There's been an alarming increase of respiratory and gastrointestinal viruses in the United States lately, causing anxiety about a so-called "quad-demic". According to surveillance reports, influenza, COVID-19, RSV and norovirus are at very high levels everywhere. While the surge aligns with patterns typical for this season, several epidemiologists view simultaneous infections of such proportions to pose risks not only to individual healthcare but public health.

The incidence of the quad-demic should vary with seasonal patterns, vaccination rates, and public health interventions. Each virus alone is relatively easy to manage; however, the effect of all together could lead to overburdening of health care facilities and increase risks for those at higher risk. Continuing surveillance, early testing, and proactive prevention measures will play an important role in the control of these infections going forward.

While the term "quad-demic" sounds daunting, it must be taken into perspective. For years, we have had all these viruses together, and we have the capabilities to mitigate some of the risk. Vaccination, proper hygiene and using common sense helps individuals get through the season unscathed. Is the quad-demic a permanent fixture or just another seasonal wave? Let's break this down.

What is the Quad-demic?

Typically, flu, COVID-19, and RSV have been the primary culprits behind seasonal respiratory infections. However, norovirus, a highly contagious stomach bug, has emerged as a fourth significant player, inducing fears of a more severe and widespread viral outbreak. According to the Centers for Disease Control and Prevention (CDC), the U.S. recorded nearly 500 norovirus outbreaks between August and December 2023, a substantial rise from the previous year’s numbers.

While the term "quad-demic" may sound ominous, the seriousness and consequences of such infections should be weighed in light of the U.S. healthcare system's experience with managing viral surges since the start of the COVID-19 pandemic.

1. Influenza (Flu)

Flu continues to be one of the most common and alarming seasonal illnesses. In the period spanning from 2023 to 2024, there were approximately 40 million cases of flu, and thousands of hospitalizations along with reported 47 deaths have been reported this season. Flu symptoms include fever, chills, cough, sore throat, muscle pain, and fatigue, with most recovering within a week or two but risky factors for severe illness effects occur in young children, elderly, and people with chronic conditions.

2. Covid-19

Despite its reduction from the first pandemic peak, COVID-19 is still rampant. The CDC estimates that alone between October and December 2023, there were between 2.7 and 5 million cases in the U.S. Hospitalization has increased by cities such as Los Angeles, Chicago, and New York. Symptoms are closely similar to the flu, fever, cough, and fatigue but uniquely presents in some cases as loss of taste and smell.

3. RSV

RSV is the most common cause of lower respiratory infections in infants, older adults, and immunocompromised individuals. While RSV peaked late in 2023 and early 2024, it continues to be a threat because it can lead to bronchiolitis and pneumonia. It is very similar to the common cold, presenting with symptoms such as congestion, runny nose, coughing, and fever, which can make it difficult to differentiate from flu or COVID-19 without testing.

4. Norovirus

Norovirus, also called the "stomach flu," is a highly contagious infection of the gastrointestinal tract, not a respiratory virus. It transmits quickly from contaminated food and water and contact with contaminated surfaces, causing such symptoms as diarrhea, vomiting, nausea, and stomach pain. Cases have shot up, the CDC said Monday, with reports of outbreaks surging compared with last year.

Is There a Challenge In Diagnosis Due to Overlapping Symptoms?

The greatest challenge during the quad-demic is how the four viruses are alike and thus make identification very hard with no testing applied. Most cases present symptoms common to all viruses: fever, tiredness, body pains, and respiratory, which includes coughing and congestions for influenza, COVID-19, and RSV; the other would be norovirus symptoms as nausea and vomiting can appear even in extreme influenza and COVID-19. This overlap increases the risk of misdiagnosis and delayed treatment, hence the need for early testing and proper medical guidance.

Also Read: Is US Preparing For A Quad- demic 2025?

