoid sharing cups, plates, food, or towels
• Wear a mask if you need to go out while unwell
• Keep windows open and ensure rooms and workspaces are well ventilated.

As we soon step into 2026, it is time to look back at which diseases took over the world in 2025. These diseases evolved throughout the year, and led to complex challenges. Here, we explore the top 5 health crisis in 2025.

Infectious Diseases, Outbreaks, and COVID-19

This year, COVID-19 continued to make headlines, along with COVID, flu and measles too continued to infect people. In fact, new variants of COVID and flu have circulated across the world, leading to new kinds of symptoms, including razor-blade like throats in COVID-19. Influenza too surged up across US, UK, and Canada, with hospitalization rates going up. A new subclade K strain is seen responsible for this surge. Measles, too is a highly contagious, however, vaccine-preventable respiratory virus resurged this year, and this disease, which was once eliminated from the US, has come back due to lower rates of vaccination.

Tuberculosis Outbreak

A tuberculosis outbreak in the Kansas City metro area resulted in dozens of cases. This has led to two deaths, as reported by the Kansas Department of Health and Environment (KDHE). In fact, Michael A Bernstein, MD, director of pulmonary and critical care at Stamford Health said that many people assume that TB is rare and no longer a concern, however, it still remains common.

Also Read: Top 5 Infectious Diseases That Disrupted Healthcare System Worldwide In 2025

Bird Flu

In the US, the first death from bird flu was reported by the Louisiana Department of Health. The Centers for Disease Control and Prevention (CDC) reported that the individual was older than 65 years and had underlying medical conditions. That person developed severe illness and was hospitalized following the exposure to a noncommercial backyard flock and wild word. In fact, new studies have shown that bird flu viruses could have a potential risk for humans and may become next pandemic. This comes from two different studies, one done by the universities of Cambridge and Glasgow that show how avian flu strains are multiplying even when the body temperatures could hinder viruses. Whereas, another important study led by Indian scientists, by Philip Cherian and Gautam Menon of Ashoka University, published in BMC Public Health predict if H5N1 or the bird flu virus, could start spreading among humans.

Antimicrobial Resistance (AMR)

In 2025, AMR has worsened and the resistance has risen over 40% of monitored pathogen-antibiotic pairs between 2018-2023. Due to the resistance, common infections become harder to treat, especially in regions like Southeast Asia, with India facing high rates. The World Health Organization (WHO) report notes that AMR is a growing threat to global health, and draws on more than 23 million bacteriologically confirmed cases of bloodstream infections, urinary tract infections, gastrointestinal infections, and urogenital gonorrhoea.

Non Communicable Diseases or NCDs

NCDs like heart disease, cancer, diabetes, and respiratory illnesses remained a persistent global health challenge in 2025. Trends to showed a continued rise driven by unhealthy lifestyles, which included processed food, inactivity, tobacco or alcohol, and urbanization.

Dozens of norovirus outbreaks have been recorded nationwide over the past few weeks, and as people deal with intense vomiting, diarrhea, and other uncomfortable or even risky symptoms, a common question keeps coming up: why is there still no vaccine for such a widespread infection.

The Centers for Disease Control and Prevention (CDC) says norovirus cases are increasing toward the end of 2025, with higher activity reported in both the US and the UK. Health officials note that a new, highly infectious strain known as GII.17 is partly driving this rise. Because many people have little or no immunity to it, outbreaks are being seen more often in schools and shared public spaces. While overall case numbers remain within typical seasonal ranges, recent weeks have shown a clear upward trend.

What Is Norovirus?

Norovirus is an extremely contagious virus that leads to gastroenteritis. It commonly causes symptoms such as vomiting, diarrhea, nausea, and stomach cramps, and may also bring fever and body aches. It is often referred to as the ‘stomach flu,’ though it has no connection to influenza.

The virus spreads quickly through contaminated food or water, shared surfaces, or direct contact with an infected person’s vomit or stool. Crowded settings like cruise ships are especially vulnerable. Most people recover within one to three days with rest and enough fluids, according to the CDC.

Norovirus Symptoms 2025

Norovirus usually comes on suddenly, causing vomiting, watery diarrhea, nausea, and abdominal pain. Fever, headaches, and body aches are also common. Symptoms typically appear 12 to 48 hours after exposure and last for one to three days. Because it spreads so easily, infections can move fast through families and communities.

While most cases improve on their own, dehydration is a concern, so warning signs such as intense thirst or reduced urination should not be ignored, as noted by the Cleveland Clinic.

Do We Have A Norovirus Vaccine?

At present, there is no widely available vaccine for norovirus. That said, research has made meaningful strides. Experimental oral vaccines have shown encouraging results in clinical studies, suggesting they may offer protection against multiple fast-changing strains and help reduce how much virus an infected person sheds. Scientists are hopeful that an effective, broadly protective vaccine may become available in the coming years, according to the National Institutes of Health.

Why Don’t We Have a Norovirus Vaccine Yet?

Developing a vaccine for norovirus has proven especially difficult, largely because of how quickly the virus changes. “It really is evolving extremely rapidly, and that’s a big problem,” Patricia Foster, PhD, professor emerita of biology at Indiana University Bloomington, told Health.

Norovirus also exists in dozens of subtypes, with several dominant strains circulating at any given time. This is why people can catch norovirus more than once in their lives. Even if immunity develops against one strain, either after infection or through vaccination, another strain can still cause illness. Centers for Disease Control and Prevention. About norovirus.

Norovirus: Multiple Vaccines Are In The Works

Despite these obstacles, vaccine research is moving forward. Progress has accelerated in part because of newer technologies developed over the past decade. In 2016, Mary Estes, PhD, a researcher at Baylor College of Medicine, and her team found a way to grow norovirus outside the human body. This breakthrough made it possible to test vaccine approaches and treatments more effectively. This step was crucial because common lab animals like mice do not typically get sick from human norovirus.

Today, scientists are testing several experimental vaccines. One example is a 2023 vaccine developed at Washington University School of Medicine in St. Louis that combines protection against norovirus with an existing rotavirus vaccine. Several pharmaceutical companies are also developing candidates, many of which are now in clinical trials, said Amesh Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security, in comments to *Health*.

HilleVax, a Boston-based company, has been testing a norovirus vaccine originally developed by Japan’s Takeda. However, that candidate did not succeed in a phase II trial in June 2024. Meanwhile, a tablet-style norovirus vaccine from San Francisco-based Vaxart has completed phase I testing. Among the most promising efforts is Moderna’s vaccine, which is currently being tested in human volunteers.

Preventing Norovirus, Even Without a Vaccine

Norovirus spreads so easily that stopping it once someone falls ill can be very challenging. This is linked to the virus’s structure. Norovirus is a nonenveloped virus, similar to polio and other stomach-related infections. Because of this, neither hand sanitizers nor soap and water actually destroy the virus, Foster explained. “Handwashing helps because you’re physically rinsing the virus away,” she said.

As a result, basic hygiene practices, especially thorough handwashing, remain some of the most effective ways to lower risk, said Ming Tan, PhD, an infectious disease researcher and associate professor of pediatrics at Cincinnati Children’s Hospital Medical Center, speaking to *Health*.

If norovirus does strike, treatment options are limited. Staying hydrated is essential to avoid complications from fluid loss. Some people may also use medicines to control nausea or diarrhea, either over the counter or by prescription, such as Zofran. If severe symptoms develop, including confusion, high fever, or intense abdominal pain, medical care should be sought right away.