Influenza, commonly known as the flu, is a respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. This contagious disease can range from mild to severe, impacting millions annually. Understanding how the flu virus spreads is crucial for public health. This article clarifies established methods of flu transmission and addresses common questions.
How Flu Spreads
Influenza viruses primarily spread through respiratory droplets produced when an infected person coughs, sneezes, or talks. These droplets can land in the mouths or noses of people nearby or be inhaled into the lungs. Larger droplets typically travel less than six feet before settling, meaning close proximity to an infected individual increases transmission risk.
The flu can also spread through smaller airborne particles, sometimes called aerosols, which can remain suspended in the air for longer periods and travel further. Additionally, indirect contact transmission occurs when a person touches a surface or object contaminated with the influenza virus and then touches their own mouth, nose, or eyes. The virus can survive on hard, non-porous surfaces for hours to days, depending on environmental conditions.
Addressing Sexual Transmission of Flu
The influenza virus is not considered a sexually transmitted infection (STI) and is not transmitted through sexual fluids. It primarily infects the respiratory system, leading to symptoms like cough, sore throat, and runny nose.
While close physical contact, including that which occurs during sexual activity, can facilitate the spread of respiratory droplets, transmission is due to the virus’s respiratory nature. The risk comes from breathing airborne particles or direct contact with respiratory secretions, not the exchange of sexual fluids.
Protecting Yourself and Others
Vaccination is a primary strategy for preventing influenza and reducing the risk of serious complications. Annual flu vaccines are updated to target circulating strains and are recommended for most individuals aged six months and older. Even if vaccinated individuals still get sick, the vaccine can help make the illness milder.
Practicing good hand hygiene is another effective measure; frequent handwashing with soap and water for at least 20 seconds, especially after coughing, sneezing, or being in public, can reduce virus transmission. If soap and water are unavailable, an alcohol-based hand sanitizer with at least 60% alcohol can be used. Avoiding touching one’s eyes, nose, and mouth helps prevent the virus from entering the body. Additionally, covering coughs and sneezes with a tissue or into the elbow, and staying home when sick, helps contain respiratory droplets and prevents spreading the virus to others.