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Flu in Adults (cont.)

How Effective Is the Flu Shot?

  • Vaccination remains the most effective way to prevent the flu.
  • The effectiveness varies according to the age and health of the person receiving it and the closeness that it matches the strain that is circulating in any given year.
  • Numerous studies have shown that the flu shot can reduce hospitalizations from flu from 52% to 92% in various populations, such as adults with chronic health problems like diabetes, chronic lung disease, and heart disease as well as in older adults, infants, and pregnant women.
  • People who do get the flu despite receiving the flu shot may have a milder and shorter illness.

Flu Chemoprophylaxis

Annual influenza vaccination is the best way to prevent getting the flu, but for those who are at high risk and are unvaccinated, taking oseltamivir or zanamivir after exposure can also help prevent disease. Due to concerns that the flu virus may develop resistance to these drugs, widespread use of antiviral medication to prevent the flu is not recommended. In certain instances, for example, people with severe immunodeficiency who cannot receive flu vaccine or in whom it may not work, high-risk individuals exposed to flu, or residents of a health care facility or nursing home in which there is an influenza outbreak, may take oseltamivir or zanamivir for seven days to prevent the flu.

What Is Avian Flu, and Why Is It Important?

Influenza virus is one of the few viruses that infects humans and other species like birds and pigs. Waterfowl in the wild, such as geese and gulls, are natural species for influenza A strains. Some strains are highly pathogenic (very likely to cause disease) and highly contagious in birds and produce almost 100% death rates within days; these strains cause severe epidemics on poultry farms. Not only do they cause economic losses to farming, but they pose a potential for spreading to humans if the virus changes to a variant for which human infection becomes possible. This could lead to the ability to spread from human to human and could spark a global human pandemic with a highly lethal flu, so these events are closely tracked. H5 avian flu strains have occasionally spread to humans, with 50% mortality (death rate) and severe pneumonia, but human-to-human spread has been highly limited.

Medically Reviewed by a Doctor on 10/24/2017

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Read What Your Physician is Reading on Medscape

Influenza »

Influenza virus infection, one of the most common infectious diseases, is a highly contagious airborne disease that causes an acute febrile illness and results in variable degrees of systemic symptoms, ranging from mild fatigue to respiratory failure and death.

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