Vaccines are the best way to protect against some very serious infections. Influenza vaccine protects adults and children 6 months of age and older (for whom contraindications are not present) against influenza, which can be a serious illness for some people.

Influenza (commonly known as "the flu") is a serious, acute respiratory illness that is caused by a virus. People who get influenza have a cough, fever, chills, sore throat, headache, muscle aches and fatigue. Children can also get ear aches, nausea, vomiting, and diarrhea. Illness due to influenza usually lasts from three to five days, but can last longer. The cough and fatigue can persist for several weeks, making the return to full personal and work activities difficult.

People of any age can get the flu. Most people who get influenza are ill for only a few days. However, some people can become very ill/sick, and need to go to an emergency room or to the doctor's office.

Influenza spreads easily from infected persons through coughing and sneezing. It is also spread through direct contact with surfaces contaminated by the influenza virus, such as toys and eating utensils, and unwashed hands.

Avian Influenza A is an infection that is found in birds (e.g., poultry) and can be transmitted to humans. Given the small number of human cases, it appears that Avian Influenza A is not easily spread from infected poultry to humans or from human to human. The current evidence from the Avian Influenza A outbreaks in Asia, suggests that individuals involved in work activities with infected birds do run the risk of infection. The National Advisory Committee on Immunization (NACI) recommends trivalent influenza vaccine (TIV) for these individuals.

Preventing human influenza viral infection reduces the opportunity for human influenza virus and Avian Influenza A virus to come in contact and create a new strain. Therefore, the Ministry of Health and Long-Term Care (MOHLTC) recommends that all persons directly involved with live poultry and/or involved in the slaughtering process be vaccinated.

Protection from the vaccine develops by two weeks after the shot, and may last up to one year. The vaccine is about 70 to 90 percent effective in preventing influenza infection in healthy adults. In children, it is about 77 to 91 percent effective against influenza respiratory infection. In elderly people, the vaccine can prevent pneumonia and hospitalization in about 60 percent, and prevent death in about 80 percent. The viruses that cause influenza change often. Because of this, the influenza vaccine is updated each year.

People who receive the vaccine can still get influenza, but if they do, it is usually milder than it would have been without the shot.

Much of the illness caused by the flu can be prevented by annual flu vaccination. Anyone who wants to avoid getting the flu should consider getting vaccinated.

The vaccine is especially important for people in high-priority groups. These groups include people who are at high risk of complications from influenza and people who are most likely to spread the virus to the high-risk population. The high-priority groups are listed below :

Persons at risk for influenza-related complications :

• healthy children aged 6-23 months
• adults and children with chronic cardiac or pulmonary disorders
• people of any age who are residents of nursing homes or other chronic care facilities
• people 65 years of age and over
• adults and children with chronic medical conditions such as diabetes mellitus and other metabolic diseases, cancer, immunodeficiency (including HIV infection), immunosuppression (including that of transplant recipients), renal disease, anemia and hemoglobinopathy
• children and adolescents (aged 6 months to 18 yrs) with conditions treated for long periods with acetylsalicylic acid
• people at high risk of influenza complications embarking on travel to destinations where influenza is likely to be circulating
• pregnant and lactating women with chronic conditions such as those mentioned above

Persons capable of transmitting influenza to those at high risk for influenza-related complications :

• health care workers and other personnel who have significant contact with people in the high risk groups
• emergency medical service (EMS) workers
• practicing HCWs and support staff, in community and health care settings, with direct or indirect patient contact
• student HCWs, working in a clinical setting
• volunteers and staff in hospitals, nursing homes, homes for the aged, chronic care facilities/units, and retirement homes
• home care workers and volunteers
• staff and volunteers of public health units
• those providing regular child care to children ages 0 to 23 months, whether in or out of the home
• those providing services to those at high risk within closed or relatively closed settings (e.g. the crew on a ship)
• household contacts (including children) of people at high risk who either cannot be vaccinated or may respond inadequately to vaccination
• pregnant women in their third trimester should be vaccinated if they are expected to deliver during the influenza season as they will become household contacts to their newborns
• people who provide other essential community services
• people in direct contact with live poultry and/or involved in the slaughtering process

Healthy people should get vaccinated to protect themselves and their families from influenza and to avoid missing quality time (including holidays) with their families, to avoid losing time from work, and to avoid spreading the virus to others.

Influenza is much worse than a cold. Even healthy young people can become quite ill. You might bring the influenza virus home to a baby, older relative, or someone with a medical condition who could develop serious complications from influenza.

