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.

India’s first approved dengue vaccine, QDENGA, could be available in the private market by the first half of 2027, Dr Reddy’s Laboratories said. The company is partnering with Japan’s Takeda to promote and distribute the vaccine in India.

“Subject to the completion of applicable processes with local authorities, the vaccine is anticipated to become available in the first half of 2027,” the companies said.

QDENGA Vaccine: Why The Launch Matters

Also read: Delhi Dengue Cases Rise In September: Is Weather Fueling The Surge?

India’s dengue burden has risen 11-fold over the past two decades. Rapid urbanization, climate change and mosquito breeding have contributed to the growing public health challenge.

A nationwide ICMR dengue surveillance study found that all four dengue virus serotypes — DENV-1 to DENV-4 — are circulating across multiple regions. About one in 14 patients had concurrent infections with multiple serotypes.

QDENGA Approved In India: Who Can Take It?

QDENGA received market authorization from the Drug Controller General of India (DCGI) in July to prevent dengue in people aged 4 to 60 years.

According to Takeda, it can be given regardless of previous dengue infection and does not require pre-vaccination testing.

Since 2022, QDENGA has been approved in 43 countries across Asia, Latin America and Europe. It is also part of Brazil’s National Immunization Program and public immunization programs in Argentina, Colombia and Indonesia.

How Effective Is QDENGA?

READ: Dengue Is Spreading Beyond Monsoons And Into New Regions Across India, Says Expert

QDENGA is designed to protect against all four dengue virus serotypes, regardless of previous dengue exposure.

The DCGI approval is supported by Takeda’s clinical program, which included 19 Phase 1, 2 and 3 trials involving more than 28,000 participants.

The pivotal Phase III TIDES trial included more than 20,000 participants across eight countries. Key findings included:

• 80.2% efficacy against virologically confirmed dengue one year after the second dose.
• 90.4% efficacy against dengue-related hospitalization at 18 months.
• 84.1% protection against dengue-related hospitalization after 4.5 years.
• Data showed protection across all four serotypes for up to seven years.

An Indian Phase III trial involving people aged 4 to 60 years also found the vaccine safe, well tolerated and immunogenic.

What Is QDENGA?

QDENGA (TAK-003) is a live-attenuated tetravalent dengue vaccine targeting all four dengue virus serotypes.

It is given as two 0.5 mL subcutaneous doses, three months apart. The vaccine uses a DENV-2 backbone with structural proteins from DENV-1, DENV-3 and DENV-4.

The WHO recommends QDENGA for use in dengue-endemic settings without pre-vaccination screening. It is also WHO-prequalified for procurement through agencies including UNICEF and PAHO.

QDENGA Manufacturing In India

Dr Reddy’s will handle promotion and distribution in the private market, while Takeda will retain rights to promote and distribute QDENGA in India’s public market.

In February 2024, Takeda partnered with Hyderabad-based vaccine maker Biological E to expand QDENGA production.

Biological E plans to manufacture 50 million doses annually, supporting Takeda’s goal of producing 100 million doses globally each year by the end of the decade.

The company’s production will focus heavily on multi-dose vials for public health sectors and National Immunization Programs in dengue-endemic countries globally.

Nearly one in four doctors globally is aged 55 or older and could reach retirement age within the next decade, according to a new World Health Organization (WHO) report, highlighting growing pressure on health systems.

The WHO has published its National Health Workforce Accounts: Health Workforce Levels and Trends 2026, the first in an annual series providing a global picture of health workforce levels and trends.

The report flagged that ageing among health workers is intensifying workforce shortages in some countries, while an ageing population is simultaneously increasing demand for healthcare services.

The global health worker shortage fell from 20 million in 2013 to 15 million in 2020 and was earlier projected to reach 10 million by 2030. However, newer analysis has revised the 2030 shortage estimate upward to 11.1 million.

“Ageing is the hidden health workforce crisis that requires urgent attention. It is creating a double pressure on health systems, primarily in high-income countries,” said Dr Khassoum Diallo, Acting Unit Head of Health Workforce Policies and Data, WHO Academy.

“We know that better data drives better policy, and these findings reinforce the importance of future-focused action to strengthen health workforce planning, education, employment and retention,” Dr Diallo added.

Also read: Japan Has 107,677 Centenarians; 88% Are Women: Challenges Of An Aging Population

Key Findings From The WHO Report

Based on the latest available data from 122 countries, nearly 25% of doctors are aged 55 or older and could reach retirement age within the next decade. In high-income countries, this rises to nearly one in three.

There are currently more than 70 million health and care workers worldwide. Global health workforce density increased by 52%, from 44.8 per 10,000 people in 2006 to 67.9 in 2025.