Effective Prevention Strategies That Work

The best defense against these viruses is a combination of vaccines, hygiene, and lifestyle precautions. While lifestyle modifications are highlighted as part of the constant need to eat healthy, ensure daily movement and drinking adequate amount of fluids. There is a sure short two preventive strategies that are effective:

Vaccination

• Flu vaccine: Annual flu shots reduce the severity of infection, allergic flare ups and hospitalizations.
• COVID-19 vaccine: Though COVID-19 cases have declined, vaccination remains critical in preventing severe outcomes.
• RSV vaccine: Available for those aged 60 years and older, especially those with underlying conditions.
• Norovirus vaccine: No vaccine is yet available, but mRNA vaccine research is in progress.

Hygiene and Sanitation

• Washing hands frequently with soap and water for at least 20 seconds, especially after public exposure.
• Disinfect frequently touched surfaces regularly, use sanitiser when outside.
• Avoid close contact with infected people and wear masks.

Do You Need To Wear A Mask All The Time?

While debates on masked wear continue on, experts on mask-wear affirm that this does not only have a historical precedent but works towards reducing airborne viruses spreading within the environments. Hospitals, though, ensure masking in key sections of themselves. Publicized mask-wear remains a discretion, though massing indoors still goes a longer way in cases like peak flu seasons.

If you notice the symptoms of these viruses, then it's best to be confined at home and avoid having face-to-face interaction with others and seek immediate attention from your physician if your condition worsens. Quarantining for some days can decrease the spread of infection.

As we move into the first half of 2025 and beyond, staying informed and proactive is the best strategy for maintaining health and avoiding unnecessary panic. The key takeaway? Stay vigilant, but don’t be alarmed—these viruses are here, but so are the means to fight them.

The US Food and Drug Administration (FDA) is investigating a possible cancer risk linked to Novartis' gene therapy Zolgensma after the Swiss drugmaker reported several cases of tumours in patients who had received the treatment. It included two patients aged less than two years old with spinal muscular atrophy (SMA) in which investigators found evidence linking the tumour to the therapy.

Novartis's SMA Drug Under Investigation For Causing Tumour Growth

Zolgensma is a one-time gene therapy used to treat children under two years of age with spinal muscular atrophy (SMA), a rare genetic disorder that causes progressive muscle weakness. More than 6,000 patients have received the treatment since its approval in 2019.

In a safety update issued on November 6, the FDA said it had received reports of neoplasia, or tumour formation including malignancy, known as insertional oncogenesis. This occurs when genetic material delivered by a gene therapy becomes integrated into a patient's DNA and contributes to abnormal cell growth.

In two cases, molecular analysis of tumour tissue showed that DNA from the therapy's viral vector had integrated into the patients' genomes within the GLI1 gene, which can promote cancer when activated. The FDA said it was also investigating a third tumour linked with GLI1.

The agency said tumours had been found in the central and peripheral nervous systems, spinal and paraspinal regions, and kidney.

Also read: Drug-Resistant Epileptic Seizures Reduce By Over 90% With Experimental Gene Therapy

What Has The FDA Said About The Risk?

The FDA is assessing whether regulatory action is needed and is reviewing whether the long-term safety studies address the risk.

However, it stressed that the benefits of both Zolgensma and Novartis' other SMA gene therapy, Itvisma, continue to outweigh their potential risks for their approved uses.

The two therapies use the same viral vector and genetic material but are administered differently. Zolgensma is given through an intravenous infusion to children under two, while Itvisma is injected into the spinal canal and is approved for adults and children aged two and older. The FDA said no cases of tumour formation had been reported following Itvisma treatment so far.

The risk of tumour formation due to viral DNA integration is already mentioned in Zolgensma's information as a theoretical risk. The FDA said patients receiving either treatment should be monitored for tumour formation.

Also read: India Proposes Stricter Drug Rules: Tougher Quality Checks, Licence Suspension

What Novartis Said?

Novartis said the two patients whose tumours showed evidence of vector DNA integration had undergone treatment and continued to be monitored.

