Topic Overview
What is influenza (flu)?
Influenza (flu) is a
viral infection. People often use the term "flu" to
describe any kind of mild illness, such as a cold or a
stomach virus, that has symptoms like the flu. But the
real flu is different. Flu symptoms are usually worse than a cold and last
longer. The flu usually does not cause vomiting or diarrhea in adults.
Most
flu outbreaks happen in late fall and winter.
What causes the flu?
The flu is caused by
influenza viruses A and B. There are different strains of the flu
virus every year.
What are the symptoms?
The flu causes a fever,
body aches, a headache, a dry cough, and a sore or dry throat. You will
probably feel tired and less hungry than usual. The symptoms usually are the
worst for the first 3 or 4 days. But it can take 1 to 2 weeks to get completely
better.
It usually takes 1 to 4 days to get symptoms of the flu
after you have been around someone who has the virus.
Most people
get better without problems. But sometimes the flu can lead to a bacterial
infection, such as an
ear infection, a
sinus infection, or
bronchitis. In rare cases, the flu may cause a more
serious problem, such as
pneumonia.
Certain people are at higher
risk of problems from the flu. They include young children, pregnant women,
older adults, and people with long-term illnesses or with
impaired immune systems that make it hard to fight
infection.
How is the flu diagnosed?
Your doctor will ask you
about your symptoms and examine you. This usually gives the doctor enough
information to find out if you have the flu, especially if many cases of a
similar illness have occurred in the area and the local health unit
reports a flu outbreak.
In some cases, the doctor may do a blood
test or take a sample of fluid from your nose or throat to find out what type
of flu virus you have.
How is it treated?
Most people can treat flu
symptoms at home. Home treatment includes resting, drinking plenty of fluids,
and taking medicine to lower your fever.
If you think you have the
flu, your doctor may be able to give you medicine that can make the symptoms
milder. But you need to start taking it within 2 days of your first
symptoms.
Can the flu be prevented?
You can help prevent the
flu by getting the flu vaccine every year. The best time to get the vaccine is
in the fall, just before the start of flu season. You can get the
vaccine as a shot or in a spray that you breathe in through your nose.
Canada's National Advisory Committee on Immunization (NACI) recommends that everyone 6 months old and older should get a flu vaccine. The
vaccine is especially important for people who are at higher risk of problems
from the flu, including:1, 2
- People who are age 65 or older. People age
65 or older are the most likely to have problems from the flu.
- Adults and children who
have long-term health problems or an
impaired immune system.
- People who live in nursing homes
or long-term care centres.
- People who have a
weak immune system.
- Women who will be
pregnant during the flu season.
- Children 6 to 23 months of age.
- Children who are 24 months to 18 years old who use long-term ASA
treatment.
- People who are obese with a body mass index (BMI) of 40 or more.
- First Nations peoples.
- Healthy children ages 2 to 4 years old.
The flu vaccine is also recommended for health care
workers and anyone who lives or works with a person who is at higher risk of
problems from the flu. Your doctor can help you decide if the flu vaccine is a
good choice for you.
The vaccine usually prevents most cases of
the flu. But even if you do get the flu after you've had the vaccine, your
symptoms will be milder and you'll have less chance of problems from the flu.
You cannot get the flu from the flu vaccine.
Frequently Asked Questions
Learning about influenza (flu): | |
Being diagnosed: | |
Getting treatment: | |
Ongoing concerns: | |
Taking care of yourself: | |
Cause
The flu is caused by the
influenza virus. Doctors classify the virus as
influenza type A and type B, each of which includes several subtypes or
strains. Type A is usually responsible for the annual outbreaks that typically
occur in the late fall and early winter.
The influenza virus
changes often, so having flu caused by one strain does not give you full
immunity to other strains.
- Widespread outbreaks of the flu usually follow
significant changes (called antigenic shifts) in the virus and occur about
every 10 years. People who get the flu tend to become much sicker when a shift
in the flu virus occurs.
- Minor changes in the virus (called antigenic drifts) occur nearly
every year.
