When is the flu virus infectious

Older children and adults with flu appear to be most contagious during the initial days of their illness but many people remain contagious for about 7 days. People who are hospitalized with severe disease and people with weakened immune systems can be contagious for 20 days or longer. Both COVID and flu can spread from person-to-person between people who are in close contact with one another within about 6 feet. Both are spread mainly by large and small particles containing virus that are expelled when people with the illness COVID or flu cough, sneeze, or talk.

These particles can land in the mouths or noses of people who are nearby and possibly be inhaled into the lungs.

In some circumstances, such as indoor settings with poor ventilation, small particles might be spread further than 6 feet and cause infections. Although most spread is by inhalation, it may be possible that a person can get infected by touching for example, shaking hands with someone who has the virus on their hands or by touching a surface or object that has virus on it, and then touching their own mouth, nose, or eyes.

Both flu viruses and the virus that causes COVID can be spread to others by people before they begin showing symptoms; by people with very mild symptoms; and by people who never experience symptoms asymptomatic people. This means the virus that causes COVID can quickly and easily spread to a lot of people and result in continual spreading among people as time progresses.

Those at highest risk include:. Most people who get flu will recover on their own in a few days to two weeks, but some people will experience severe complications , requiring hospitalization. Some of these complications are listed above. People at higher risk of complications or who have been hospitalized for COVID or flu should receive supportive medical care to help relieve symptoms and complications.

You may be able to pass on flu to someone else before you know you are sick, as well as while you are sick. To receive weekly email updates about Seasonal Flu, enter your email address:. Skip directly to site content Skip directly to page options Skip directly to A-Z link. Influenza Flu. Section Navigation.

Facebook Twitter LinkedIn Syndicate. How Flu Spreads. Minus Related Pages. The proportion of people who get sick from flu varies. You may be able to spread flu to someone else before you know you are sick, as well as while you are sick. The time from when a person is exposed and infected with flu to when symptoms begin is about 2 days, but can range from about 1 to 4 days.

Complications of flu can include bacterial pneumonia, ear infections, sinus infections and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes. Anyone can get flu even healthy people , and serious problems related to flu can happen at any age, but some people are at high risk of developing serious flu-related complications if they get sick. This includes people 65 years and older, people of any age with certain chronic medical conditions such as asthma, diabetes, or heart disease , pregnant women, and children younger than 5 years.

The first and most important step in preventing flu is to get a flu vaccine each year. Flu vaccine has been shown to reduce flu related illnesses and the risk of serious flu complications that can result in hospitalization or even death.

CDC also recommends everyday preventive actions like staying away from people who are sick, covering coughs and sneezes and frequent handwashing to help slow the spread of germs that cause respiratory nose, throat, and lungs illnesses, like flu. It is very difficult to distinguish flu from other viral or bacterial respiratory illnesses based on symptoms alone. There are tests available to diagnose flu.

More information is available: Diagnosing Flu. There are influenza antiviral drugs that can be used to treat flu illness. To receive weekly email updates about Seasonal Flu, enter your email address:. Skip directly to site content Skip directly to page options Skip directly to A-Z link.

Boling says. Blutinger says. Hindsight really is everything, Dr. Boling says: Once you develop symptoms of the flu, you have at least some clue of when your incubation period was. The only way to really have a tip-off of when your incubation period is when you're actually living through it is if you know you've been exposed to someone with the flu, Dr. But, unfortunately, most people are infected without knowing it. The bright side of all of this, if there even is such a thing, is that the proven methods to prevent the spread of COVID also work to lower your risk of both contracting and passing on the flu.

So, if you happen to catch the flu, wearing a mask while you're out and about and practicing social distancing should go a long way toward making sure your incubation period doesn't harm anyone else.