Education Materials

Mount Sinai Hospital is a University of Toronto patient care, teaching, and research centre.
Mount Sinai Hospital is a University of Toronto patient care, teaching, and research centre.

Frequently Asked Questions

» What is Influenza?

  • Influenza is a serious disease, which can be brought into hospital by staff, visitors, volunteers, students and patients.
  • An illness which occurs each year, usually between November and April. This year has seen an early onset of the disease, with two local nursing homes reporting outbreaks.
  • It is caused by a virus called influenza - three main types called Influenza A (H1N1), Influenza A(H3N2), and Influenza B.
  • All three types cause similar symptoms, which may include fever, headache, runny nose, cough and muscle aches.
  • Healthy adults may feel miserable for a few days, but usually recover uneventfully.
  • In the elderly or people with chronic illness, influenza can result in serious complications including pneumonia, a worsening of their underlying chronic illness (e.g. congestive heart failure) and death.

» How is Influenza Spread?

  • Both through the air and by contact with nose or throat secretions from an infected person. Transmission is easily accomplished by sneezing, coughing and talking.
  • As it is so easily spread, influenza can make many people ill in a short period of time.
  • Onset of symptoms range from 18 to 72 hours.

» What is the Influenza Vaccine?

  • The vaccine is made by purifying proteins from three different strains of the influenza virus.
  • Because influenza viruses are continuously mutating to avoid our immune systems, new vaccines are made up every year.
  • To remain protected from the influenza virus you need the new vaccine each year.
  • Protection develops about 2 weeks after receiving the vaccine.

» Will the Vaccine Stop me from Getting Ill?

  • The vaccine contains only noninfectious viruses, and therefore it cannot cause influenza.
  • Respiratory infections immediately following the vaccine represent coincidental illness and are not related to vaccination.
  • It will not protect you from other viruses, and you may still get other usual coughs and colds during the season, some of which can make you feel quite sick.

» Why Should I Take the Vaccine?

  • It will protect you from getting Influenza and from feeling ill.
  • It will protect you from getting influenza from patients in the hospital, getting sick and taking it home and giving it to your family and friends. Because influenza can be complicated by such illnesses as congestive heart failure and pneumonia, ill and older people with influenza may need to be admitted to hospital. Thus, the risk of getting influenza is higher in hospitals than other places.
  • It will prevent you from giving Influenza to your patients.
  • The Canadian National Advisory Committee on Immunization recommends that all health care workers be vaccinated in order to protect their patients from this disease.

» What are the Side Effects From the Vaccine?

  • About 1 in 4 people can get a sore arm following vaccination. This usually lasts for a few hours, but in some instances may last for a day or two.
  • Prophylactic acetaminophen, taken at the time of injection and repeated 6 hours later appears to decrease this effect.

» Is there Anyone who Should not get Vaccinated?

  • People who have had an allergic reaction to the influenza vaccine, or other vaccinations in the past should not get vaccinated unless they have been assessed by a physician and the influenza vaccine deemed to be safe.
  • People who are allergic to components of the influenza vaccine, should not be vaccinated. The exception to this is persons with egg allergies. It is safe to administer influenza vaccine to persons who are allergic to eggs.
  • The vaccine has not been tested in children < 6 months old (they are protected by their mother's antibody), and such children should not be vaccinated.
  • People who have had Guillian Barre Syndrome with onset within 6 weeks of a previous dose of influenza vaccine should not be vaccinated.

» I am Pregnant/Breastfeeding. Should I get Vaccinated?

  • The Canadian National Advisory Committee on Immunization recommends that all pregnant women with medical conditions that increase with complications from influenza be vaccinated.
  • The vaccine is safe in pregnancy, and there is no reason why you should not get it (indeed, you do not want to get influenza while you are pregnant).
  • However, many people who are pregnant wish, on general principle, not to take any medication that is not absolutely necessary. If you are pregnant, you should make the decision you feel most comfortable with.
  • The vaccine does not adversely affect the health of breastfeeding mothers or their infants.

» Can I get Fever, Aches and Pains from the Vaccine?

  • NO
  • Older vaccines could give you a mild fever and aches, however the new purified vaccines do not.
  • Remember, however, that the vaccine is given at a time of year when many people get sick from viruses, so that it is not uncommon for anyone to get infections at this time of year.

» Some doctors are saying that if you get vaccinated, you will stop building up natural immunity and be more likely to get sick later. Is this true?

  • There are no long term, randomized controlled trials to prove whether, in the long term, vaccination provides more or less protection.
  • It is true that often (but not always), immunity from vaccination decreases faster than that from natural infection.
  • In any given year you have about a 1 in 6 chance of getting infected with one of the three common circulating types of influenza virus. If you get infected, you will develop antibody and be immune to that particular virus strain, but not to others.
  • The Influenza vaccine routinely lets you develop antibodies to antigens from all three common circulating strains in any given year, therefore it is more likely that you will get better long term overall protection from vaccination than from natural infection.
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