In a statement, the company said, “Patient safety is our priority. In each case, we timely and appropriately notified health authorities and will continue to work with them on next steps.”

The company also said it had received nine tumour reports since Zolgensma's approval and that the risk was included in the drug's prescribing information.

The disclosures have raised questions among families and patients about when the information was shared. SMA Europe urged the company to explain what is known, what remains uncertain and what the findings could mean for children who have already received treatment. Novartis did not provide details on where the two new cases were in its statement.

The United States is in the midst of one of the worst measles outbreak. It has reported more than 5,000 measles cases in 2026, marking the highest annual total cases since 1991.

This has raised concerns that the country could lose its measles elimination status after more than 25 years.

Measles Cases In The US Cross 5,000

Also read: EXCLUSIVE: Ex-CDC Vaccine Advisor Says Measles Outbreak Bigger Than Reported, Slams RFK Jr’s ‘No-See Evil’ Approach

According to an update issued on November 6, the US Centers for Disease Control and Prevention (CDC) reported 5,182 confirmed cases as of November 5. This is the first time since 1991 that the annual number of infections has crossed the 5,000 mark.

The latest figure marks an increase of 330 cases from the previous week. The CDC also reported 562 hospitalisations due to measles this year, which accounts for 11% of confirmed cases.

The outbreak has spread across 47 jurisdictions and 43 outbreaks reported so far in 2026. Approximately around 96% of infections have been linked to outbreaks, while 96% of people infected were either unvaccinated or their vaccination status was unknown.

The expanding measles outbreak has sparked concerns about the country's ability to maintain the elimination status it achieved in 2000.

Could The US Lose Its Measles Elimination Status?

Also read: 'It’s The Best-Studied Vaccine In Human History': Former CDC Adviser Busts Common Myths About COVID Vaccines

The US declared measles eliminated in 2000, meaning that the country had stopped continuous transmission of the virus for at least 12 months, but infections could still occur when people brought the virus into the country from abroad. However, recent outbreaks have raised concerns that measles could become endemic again.

According to the CDC, elimination status is determined by the absence of continuous measles transmission in a geographical area for 12 months or longer, supported by an effective disease surveillance system.

The United States is facing a review of its elimination status by the Pan American Health Organization (PAHO), which is expected to assess the country's progress in controlling transmission during its November 2026 meeting.

The review will examine whether the ongoing outbreaks represent sustained transmission of the virus and whether the country continues to meet the criteria for elimination. Losing elimination status would that the country had failed to interrupt sustained transmission of the virus.

The Americas region had already lost its measles elimination status in November 2025 after Canada experienced continuous transmission for at least 12 months.

What Happens If The US Loses Its Elimination Status?

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Losing measles elimination status would mark a major setback for public health efforts that successfully interrupted continuous measles transmission in the country in 2000.

It would also signal that the virus is circulating continuously within the population rather than appearing mainly through imported infections that cause outbreaks that get eventually contained.

However, elimination status can be regained if sustained transmission is interrupted and the required criteria are met. Public health experts continue to emphasise the importance of maintaining high vaccination coverage, identifying cases quickly and responding to outbreaks promptly.

Who Is Being Affected By The US Measles Outbreak?

The latest CDC data show that measles is affecting people across different age groups. Adults aged 20 and older accounted for 2,132 cases, followed by 2,104 infections among people aged five to 19. Children younger than five accounted for 908 cases.

The CDC reported four measles deaths in 2026, compared with three during the whole of 2025. However, the CDC's national death count differs from figures reported by individual state health departments because the agency uses National Center for Health Statistics mortality data for its official tally.

Pennsylvania has been among the hardest-hit states, reporting 1,487 cases, 287 hospitalisations and six associated deaths, according to Reuters. The outbreak has also spread to South Carolina and Utah, which reported 670 and 536 cases, respectively.

