Influenza

Influenza (the flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. The best way to prevent the flu is by getting a flu vaccination each year. Every year in the United States, on average 5% to 20% of the population gets the flu; more than 200,000 people are hospitalized from flu complications, and; about 36,000 people die from flu-related causes. Some people, such as older people, young children, and people with certain health conditions, are at high risk for serious flu complications.

Types of Influenza

Influenza is caused by three types of RNA viruses called influenza types A, B and C, which all belong to the family Orthomyxoviridae.

Influenza Prognosis

Should I get the Flu Shot?

Influenza Immunization

Influenza Symptoms

Influenza Infection in Animals

Influenza Pandemics

Influenza Research

Influenza Treatments

Influenza Epidemiology

Latest Influenza News and Research

Respiratory infections can reactivate dormant breast cancer cells

Researchers at the University of Colorado Anschutz Medical Campus, Montefiore Einstein Comprehensive Cancer Center (MECCC), and Utrecht University have found the first direct evidence that common respiratory infections, including COVID-19 and influenza, can awaken dormant breast cancer cells that have spread to the lungs, setting the stage for new metastatic tumors.

30 Jul 2025

Wastewater surveillance for detecting COVID-19 offers early warning and cost savings

Wastewater surveillance at treatment plants offers a low-cost, early warning method for detecting COVID-19. Researchers in Japan conducted an economic evaluation of a system for long-term care facilities that combines wastewater data with clinical testing thresholds to guide timely interventions.

30 Jul 2025

Dental floss may offer a novel vaccine delivery method

Researchers have demonstrated a novel vaccine delivery method in an animal model, using dental floss to introduce vaccine via the tissue between the teeth and gums.

28 Jul 2025

UK self-tests overstate accuracy and pose usability risks

Analysis of UK self-tests reveals critical flaws in accuracy claims, highlighting risks and the need for enhanced regulatory standards for consumer safety.

28 Jul 2025

Study finds past H1N1 exposure shields animals from deadly H5N1

Preexisting immunity to the 2009 H1N1 influenza virus provided near-complete protection against severe H5N1 disease and transmission in ferrets, even after high-dose exposure. In contrast, H3N2 immunity alone offered only partial, inconsistent protection.

28 Jul 2025

RSV causes severe outcomes and heart complications in older adults

Respiratory syncytial virus (RSV) is a well-known cause of infections in children, but it's understudied in older individuals.

23 Jul 2025

AI and wastewater surveillance unite to detect emerging viruses

Wastewater surveillance became a popular choice among public health officials looking to track rapid virus mutations and spread patterns during the COVID-19 pandemic.

21 Jul 2025

APOE ε4 variant reveals hidden risk factors beyond Alzheimer’s

Researchers discovered that people carrying the APOE ε4 gene variant share a unique immune-related protein signature across their blood, brain, and cerebrospinal fluid—regardless of neurodegenerative disease diagnosis. This signature reveals a fundamental, disease-independent vulnerability linked to APOE ε4, reframing our understanding of genetic risk in conditions like Alzheimer's, Parkinson’s, ALS, and FTD.

21 Jul 2025

Lipoxygenase emerges as a promising antiviral agent against severe fever with thrombocytopenia syndrome

Severe fever with thrombocytopenia syndrome (SFTS) was reported in Asia, with a fatality rate that can reach as high as 50%.

18 Jul 2025

Local climate and wildlife factors help predict avian flu outbreaks in Europe

Several local factors - including the minimum temperature reached in autumn, the water level in lakes and ponds in winter, and the presence of mute swans (Cygnus olor) - could be key for predicting the potential of an outbreak of highly pathogenic avian flu (HPAI) occurring in Europe.

17 Jul 2025

Routine vaccines may be the key to fighting antibiotic resistance

A study reveals that rising vaccine coverage in children is linked to reduced antibiotic prescriptions, suggesting a shift in the fight against drug resistance.

16 Jul 2025

Genetic secrets of Spanish flu revealed through century-old sample

Researchers from the universities of Basel and Zurich have used a historical specimen from UZH's Medical Collection to decode the genome of the virus responsible for the 1918-1920 influenza pandemic in Switzerland.

14 Jul 2025

Early antibiotic exposure weakens infant immune development

A new study led by researchers at the University of Rochester Medical Center (URMC) found that early-life exposure to antibiotics can impair an infant's developing immune system, and that a naturally occurring metabolite may hold the key to reversing that damage.

14 Jul 2025

Therapeutic potential of houttuynia cordata polysaccharide in H1N1 and MRSA-induced acute pneumonia

This new article publication from Acta Pharmaceutica Sinica B, discusses how an anti-complement homogeneous polysaccharide from Houttuynia cordata ameliorates acute pneumonia with H1N1 and MRSA coinfection through rectifying Treg/Th17 imbalance in the gut–lung axis and NLRP3 inflammasome activation.

12 Jul 2025

New microchip tracks antibody-virus interactions from a single drop of blood

A new microchip invented by Scripps Research scientists can reveal how a person's antibodies interact with viruses-using just a drop of blood.

12 Jul 2025

Scientists identify key role of T-bet in flu memory B cells

At the surface, the immune response to a flu virus is simple. Some cells recognize the pathogen and send a signal to the immune system, and immune cells produce a potentially lifesaving antibody against the virus. Antigen in, antibody out.

11 Jul 2025

Does soup really work when you’re down with cold or flu?

A systematic review found that chicken-based and vegetable-enriched soups may modestly reduce the severity and duration of acute respiratory tract infections. However, stronger evidence is needed before soup can be recommended as a clinical treatment.

10 Jul 2025

Letting bird flu run its course could spark wider pandemic

In a Policy Forum, Erin Sorrell and colleagues – a coalition of virologists, veterinarians, and health security experts – argue that the recent proposal to permit the uncontrolled spread of highly pathogenic avian influence (HPAI) among U.S. poultry to identify birds that survive infection is dangerous and unethical.

4 Jul 2025

Mature dendritic cell vesicles enhance influenza vaccine effectiveness

Influenza hemagglutinin subunit vaccines are more effective and offer better cross protection against various influenza virus challenges when combined with a mucosal adjuvant that enhances the body's immune response, according to a study by researchers in the Institute for Biomedical Sciences at Georgia State University.

2 Jul 2025

Vaccination plays key role in preventing cardiovascular events after infection

Today, a new ESC Clinical Consensus Statement published in the European Heart Journal discusses the key role of vaccination in preventing cardiovascular events following various viral and bacterial infections.

1 Jul 2025