Cancer is a large group of diseases that can start in almost any organ or tissue of the body when abnormal cells grow uncontrollably, and go beyond their usual boundaries to invade adjoining parts of the body. According to the World Health Organization (WHO), it is the second most common cause of death globally, accounting for millions of deaths every year. Lung, prostate, colorectal, stomach and liver cancer are the most common types of cancer in men, while breast, colorectal, lung, cervical and thyroid cancer are the most common among women. However, these are not necessarily the deadliest forms of cancer.

What makes cancer the deadliest depends upon how many people have it and what percentage of those people actually survive. Cancer researchers determine this on the basis of five-year relative survival. This is the percentage of people who are expected to survive the effects of a given cancer, excluding their risk of other possible causes of death, for five years past a diagnosis. It is also important to note that what makes cancer really deadly is that practically no cure for it. A cure for cancer would imply that there are no cancerous cells remaining in the body.

Here are the 5 deadliest cancers in the U.S., according to SEER five-year relative survival data for cases diagnosed between 2014 and 2020.

1. Pancreatic cancer occurs when cells in your pancreas, a gland in your abdomen that aids digestion, mutate and multiply out of control, forming a tumour. Major risk factors include smoking, obesity, diabetes, chronic pancreatitis, certain genetic mutations and environmental chemical exposure.

2. Esophageal cancer develops in the oesophagus, which is the tube that connects your throat to your stomach.

3. Liver cancer and intrahepatic bile duct cancer originate in the liver or bile ducts, often linked to hepatitis infections, heavy alcohol use, obesity, and aflatoxin exposure.

4. Lung and bronchus cancer primarily caused by smoking, secondhand smoke, and environmental pollutants, affects the lungs and airways, making it the leading cause of cancer death in the US.

5. Acute myeloid leukaemia (AML) is an aggressive blood and bone marrow cancer that progresses rapidly, often linked to genetic mutations, radiation exposure, and certain chemicals.

ALSO READ: Why Are Lifestyle Factors Making Millennials Vulnerable To Cancer?

Flu cases have surged in the United States and experts along with the data from the Centers for Disease Control and Prevention (CDC) pointed out that this will most likely get worse. The CDC data revealed that last week there were more than 19,000 patients with influenza who were admitted to a hospital. This is an up of about 10,000 from the previous week. The CDC also estimated that at least 7,5 million people have been sickened, and over 3,100 people died from the flu.

Not only that, but there has been a rise in unprecedented winter sickness, including winter vomiting bug or the norovirus, COVID and whooping cough. All of these are slamming the US altogether. So far, this season has reported 81,000 hospitalization, and questions and concerns have been raised on the effectiveness of vaccines.

Most cases brought to hospitals have been positive for influenza A. Superclade K of the influenza A is responsible for this surge.

Read: Flu Cases Are On The Rise This Holiday Season: CDC

Where Is The Flu Surging?

In the US, New York saw the highest number of positive flu cases in a single week for the week ending with December 20, confirmed the New York State Department of Health. Connecticut is up next that saw the climb "to highest levels doctors have ever seen", confirmed the news outlet WFSB-TV. California too saw an increase of flu cases statewide. Dawn Terashita, who monitors acute communicable disease at LA County's Department of Public Health said, "it is scary to hear that this year might be worse" than last year.

What Is Influenza A?

As per the National Institutes of Health, US, influenza viruses that contains single-stranded RNA that are classified into three types: A, B, and C. Type A and B cause annual epidemics and even pandemics, while type C is a less common disease.

As per the Centers for Disease Control and Prevention (CDC), Influenza A viruses are descendants of the 2009 H1N1 pandemic virus that emerged in the spring of 2009 and caused a flu pandemic. These viruses, scientifically called the "A(H1N1)pdm09 virus," and more generally called "2009 H1N1," have continued to circulate seasonally since 2009 and have undergone genetic and antigenic changes.

Influenza A(H3N2) viruses also change genetically and antigenically. Influenza A(H3N2) viruses have formed many separate, genetically different clades in recent years that continue to co-circulate.

Common Signs And Symptoms of Influenza A

• Fever or chills
• Dry cough
• Sore throat
• Headache
• Fatigue

The symptoms usually appear 1 to 4 days after exposure and could linger for a week.

Also Read: A ‘Super Flu’ K-Strain Is Raising Early Christmas Alarms, Here’s What We Know

Can You Die From Flu?

As per the infectious physician at the Johns Hopkins University Center for Health Security, as reported in Scientific American, "Dying from the flu is not like dying from a bullet or a black widow spider bite. The presence of the virus itself isn't going to be what kills you. An infectious disease always has a complex interaction with its host.”

Will The Old Vaccine Work Against This New Strain?

"The vaccine remains the most effective means to prevent disease. We still want to encourage people to get the vaccine," said Professor Antonia Ho, Professor and Honorary Consultant in Infectious Diseases at the University of Glasgow. Experts have stressed enough on the immunity that one can receive from the vaccine that that these flu jab remain the best defense against the flu, even though the current strain circulated may have drifted away from the strain included in this year's jab.