The virus is spread from person to person through:
- Direct contact, such as shaking hands.
- Small droplets that form when a person sneezes or
coughs.
- Contact with objects such as handkerchiefs that have been
in contact with fluids from an infected person's nose or throat.
When are you contagious?
If you are infected with the flu, you are most likely to pass it to someone else from 1 day before symptoms start and up to 7 days after
symptoms develop. Children may be infectious for longer than 7 days after symptoms start.
Symptoms usually develop 1 to 4 days after you are
infected. Because symptoms may not develop for a couple of days, you may pass
the flu to someone before you know you have it.
Symptoms
The symptoms of
influenza (flu) appear suddenly and often
include:
- Fever of
38°C (100°F) to
40°C (104°F), which can reach
41°C (106°F) when symptoms
first develop. Fever is usually continuous, but it may come and go. Fever may
be lower in older adults than in children and younger adults. When fever is
high, other symptoms usually are more severe.
- Body aches and muscle
pain (often severe), commonly in the back, arms, or
legs.
- Headache.
- Pain when you move your
eyes.
- Fatigue, a general feeling of sickness (malaise), and loss of
appetite.
- A dry cough, runny nose, and dry or sore throat. You may
not notice these during the first few days of the illness when other symptoms
are more severe. As your fever goes away, these symptoms may become more
evident.
Influenza usually does not cause symptoms in the stomach or
intestines, such as vomiting and diarrhea.
Other conditions have symptoms similar to the flu, such as the common cold, bacterial
infections, and infectious
mononucleosis.
What Happens
Influenza (flu) usually comes on suddenly. In many
cases people can pinpoint the hour when symptoms started. Symptoms develop 1 to
4 days after you are infected, and they include:
- Fever, which lasts for about 3 days. Fever is
usually slightly lower on the 2nd and 3rd days but may last up to 8
days.
- Cough, runny nose, and sore throat, which become more
noticeable as fever and other symptoms decrease. These symptoms usually last 3
to 4 days after the fever goes down. A dry, hacking cough may linger for up to
10 days after other symptoms are gone.
Complete recovery may take 1 to 2 weeks or longer. Fatigue
and weakness can last for several weeks.
Complications of
influenza may develop in anyone, but they are much more likely in older adults
and people who have other health problems, especially heart and lung
diseases.
What Increases Your Risk
Anyone exposed to an
influenza (flu) virus can become infected. These
viruses are contagious and spread easily among people in groups, such as in
nursing homes, hospitals, shelters, schools, and day cares. Working, visiting,
or living in any of these areas increases your risk of getting the flu.
The risk of developing severe symptoms and
complications is higher for:
When To Call a Doctor
Call 911 or other emergency services if:
- A baby younger than 3 months has a high
fever.
- You are having trouble breathing or feel very short of
breath.
- You have a severe headache or stiff neck and are confused
or having trouble staying awake.
Call your doctor if:
- You have an extremely high fever.
- Your fever
lasts for longer than 3 days.
- You are finding it harder and harder
to breathe.
- Wheezing develops.
- New pain develops or
pain localizes to one area, such as an ear, the throat, the chest, or the
sinuses.
- Symptoms persist in spite of home
treatment.
- Symptoms become more severe or frequent.
Watchful Waiting
In most healthy people, the
flu will go away in 5 to 7 days, although fatigue can
last much longer. Although you may feel very sick, home treatment is usually
all that is needed. If it is flu season, you may just want to treat your
symptoms at home. Watch closely for
symptoms of a bacterial infection, such as nasal
drainage that changes from clear to coloured after 5 to 7 days and symptoms that
return or get worse.
Early treatment (within 48 hours of your
first symptoms) with antiviral medicines may reduce the severity of influenza
and may prevent serious flu-related complications.4
Babies, older adults, and people who have chronic health problems are more
likely to have complications from the flu, and they may need to see a doctor
for care beyond home treatment. But not all antiviral medicines work against
all strains of the flu. Talk to your doctor if you think you may need an
antiviral medicine.
Call your doctor if you think your symptoms
are caused by something other than the flu.