The WHO estimates that:

• 67 countries will not have enough health workers to maintain population health needs by 2030.
• The global health workforce shortage is projected to reach 11.1 million by 2030.
• An additional 832,000 health workers are needed just to maintain current age-standardized workforce density, primarily in high-income countries.

Major Gaps Between Rich And Poor Countries

Read More: Unusually High Cancer-Fighting Immune Cells Could Explain Why Some People Live Beyond 100: Study

The report also found major disparities in health worker availability between regions and income groups.

The density of medical doctors is 13 times higher, while the density of nurses and midwifery personnel is six times higher, in the WHO European Region than in the WHO African Region.

Health worker density also remains strongly linked to national income, with high-income countries having substantially greater workforce density than low-income countries.

“Despite gains in workforce production and data reporting, uneven and severe shortages of health and care workers remain, and health worker density remains strongly correlated with national income,” explained Dr Diallo. “Addressing these inequities is essential to achieving Health for All.”

Ageing Population Could Further Increase Demand

The workforce challenge is also unfolding as the global population ages. About one in 10 people worldwide was aged 65 or older in 2024. In high-income countries, the share was nearly one in five. Globally, the proportion is projected to reach about one in eight by 2030.

The WHO noted that population ageing will increase healthcare needs, meaning countries cannot simply aim to maintain their current health workforce density.

“Investing in the health and care workforce is essential to strengthening health systems, safeguarding health security and advancing sustainable development,” said Dr Diallo.

Lung cancer in people who have never smoked is an increasingly recognized global health concern. A new study found that a rare inherited EGFR mutation may increase lung cancer risk by over 60 times in never-smokers.

Lung cancer in never-smokers is the seventh leading cause of cancer death worldwide. Approximately 60% to 80% of lung cancer cases in never-smokers globally occur in females.

The study, published in Science, found that a rare inherited EGFR T790M mutation can increase lung cancer risk by over 60 times in never-smokers and 25 times in smokers.

Smoking itself increases the risk of developing lung cancer fourfold in the general population.

What Did The Study Find?

To look for the rare mutation, researchers evaluated genotyping data from 3.37 million people and found that it occurs in about 1 in 15,850 people.

Among the 17 cancers and non-pulmonary conditions screened, the mutation showed a strong association only with lung cancer. Researchers also traced its origin to southern Appalachian populations in the US.

“Recognition of individuals more likely to carry EGFR T790M, including those with family history of lung cancer, multifocal lung cancer, or lung nodules or Southeastern US ancestry, may help to inform future screening and prevention strategies for those at highest risk,” said the researchers.

“Smoking is bad for lung cancer. This mutation is bad for lung cancer. When you do both, your risk is the sum of those two risks,” said Alexander Gusev, a quantitative geneticist at Dana-Farber. “So, you definitely don't want to smoke.”

The mutation was not linked to any of the 17 other common cancers studied, suggesting that its effects may be largely limited to lung cancer.

Could Genetic Testing Change Lung Cancer Screening?

“Today, lung cancer screening is driven almost entirely by smoking history,” said Jaclyn LoPiccolo, attending physician and lung cancer researcher at Dana-Farber Cancer Institute, who co-led the study.

LoPiccolo added that the findings raise the possibility that, in the future, screening could also be dictated by inherited genetic risk.

“If further studies confirm the benefit, people with EGFR T790M could be identified through genetic testing and offered personalized CT screening to identify lung cancers when they are at their most curable stage,” she said.

How Does The Mutation Increase Risk?

Although most lung cancers are associated with tobacco use or exposure, the proportion diagnosed in people who have never smoked has been rising. Yet the genetic factors underlying these cancers, particularly the role of inherited risk, are not well understood.

In 2005, researchers identified the rare inherited EGFR T790M mutation in a European family with multiple cases of lung cancer. Since then, the mutation has been reported in other families with unusually high rates of the disease.

In the study, LoPiccolo noted that the mutation occurs in about 1 in 15,000 people in the US population, but in certain areas of the Southeastern US, it can be as frequent as 1 in 2,000 people.

Other Lung Cancer Risk Factors

Lung cancer occurs when abnormal cells grow uncontrollably in the lungs. It remains the leading cause of cancer deaths worldwide, with an estimated 2.5 million new cases and 1.8 million deaths in 2022.

Beyond inherited genetic risk, lung cancer can also develop following exposure to second-hand smoke, air pollution, and workplace chemicals and carcinogens.

These include asbestos, silica dust, diesel exhaust, arsenic and other industrial chemicals.

Radon gas is another lesser-known risk factor. It is invisible and odorless, and prolonged exposure to high levels of radon can increase the risk of lung cancer.