Some research shows that approximately half of flu cases may stem from airborne transmission. Knowing how the flu is spread and understanding flu transmission can help you prevent infection and minimize your risk.
This article will discuss how flu is spread, including how long the flu is contagious and the flu incubation period. It will explain the difference between droplets and airborne spread, and how that might affect transmission.
Flu Transmission Explained
The flu is a virus that is most often spread when someone comes into contact with droplets from an infected person. These droplets are produced when a person with the flu coughs or sneezes, spreading infected mucus around them for up to 6 feet.
Droplets vs. Aerosols
Droplets are heavy. They generally sink to the ground within about 6 feet of the infected person. That means if you stay more than 6 feet away, you are less likely to become infected. Scientists believe that most flu transmission happens when a person inhales these droplets or enters their eye, nose, or mouth.
Aerosols are produced by coughing or sneezing, just like droplets. However, they are smaller and lighter, so they float in the air longer.
If the flu is airborne, that means the infectious virus can spread even if you stay more than six feet away. Researchers are still unclear about how much of the flu is spread via airborne transmission, but one study indicates that at least half of transmission happens via airborne particles.
Through Human Contact
When you’re close to someone, you’re more likely to come into contact with their respiratory secretions, such as mucus from the upper respiratory tract. The flu virus can also live on the skin of someone who has the virus, when these respiratory droplets or other bodily fluids fall to the skin. When you come into contact with these fluids, you can be exposed to the flu virus and contract influenza.
On Surfaces
Occasionally, the flu can be spread when you touch a surface that has the virus on it, then touch your own eyes, nose or mouth, allowing the virus to enter your body. This is called surface transmission. The flu can survive for up to 48 hours on hard objects like doorknobs. It survives for a shorter time on cloth and other porous surfaces.
When You’re Contagious
After you’ve come into contact with the virus, you can develop symptoms anywhere from one to four days later. You can begin spreading the flu one day before symptoms appear. You’re contagious for up to seven days, but most likely to infect someone else in the first three to four days of illness.
Staying Ahead of the Flu
The best way to prevent the flu is by getting vaccinated with a flu vaccine and practicing good hygiene, including washing your hands frequently. To reduce your chances of contracting the flu:
Get vaccinated annuallyWash your hands frequentlyMinimize contact with infected people, where possibleStay home when you are sickAvoid touching your nose, mouth or eyes, particularly in publicLead an overall healthy lifestyle
Flu Season and COVID Prevention
During the COVID-19 pandemic, there has been a dramatic decrease in flu cases, especially during the 2020-2021 flu season.
Researchers believe that this is largely due to COVID-related precautions including social distancing affecting flu rates. Flu activity rose during the 2021-2022 flu season, but preliminary estimates from the CDC show that there were fewer hospitalizations and deaths than in previous flu seasons. However, as some of the COVID-related precautions have been lowered since then, researchers predict upcoming flu seasons to be more severe.
Summary
Influenza is primarily spread through airborne transmission via aerosols. These tiny particles are released when an infected person coughs, sneezes or talks and can float through the air for a long time. However, research indicates that some transmission of the flu happens from coming into contact with an infected surface.
A Word From Verywell
Scientists are still studying how, precisely, the flu is spread. However, they know that certain precautions—including getting vaccinated and frequently washing your hands—can reduce the risk for flu transmission. Many of the same precautions that people have adopted to prevent the spread of COVID can also reduce your risk of spreading or contracting influenza.
