Good personal health and hygiene habits are reasonably effective in avoiding and minimizing influenza. Those below are some ways to prevent:
- Wash your hands often to help protect you from germs.
- Avoid close contact with people who are sick, if possible.
- Keep your distance from others when you are sick, to protect them from becoming infected.
- Stay home from work, school, and errands when you are sick, if possible, to help prevent others from catching your illness.
- Cover your mouth and nose with a tissue when coughing or sneezing.
- Keep your hands away from your eyes, nose, or mouth. Germs are often spread when you touch something that is contaminated with them and then touch your eyes, nose, or mouth.
Vaccination against influenza with a flu vaccine is strongly recommended for high-risk groups, such as children and the elderly. You can get the vaccine at your doctor's office or a local clinic, and in many communities at workplaces, supermarkets, and drugstores.
Vaccines can cause the immune system to react as if the body were actually being infected, and general infection symptoms (many cold and flu symptoms are just general infection symptoms) can appear, though these symptoms are usually not as severe or long-lasting as influenza.
You must get the vaccine every year because it changes. Scientists make a different vaccine every year because the strains of flu viruses change from year to year. Nine to 10 months before the flu season begins, they prepare a new vaccine made from inactivated (killed) flu viruses. Because the viruses have been killed, they cannot infect you. The vaccine preparation is based on the strains of the flu viruses that are in circulation at the time. It includes those A and B viruses (see section on types of flu viruses) expected to circulate the following winter.
Sometimes, an unpredicted new strain may appear after the vaccine has been made and distributed to doctors' offices and clinics. Because of this, even if you do get the flu vaccine, you still may get infected. If you do get infected, however, the disease usually is milder because the vaccine will still give you some protection.
It is possible to get vaccinated and still get influenza. The vaccine is reformulated each season for a few specific flu strains, but cannot possibly include all the strains actively infecting people in the world for that season. It takes about six months for the manufacturers to formulate and produce the millions of doses required to deal with the seasonal epidemics; occasionally, a new or overlooked strain becomes prominent during that time and infects people although they have been vaccinated (as by the H3N2 Fujian flu in the 2003–2004 flu season). It is also possible to get infected just before vaccination and get sick with the very strain that the vaccine is supposed to prevent, as the vaccine takes about two weeks to become effective.
How to produce the vaccines?
These vaccines can be produced in several ways; the most common method is to grow the virus in fertilised hen eggs. After purification, the virus is inactivated (for example, by treatment with detergent) to produce an inactivated-virus vaccine. Alternatively, the virus can be grown in eggs until it loses virulence and the avirulent virus given as a live vaccine. The effectiveness of these flu vaccines is variable. Due to the high mutation rate of the virus, a particular flu vaccine usually confers protection for no more than a few years. Every year, the World Health Organization predicts which strains of the virus are most likely to be circulating in the next year, allowing pharmaceutical companies to develop vaccines that will provide the best immunity against these strains. Vaccines have also been developed to protect poultry from avian influenza. These vaccines can be effective against multiple strains and are used either as part of a preventative strategy, or combined with culling in attempts to eradicate outbreaks.
Can the flu vaccine cause the problems or side effects?
The most dangerous side-effect is a severe allergic reaction to either the virus material itself, or residues from the hen eggs used to grow the influenza; however, these reactions are extremely rare. The flu vaccine may contain some egg protein, which can cause an allergic reaction if you are allergic to eggs.
The most common side effect in children and adults is soreness at the site of the vaccination. Other side effects, especially in children who previously have not been exposed to the flu virus, include fever, tiredness, and sore muscles. These side effects may begin 6 to 12 hours after vaccination and may last for up to 2 days.
Because the flu vaccine can cause problems, or side effects, in some people, you must talk with your health care provider before getting a flu vaccine shot or nasal spray flu vaccine.
Who should get the flu vaccine?
If you are in any of the following groups or live in a household with or provide care for someone who is, you should get the flu vaccine.
- You are 50 years of age or older
- You have chronic diseases of your heart, lungs, or kidneys
- You have diabetes
- Your immune system does not function properly
- You have a severe form of anemia
- You will be more than 3 months pregnant during the flu season
- You live in a nursing home or other chronic-care housing facility
- You are in close contact with infants or children up to 5 years of age
- Children from age 6 months up to their fifth birthday get the flu vaccine.