Who To See
Your family doctor, general practitioner, or your child's pediatrician can diagnose and treat the flu.
A doctor who specializes in treating infectious diseases
may be needed if the diagnosis is not clear or if severe complications
develop.
To prepare for your appointment, see the topic Making the Most of Your Appointment.
Examinations and Tests
Doctors can diagnose
influenza (flu) using your symptoms alone if many
cases of a similar illness have occurred in the community and if the local
health unit has confirmed a flu outbreak.
Tests to confirm
you have the flu and to determine the type of virus may be important if:
- The results may affect treatment decisions.
During a confirmed flu outbreak, however, testing may not be needed even if
treatment with an antiviral medication is being considered.
- In
addition to flu-like symptoms, you have any unusual symptoms that suggest
another condition.
- Health authorities have not identified any other
cases of flu in your area.
Testing may involve blood tests (rarely used) or a
culture to identify the virus. Some cultures take 24
to 48 hours for results, so they will not help your doctor decide whether to
prescribe an antiviral medication. A rapid flu test is now available that gives
results in 30 minutes. Although this test is not 100% accurate, it can be
useful when deciding whether to use an antiviral medication.
Treatment Overview
In most healthy people,
influenza (flu) will go away in 5 to 7 days. The worst
symptoms usually last 3 to 4 days. Home treatment to ease symptoms and prevent
complications is usually all that is needed.
Antiviral medicines
can be taken to:
- Reduce the severity and duration of symptoms
caused by infection with influenza A or B virus.
- Shorten the length
of the illness.
- Control outbreaks of the flu in nursing
homes.
- Reduce the spread of the virus to people at high risk for
severe
complications of the flu (high-risk groups).
- Reduce complications from the flu.
People at high risk of complications are encouraged to
contact a doctor within 48 hours of their first symptoms to find out whether
they need medicine to shorten the illness. They also should call a doctor to
receive medicine if they have been exposed to the flu. For more information,
see:
Flu: Should I Take Antiviral Medicine?
If medicines are not used, contact your doctor if symptoms
of a complication develop.
What To Think About
Yearly immunization with
the
inactivated influenza vaccine (flu shot) or the
nasal spray flu vaccine prevents flu infection and its complications in
most people. The nasal spray vaccine is approved for use by healthy people who are 2 to 59
years old. People with certain health conditions should not get the nasal spray vaccine. For more information, talk with your doctor.
Before getting a flu vaccine, talk to your doctor if:
- You ever had a serious allergic reaction to eggs or to a previous dose of influenza vaccine.
- You have had
Guillain-Barré syndrome.
The yearly immunization rate is typically low for people
younger than 65 who are at high risk of developing the flu. All people in
high-risk groups and those who could transmit the virus to them because of
regular contact are strongly encouraged to get the flu vaccine.
Almost every community has a program that offers flu vaccines at low cost
during the fall months. You also can get a flu vaccine during a
routine visit to a doctor during the same months. Many health clinics have set
hours at the start of the flu season for people to get flu vaccines without needing
to make an appointment.
To help you decide if the flu vaccine is
right for you, see:
- Flu Vaccines: Should I Get a Flu Vaccine?
Although antiviral medicines sometimes prevent the flu,
they do not work in the same way as a yearly immunization and should not
replace a flu shot or dose of the nasal spray vaccine.
Prevention
You can help prevent
influenza by getting immunized with an influenza
vaccine each year, ideally in the fall.
The
inactivated influenza vaccine commonly known as the "flu shot," is given by
injection. Most people ages 6 months and older can get the flu shot. This form of the vaccine effectively prevents most cases of the flu,
although success rates vary according to age, health status, and how closely
the virus strains contained in the vaccine match those that are circulating
through the population.
