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 Pandemics

Influenza Prognosis

Influenza Treatments

Influenza Infection in Animals

Influenza Research

Should I get the Flu Shot?

Influenza Symptoms

Influenza Immunization

Influenza Epidemiology

Latest Influenza News and Research

Cardiometabolic diseases remain leading cause of excess American mortality

Between 1999 and 2022, the US had substantially higher death rates than other wealthy nations, largely due to cardiovascular disease, metabolic diseases (including diabetes), Alzheimer's disease and related dementias, and drug and alcohol complications.

8 May 2026

Infectious H5N1 virus detected in dairy farm air

Findings from California dairy farms show H5N1 in air and wastewater, indicating overlooked transmission routes and implications for outbreak management.

8 May 2026

Study explores nasal spray flu vaccine effects in children

A new study will explore the effects of a nasal spray flu vaccine on children's immune systems, aiming to boost future protection and lower vaccine hesitancy rates.

7 May 2026

Cell swelling in macrophages may trigger stronger inflammatory immune responses

As part of the body's first line of defense against foreign invaders, macrophages play an integral role in the innate immune system.

7 May 2026

New blood test predicts illness progression and treatment response

Scientists are developing a test which could one day be used to predict how a patient's illness will progress, and even how well they will respond to treatment.

6 May 2026

H5N1 spreads through multiple routes on infected dairy farms

The H5N1 strain of highly pathogenic avian influenza H5N1 has been detected in over 700 herds of dairy cows in California, the largest dairy-producing state in the U.S.

5 May 2026

Cruise ship-linked hantavirus cases highlight zoonotic infection risks

The Global Virus Network (GVN), representing eminent human and animal virologists from more than 90 Centers of Excellence and Affiliates in over 40 countries dedicated to advancing research, collaboration, and pandemic preparedness, is closely monitoring reports of a hantavirus cluster linked to a cruise ship traveling in the Atlantic, which has resulted in multiple severe cases and fatalities.

5 May 2026

How a common gut bacterium may protect health

Akkermansia muciniphila's impact on immunity and pregnancy outcomes underscores its promise as a probiotic, with implications for infectious disease treatment.

4 May 2026

Extreme weather and airborne dust linked to rising Valley fever cases in El Paso

A new study by researchers at The University of Texas at El Paso has identified a significant rise in Valley fever cases in El Paso over the past decade and found strong connections between the disease and extreme weather, wind and airborne dust.

29 Apr 2026

Why H2N2 flu is back on the pandemic preparedness radar

A historical review in Vaccine warns that global H2N2 immunity has sharply declined since the 1957 Asian influenza pandemic, leaving most people without H2-specific protection if the virus re-emerges. The authors highlight animal reservoirs, waning birth-cohort immunity, and modern H2 vaccine platforms as key priorities for pandemic preparedness.

28 Apr 2026

Scientists map 239 human-infective RNA viruses to track future outbreak risks

Researchers updated the global catalogue of human-infective RNA viruses to 239 ICTV-recognised species, incorporating taxonomy, discovery dates, locations, genome links, host range, transmissibility, and transmission routes. The dataset shows that most known human-infective RNA viruses remain strictly zoonotic, while only a minority are endemic in humans or capable of epidemic spread.

26 Apr 2026

Influenza D shows strong potential to spill over to humans

The influenza D virus that researchers say has been flying under the radar since its detection in animals in 2011 can vigorously make copies of itself in human cells and lung tissue samples, a new study shows.

24 Apr 2026

Nasal memory cells help slow influenza virus at entry

Memory cells in the nose slow the influenza virus as soon as it enters the body. They reduce viral levels and may help protect against more severe illness.

23 Apr 2026

UPV researchers develop rapid sensor for detecting active tuberculosis

A research team at UPV is leading the development of a sensor that paves the way for the rapid, selective and cost-effective detection of active tuberculosis.

20 Apr 2026

What still drives childhood vaccine gaps in the United States

A nationwide analysis of provider-verified NIS-Child data from 2010 to 2023 found that US childhood vaccination coverage remained generally high but was consistently shaped by social and structural factors such as maternal education, income, insurance, language, and region. The study also showed that coverage of the combined seven-vaccine series rose over time, yet persistent disparities remained, especially for vaccines such as influenza, hepatitis A, and rotavirus.

19 Apr 2026

Childhood flu infection leaves lasting immune imprint

A study reveals how childhood flu infections impact long-term mortality risk, highlighting implications for vaccination and future outbreak management.

17 Apr 2026

Hidden viral reservoirs in tonsils may explain school-year respiratory outbreaks

A study conducted at the University of São Paulo (USP) in Brazil reveals that tissues such as the tonsils and adenoids can serve as hiding places for the rhinovirus, which causes the common cold and is responsible for most respiratory infections worldwide.

17 Apr 2026

Scientists warn of a silent surge in resistant Aspergillus and Candida

An increasing number of fungi are becoming resistant to medication, posing serious risks for patients with weakened immune systems. That is why fifty researchers from around the world, led by Radboudumc, are calling for action against drug‑resistant fungi. Their call has been published in Nature Medicine.

17 Apr 2026

New flu vaccine approach targets multiple virus strains

Doctors recommend getting your flu shot annually, since the specific influenza strain it targets varies from year to year. But what if the shot could be more effective while protecting against more strains?

15 Apr 2026

NTU Singapore and partners develop new inhaled treatment for severe lung infections

Nanyang Technological University, Singapore (NTU Singapore) is working with China's Southern University of Science and Technology (SUSTech) and Swedish biotechnology company Lipigon Pharmaceuticals AB to develop a new inhaled treatment aimed at helping patients recover faster from severe lung infections.

13 Apr 2026