Children can also benefit from influenza vaccination. Influenza in preschoolers is associated with acute middle ear infections. Influenza may also lead to hospitalization in healthy children (particularly those under two years of age), as well as in children with underlying high-risk medical conditions. Children are also the main spreaders of the virus, in both the school and household settings. Influenza vaccination can decrease the incidence of middle ear infections associated with influenza, reduce school absenteeism and prevent community transmission of influenza.

The following persons should not get the influenza vaccine :

• infants under six months of age (the current vaccine is not recommended for this age group)
• anyone with a serious allergy (anaphylaxis) to eggs or egg products. A serious allergic reaction usually means that the person develops hives, swelling of the mouth and throat or has trouble breathing after eating eggs or egg products
• anyone who has a severe allergy to any component of the vaccine.(Please see product monographs)
• anyone who had a serious allergic reaction to a previous dose of the influenza vaccine.

Also :

• people with a history of Guillain-Barré Syndrome should consult their physician before getting the vaccine
• people who are acutely ill with a fever should usually wait until the fever goes down before being vaccinated.

The influenza vaccine, like any medicine, is capable of causing side effects, which can be either mild or, in few cases, severe. The risk of the vaccine causing serious harm is extremely small. Almost all people who get the flu vaccine have no serious problems.

Most people who get the vaccine have either no side effects, or mild side effects such as soreness, redness or swelling where the shot was given. Life-threatening allergic reactions are very rare. If they do occur, it is within a few minutes to a few hours after the vaccine.

Guillain-Barré Syndrome (or GBS) is a very uncommon disease that causes muscle paralysis and has been associated with certain infectious diseases. Overall, the risk of GBS occurring in association with vaccination is small. In comparison to the small risk of GBS, the risk of illness and death associated with influenza are much greater. Because it is not known whether influenza immunization increases the risk of recurrent GBS, it is recommended that persons who developed GBS within six to eight weeks of a previous vaccination should not be vaccinated at this time.

During the 2000/2001 season, a small number of people who received the vaccine developed a generally mild side effect called Oculo-Respiratory Syndrome, or ORS. The 2001 case definition of ORS is: the onset of bilateral red eyes and/or respiratory symptoms (cough, wheeze, chest tightness, difficulty breathing, difficulty swallowing, hoarseness or sore throat) and/or facial swelling occurring within 24 hours of influenza vaccination.

Individuals who have experienced ORS symptoms in the past may be safely re-immunized with influenza vaccine. For those who have had severe lower respiratory symptoms (wheeze, chest tightness, difficulty breathing), or any other symptom within 24 hours of influenza vaccination, that raise concern regarding the safety of re-immunization should seek expert medical advice.

No. The vaccine does not contain live viruses so you cannot get the flu from the vaccine. However, the vaccine will not protect you against colds and other respiratory illnesses that may be mistaken for influenza.

The vaccine is considered safe for pregnant women at all stages of pregnancy or those who are breastfeeding.

It is best to receive the influenza vaccine in October to mid-November before the flu season starts. This will give your body time to build protection against the influenza virus. It takes about two weeks after the vaccination to develop protection against influenza.

Because the influenza virus changes often, it is necessary to get the flu shot every year, for protection against the virus strains that are expected that year. Children younger than nine years of age, being vaccinated for flu for the first time, need two shots given at least one month apart. The second dose of influenza vaccine is not needed if the child has received one or more doses of vaccine during a previous influenza season.

You should call your doctor or see a doctor right away if you develop any of these symptoms within three days after the shot :

• trouble breathing, hoarseness, wheezing, cough, or chest tightness
• swelling of the mouth, throat or face
• paleness, weakness, a fast heart beat or dizziness
• hives
• bilateral red eyes
• any other unusual condition or serious reaction to the vaccine.

Your local public health unit should also be informed of serious reactions to any vaccine.

No. For the 2004-05 season, the influenza vaccine is again available free of charge to all Ontarians aged 6 months and older. The vaccine will be available through various sites including physicians' offices, community-based clinics administered by health units, hospitals, community health centres and pharmacies, and through employer-sponsored clinics at the workplace.

After you receive your vaccination, ensure that the doctor or nurse updates your personal immunization record, or "yellow card." Keep it in a safe place!

If you are looking for general information about influenza or the vaccine, the province's Universal Influenza Immunization Program or the location of a clinic near you, please call: 1-866-FLU'N YOU (1-866-358-6968) (TTY#1-800-387-5559).

If you have questions about the vaccine that are specific to your medical condition, you should ask your doctor or call your local public health unit.

October 2004

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