Most
healthy people ages 2 through 59 years can choose to get the
nasal spray form of the vaccine (FluMist) instead of the flu shot. The nasal
spray vaccine contains components of live viruses, so it should not be given to
people with certain long-term (chronic) health conditions, such as heart or
lung problems. Close contacts of these people in high-risk categories can be
given either type of vaccine, with one rare exception. Immunization with the
inactivated virus (flu shot) is preferred over the nasal spray vaccine for
close contacts of people with severely
impaired immune systems during times when a protected
environment is needed. This avoids the risk of transmitting an active flu virus
from the nasal spray vaccine. If the nasal spray vaccine is used, contact with
anyone in this high-risk group should be avoided for 7 days. For close contacts
of people in all other high-risk categories, vaccination with either the flu
shot or the nasal spray is considered safe.
Even if a flu vaccine does not prevent the
flu, it can reduce the severity of flu symptoms and decrease the risk
of complications. Studies have found that the flu shot
results in fewer days missed from work and fewer visits to a doctor for
respiratory infections, and it reduces the number of people who develop
complications from the flu, such as
pneumonia.5 And the flu vaccine can help protect the babies of women who got the vaccine while they were pregnant.6
In
spite of these results, many people choose not to get a flu vaccine. Some do not
get the vaccine because of
myths they believe about the flu or the vaccines. The
flu shot may cause
side effects in some people, but they are usually
minor and do not last long.
Before getting a flu vaccine, talk to your doctor if:
- You ever had a serious allergic reaction to eggs or to a previous dose of influenza vaccine.
- You have had
Guillain-Barré syndrome.
Because the nasal spray vaccine is more expensive than a
flu shot, it may not be covered by your provincial health plan or private insurance plan. Check with your
provincial or municipal health department or insurance company.
For help deciding if the flu vaccine is
right for you, see:
- Flu Vaccines: Should I Get a Flu Vaccine?
Other ways to reduce your risk of getting the flu or developing complications
Increase your chance of staying healthy by:
- Washing your hands often, especially
during winter months when the flu is most common.
- Keeping your
hands away from your nose, eyes, and mouth. Viruses are most likely to enter
your body through these areas.
- Eating a healthy and
balanced diet.
- Getting regular
exercise.
- Not smoking. Smoking irritates the lining of your nose,
sinuses, and lungs, which may make you susceptible to complications of the
flu.
- Taking probiotics. One study has shown that taking probiotics helps prevent influenza symptoms and reduce antibiotic use in children.7
Using antiviral medicines to prevent the flu
Two
antiviral medicines (zanamivir and oseltamivir) can help prevent the flu caused by
influenza A and B viruses. These medicines may also reduce the length of the
illness if they are given no more than 48 hours after the first symptoms.
During a flu outbreak, these medicines may be given at the same time as a flu
vaccine and for 2 weeks after while your body produces
antibodies to protect you from the virus. These
medicines are taken by mouth (pill) or inhaled into the lungs (inhaler).
The antiviral medicine
amantadine has been used to prevent flu caused by influenza A.
But for the past few years the Public Health Agency of Canada and the U.S. Centers for Disease Control and Prevention
(CDC) have advised doctors not to use this medicine to treat or prevent the
flu.8, 9 This medicine has not worked against most
types of the flu virus, including
influenza B. Be sure to talk with your doctor about the medicine that
is best for you.
For more information, see:
- Flu: Should I Take Antiviral Medicine?
Home Treatment
If you have
influenza, you can expect the illness to go away on
its own in about 7 to 10 days. In the meantime, you can take steps to feel
better:
- Get extra rest. Bedrest can help you feel
better. It will also help you avoid spreading the virus to others.
-
Drink plenty of fluids to replace those lost from fever. Fluids also ease a
scratchy throat and keep nasal mucus thin. Hot tea with lemon, water, fruit
juice, and soup are all good choices.
- If fever is uncomfortable,
sponge your body with lukewarm water to reduce fever. Do not use cold water or ice.
Lowering the fever will not make your symptoms go away faster, but it may make you more comfortable. You
may also take acetaminophen or ibuprofen to lower fever. Follow all instructions on the label. If you give
medicine to your baby, follow your doctor’s advice about what amount to give. Do not give ASA to anyone younger than 20 because of the risk of Reye syndrome. For more information about medicine safety, see the
topics Over-the-Counter Medicine Precautions and Quick Tips: Giving Over-the-Counter Medicines to Children.
