Influenza a y b pdf

Getting lots of rest, eating a healthy diet, and drinking plenty of fluids helps your body fight the virus as well. An uncomplicated infection with either influenza A or influenza B can cause symptoms that last around one week.

Some people may still have a cough or feel fatigued after two weeks. Some influenza A subtypes can cause more severe disease than others. For example, in the recent past influenza A H3N2 viruses have been associated with more hospitalizations and deaths in children and the elderly than in other age groups, according to the CDC. In the past, it was thought that infection with influenza A was more severe than infection with influenza B.

However, a study in adults with influenza A and influenza B found they both resulted in similar rates of illness and death. Additionally, in a Canadian study looking at children 16 years old and younger, influenza B infection was associated with a higher risk for mortality than influenza A.

Influenza C is regarded as the least serious of the three types that humans can get. It typically produces a mild respiratory illness in adults. The CDC estimates that each year, from to , influenza infection resulted in between 9. Data for the to influenza season indicates that Among hospitalizations, The seasonal flu vaccine is developed many months in advance of flu season.

The viruses selected for the vaccine are based on research into which strains will likely be most common. Sometimes the circulating influenza viruses can mutate from one season to the next. Since experts must select the viruses to include in the vaccine months before flu season, there may not be a good match between the vaccine and the circulating viruses.

This can lead to a decrease in the effectiveness of the vaccine. But even when this happens, the vaccine still offers some protection. A quadrivalent vaccine protects against the same three viruses as the trivalent vaccine plus protection against an additional influenza B virus.

Influenza types A, B, and C can cause illness in humans. But types A and B cause seasonal epidemics of respiratory illness nearly every year. Influenza A typically causes the majority of illnesses during flu season. It has the potential to lead to pandemics due to its dynamic, faster changing nature and large host range. Both influenza A and B are extremely contagious and cause the same type of illness and symptoms.

You may not feel much like eating, but choosing the right foods to eat when you have the seasonal flu can help keep you hydrated and give your body…. The flu shot has been found to be safe for most people. Learn more about the ingredients in the vaccine. Esta es la imagen de un virus de influenza A. Existen 18 subtipos diferentes de hemaglutinina HA y 11 subtipos de neuraminidasa NA. Haga clic sobre la imagen para ampliarla. Hay cuatro tipos de virus de la influenza: A, B, C y D.

Los virus A y B de la influenza humana causan una epidemia estacional de la enfermedad conocida como temporada de influenza casi todos los inviernos en los Estados Unidos. Las infecciones por el virus de influenza tipo C por lo general causan una enfermedad leve y se cree que no causan epidemias humanas.

However, the proportion of influenza B viruses from each lineage that circulate can vary by geographic location and by season. Figure 2 — This image shows how influenza viruses are named.

The name starts with the virus type, followed by the place the virus was isolated, followed by the virus strain number often a sample identifier , the year isolated, and finally, the virus subtype. CDC follows an internationally accepted naming convention for influenza viruses. This convention was accepted by WHO in and published in February in the Bulletin of the World Health Organization, 58 4 see A revision of the system of nomenclature for influenza viruses: a WHO Memorandum pdf icon[ KB, 7 pages]external icon pdf icon external icon.

The approach uses the following components:. Getting a flu vaccine can protect against these viruses as well as additional flu viruses that are antigenically similar to the viruses used to make the vaccine.

Seasonal flu vaccines do not protect against influenza C or D viruses or against zoonotic animal-origin flu viruses that can cause human infections, such as variant or avian flu viruses.

In addition, flu vaccines will NOT protect against infection and illness caused by other viruses that also can cause influenza-like symptoms. There are many other viruses besides influenza that can result in influenza-like illness ILI that spread during flu season.

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. Types of Influenza Viruses. Minus Related Pages. Close This is a picture of an influenza flu A virus. What CDC Does. To receive weekly email updates about Seasonal Flu, enter your email address: Email Address.