When Flu SpreadsMost healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick. Children and some people with weakened immune systems may pass the virus for longer than 7 days.
In the United States, flu season occurs in the fall and winter. While influenza viruses circulate year-round, most of the time flu activity peaks between December and February, but activity can last as late as May.
What causes death from flu?
The same CID study found that children are most likely to get sick from flu and that people 65 and older are least likely to get sick from influenza. Median incidence values (or attack rate) by age group were 9.3% for children 0-17 years, 8.8% for adults 18-64 years, and 3.9% for adults 65 years and older.
The committee recommended that the quadrivalent formulation of cell- or recombinant based influenza vaccines for the U.S. 2020-2021 influenza season contain the following: an A/Hawaii/70/2019 (H1N1) pdm09-like virus; an A/HongKong/45/2019 (H3N2)-like virus; a B/Washington/02/2019- like virus (B/Victoria lineage);
These viruses spread seasonally each year because of a phenomenon known as antigenic drift: They evolve just enough to evade human immune systems, but not enough to develop into completely new versions of the virus. The H3N2 subtype causes the most disease each year.
Answer: Influenza is a virus that's spread from person to person. It originates, actually, among birds and other animals such as pigs, and new viral strains of influenza come to this country and to Europe from Southeast Asia.
What to expect with the flu
- Days 1–3: Sudden appearance of fever, headache, muscle pain and weakness, dry cough, sore throat and sometimes a stuffy nose.
- Day 4: Fever and muscle aches decrease. Hoarse, dry or sore throat, cough and possible mild chest discomfort become more noticeable.
- Day 8: Symptoms decrease.
How long will you be contagious? For most flu viruses, that window is about a week, starting from a day before your symptoms appear, to six or seven days afterward. For colds, even people who are feeling better can spread the virus to others for up to three weeks.
Unlike type A flu viruses, type B flu is found only in humans. Type B flu may cause a less severe reaction than type A flu virus, but occasionally, type B flu can still be extremely harmful. Influenza type B viruses are not classified by subtype and do not cause pandemics.
How long does the flu last? As harsh as the flu can be, the good news is that most people feel much better within one to two weeks. Most healthy adults become contagious the day before symptoms develop (which makes it trickier to prevent from spreading).
When to go to the ER for flu symptomsDifficulty breathing or shortness of breath. Pain or pressure in the chest or abdomen. Sudden dizziness or frequent dizzy spells. Confusion.
You're considered high risk and should see a doctor at the first signs of the flu if: you are age 65 or older. you have a chronic medical condition (such as asthma, diabetes, or heart disease)
In this Article
- Stay home and get plenty of rest.
- Drink plenty of fluids.
- Treat aches and fever.
- Take care of your cough.
- Sit in a steamy bathroom.
- Run the humidifier.
- Try a lozenge.
- Get salty.
Most people with the flu have mild illness and do not need medical care or antiviral drugs. If you get sick with flu symptoms, in most cases, you should stay home and avoid contact with other people except to get medical care.
In the past, it was thought that infection with influenza A was more severe than infection with influenza B. However, a 2015 study in adults with influenza A and influenza B found they both resulted in similar rates of illness and death.
The states with the highest amount of activity are Alabama, Arkansas, Georgia, Mississippi, Nevada, South Carolina, and Texas. The flu mortality rate also climbed — 5.2 percent of deaths were linked to pneumonia and influenza (P&I), whereas 4.9 percent were linked to P&I the week prior.