Flu infections are climbing across the United States at a time when holiday travel is at its peak, and New York is among the states facing the brunt of the surge. For the week ending December 20, New York recorded 71,123 positive flu cases, the highest weekly total the state has ever reported, according to the New York State Department of Health. This marked a 38 percent jump compared with the previous week.

New York is one of 14 states that logged high or very high levels of outpatient visits for influenza-like illness during the week ending December 13, data from the Centers for Disease Control and Prevention shows. High flu-like activity was also reported in Washington, DC, New York City, and Puerto Rico.

By December 16, flu cases were rising or expected to rise in 47 states, with Hawaii the only state showing a decline, according to CDC projections. Overall, the agency notes that the current level of seasonal flu activity mirrors patterns seen in several earlier years. What sets this season apart, however, is the emergence of a new flu strain.

Experts say it is too early to determine whether the new strain is causing a higher number of infections or more serious disease. “What we do know is that cases are clearly going up, and influenza activity is increasing across much of the country,” said Andrew Pekosz, co-director of the Johns Hopkins Center of Excellence in Influenza Research and Response, during a health briefing on December 16. He added that this upward trend is expected to continue into the new year.

Influenza A Symptoms 2025: What Is The New Flu Strain Spreading In The US?

The strain drawing attention this season is subclade K, a variant of the influenza A(H3N2) virus that is now circulating widely in the United States. It has played a role in the sharp rise in flu cases nationwide, with New York reporting its highest-ever weekly count of confirmed infections. Similar increases have been seen in many other parts of the country.

Subclade K has previously driven outbreaks in Japan, the United Kingdom, and Canada, prompting questions about whether the current flu vaccine is well matched to the strain. According to USA Today, while the match may not be exact, experts believe the vaccine still reduces the risk of serious complications.

Influenza A Symptoms 2025: Fewer Americans Getting Flu Shots

Another factor that may be fueling the rise in flu cases is a drop in vaccination rates. During the 2025–2026 flu season so far, more than 47.6 million flu shots have been administered at retail pharmacies and doctors’ offices. That figure is roughly 3 million lower than at the same point last season, CDC data shows.

The recent government shutdown, which lasted from October 1 to November 12, may also have disrupted flu surveillance and vaccination efforts. This, in turn, could have influenced vaccination uptake, said Jennifer Nuzzo, professor of epidemiology and director of the Pandemic Center at Brown University School of Public Health. Her comments were included in a flu report published on December 19 in the Journal of the American Medical Association.

Flu activity is increasing all thanks to the holiday season. The Centers for Disease Control and Prevention (CDC) data shows that due to a surge in holiday travel and gathering, the flu cases have gone up. The CDC estimates that there have been at least 4.6 million illnesses, 49,000 hospitalizations and 1,900 deaths from flu this season so far.

Public health experts have also revealed that many of this season's cases are linked with the new flu strain, called the subclade K. This is a variant of the H3N2 virus, which is a subtype of influenza A.

According to the CDC, 89% of the 163 H3N2 virus samples collected and genetically analyzed since September 28 belonged to subclade K.

So far this season, three pediatric flu deaths have been reported, based on an ABC News tally. Last season, 288 children died from the flu in the U.S., matching the toll seen during the 2009 H1N1 pandemic. A CDC study published earlier this year found that about 90% of those children were unvaccinated.

Read: New Aggressive Flu Strain Is Now A Health Threat In US

Will The Old Flu Vaccine Protect You Against The New Subclade K?

The real reason why concerns are prompted about the effectiveness of the seasonal vaccine is because the virus underwent more mutation than scientists expected over summers. This mutant is called the 'subclade K' or 'super flu'. While it is true that most cases this season are of the 'super flu' strain, experts say that the flu jab is still offering a strong protection.

"The vaccine remains the most effective means to prevent disease. We still want to encourage people to get the vaccine," said Professor Antonia Ho, Professor and Honorary Consultant in Infectious Diseases at the University of Glasgow. Experts have stressed enough on the immunity that one can receive from the vaccine that that these flu jab remain the best defense against the flu, even though the current strain circulated may have drifted away from the strain included in this year's jab.

Data from the UK Health Security Agency (UKHSA) also show that vaccines is performing as expect, despite the emergence of subclade K.

Every year, experts from the World Health Organization, the Centers for Disease Control and Prevention, and other global health agencies closely track flu trends around the world. They study which strains are spreading and use that data to predict which ones are most likely to dominate the upcoming flu season. The annual flu vaccine is then designed to protect against three or four of those strains.

It’s also worth understanding that more than one influenza A strain usually circulates at the same time. So even if the vaccine is not an exact match for a newer H3N2 strain, it still protects against other common flu viruses, which matters, notes Stony Brook Medicine.

When a new variant emerges, the flu shot can still offer what doctors call cross-protection. In simple terms, the antibodies your body makes after vaccination can recognize similar flu viruses and respond to them. You might still get sick, but the vaccine greatly lowers the chances of severe illness, hospitalization, or worse.

The vaccine offers protection against both types of influenza, including A and B.