According to state health department reports, the country has recorded eight measles-related deaths this year: six in Pennsylvania, one in New York and one in Wisconsin. At least four involved children or infants.

Life-threatening bleeding episodes among US infants have risen sharply as more parents refuse the routine vitamin K shot given at birth, two new studies have found.

Published in JAMA and JAMA Pediatrics, the studies found that the proportion of newborns who missed the vitamin K shot more than doubled between 2017 and 2025, reaching 6.8%. These infants were also more likely to experience bleeding, including bleeding in the brain.

Although the studies do not establish causation, the parallel rise in refusals and bleeding episodes is significant, said Dr Steven Woolf, an epidemiologist at Virginia Commonwealth University and lead author of the JAMA Pediatrics study, as reported by NBC News.

"Now we're stepping away from that, and we're seeing the consequences," Woolf said.

Vitamin K shots have been standard newborn care since 1961 and help prevent vitamin K deficiency bleeding (VKDB), a rare but potentially life-threatening condition.

Infant Bleeding Episodes Nearly Quadrupled Since 2017

Woolf and colleagues analysed medical records of more than 11 million infants aged six months and younger between 2017 and 2025.

During this period, the proportion of newborns receiving a vitamin K shot fell from 97.7% to 95%, while vitamin K deficiency bleeding nearly quadrupled.

The researchers identified 5,217 bleeding events during the study period. The rate in 2025 was approximately double that in 2024, Woolf said.

The researchers noted that the increase coincided with declining public trust following the COVID-19 pandemic, growing vaccine hesitancy and parental scepticism about routine newborn interventions.

Vitamin K Refusals More Than Double To 6.8%

A separate JAMA study by Dr Kristan Scott and colleagues analysed medical records of more than 5.2 million US infants born between 2017 and 2025.

The proportion of newborns who missed the vitamin K shot rose from 3.1% in 2017 to 6.8% in 2025. It had reached 5.1% by the end of 2024.

The study also found that infants who did not receive the shot had:

• A 47% higher risk of bleeding during their first six months.
• More than twice the risk of bleeding in the brain.
• More than twice the risk of death associated with a bleeding diagnosis during their birth hospitalisation.

The authors estimated that one additional bleeding event would occur for every 114 newborns who missed the vitamin K shot.

Separately, an analysis of more than one million births by health data company Truveta for Reuters found that vitamin K refusals increased by more than 57% between January and June 2026.

Why Is Vitamin K Important For Newborns?

Vitamin K is a fat-soluble nutrient essential for blood clotting and bone health. Newborns naturally have low levels, leaving them vulnerable to VKDB.

The American Academy of Pediatrics (AAP) has recommended a vitamin K injection for all newborns since 1961.

Without adequate vitamin K, babies can develop spontaneous bleeding, including severe internal bleeding and bleeding in the brain. These episodes can cause permanent brain damage or death.

Importantly, the vitamin K shot is not a vaccine. It is a one-time injection given shortly after birth to protect babies against VKDB.

Breast milk contains relatively little vitamin K. Exclusively breastfed babies who miss the birth injection therefore remain vulnerable to deficiency bleeding.

The researchers also found increased use of oral vitamin K. However, oral doses are less effective than intramuscular injections, particularly in preventing late-onset VKDB, which can occur weeks or months after birth.

Why Are More Parents Refusing Vitamin K Shots?

Vitamin K refusals have risen since the COVID-19 pandemic amid growing parental concerns about vaccines and routine newborn interventions.

Health experts have also raised concerns about declining trust in health authorities and mixed messages surrounding preventive care.

Refusals have accelerated under US Health Secretary Robert F Kennedy Jr, who has questioned vaccine safety and overseen changes to federal childhood vaccination recommendations.

A US Department of Health and Human Services spokesperson said the Centers for Disease Control and Prevention (CDC) continues to recommend vitamin K shots for newborns. However, the department did not say whether the agency would begin tracking refusals or associated bleeding episodes.