- To relieve body aches and headache, take
acetaminophen or ibuprofen.
- Try a
decongestant or nasal spray if your main symptom is a
stuffy nose. Look for a single-ingredient decongestant that contains
phenylephrine. If nasal drainage is thick, a decongestant that contains
guaifenesin may help keep it thin and draining. Do not use medicated nasal
sprays or drops more often than directed, and don't use them for longer than 3
days. Before you give decongestant medicines to a child, check the label. These medicines are not recommended for children younger than age 6.
- To help clear a stuffy nose, breathe moist air from a hot
shower or from a sink filled with hot water.
- Avoid antihistamines.
They do not treat flu symptoms and may make nasal drainage
thicker.
- If the skin around your nose and lips becomes sore from
repeated rubbing with tissues, apply a bit of petroleum jelly to the area.
Using disposable tissues that contain lotion also may help.
- Use
cough drops or plain, hard candy to help ease coughing.
- Take a
non-prescription cough medicine that contains dextromethorphan if you develop a
dry, hacking cough. Some products contain a high percentage of alcohol. Use
them with caution. Before you give cough medicines to a child, check the label. These medicines are not recommended for children younger than age 6.
- Elevate your head at night with an extra pillow if
coughing keeps you awake.
- Avoid smoking and breathing second-hand smoke. This is good
advice any time, but it is especially important when you have a respiratory
infection like a cold or the flu.
Call your doctor if:
- Your symptoms improve but then seem to get
worse again.
- You develop symptoms of a bacterial infection, such as
a new or worse cough that produces yellow, green, rust-coloured, or bloody
mucus; persistent fever, ear pain, sore throat, sinus pain, or productive
cough; or nasal drainage that changes from clear to coloured after 7 to 10
days.
Medications
Some antiviral medicines reduce the
severity and shorten the duration of
influenza (flu) symptoms by 1 or 1½ days if given
within 48 hours of the first symptoms.4 These
medicines are not intended to substitute for getting a flu immunization each
year. Rather, antiviral medicines are important for controlling outbreaks and
preventing the spread of infection, especially in people at
high risk for developing flu complications.
The antiviral medicines
zanamivir and oseltamivir are used to prevent and treat influenza A and B
infections. They can reduce the severity and shorten the duration of flu
symptoms.10 Amantadine has been used
to help prevent and treat the flu caused by influenza A (but not influenza B)
infection. But for the past few years the Public Health Agency of Canada (PHAC) and the U.S. Centers for Disease Control and
Prevention (CDC) have advised doctors not to use amantadine to
treat or prevent the flu.9 This medicine has not
worked against most types of the flu virus. It is important to talk with your
doctor about the medicine that is best for you.
For more
information, see:
- Flu: Should I Take Antiviral Medicine?
Medication Choices
Two types of antiviral medicines can treat influenza
infections:
- Oseltamivir or Zanamivir (used to treat
and prevent influenza A and B infections)
- Amantadine (used to prevent or treat
influenza A infections)
What To Think About
The effectiveness of antiviral
medicines can vary from year to year. Some years a medicine may not work
against the types of influenza virus causing symptoms. Your doctor can help you
decide whether antiviral medicines are likely to help you.
Most
people do not need antiviral medicines. They recover from influenza without
developing
complications.
But given how sick most
people are when they have the flu, some people may choose to take medicine even
if they are at low risk for complications.
You cannot prevent the
flu or make yourself feel better faster by taking:
- Antibiotics. For more information, see the
topic
Using Antibiotics Wisely.
- Large doses of
vitamins and minerals, such as vitamin C or zinc.
- Herbal remedies,
such as echinacea.
Surgery
Influenza cannot be treated with surgery.
Other Treatment
No other treatment is
available for
influenza.
Other Places To Get Help
Organizations
| KidsHealth for Parents, Children, and
Teens |
| 4600 Touchton Road East, Building 200 |
| Suite 500 |
| Jacksonville, FL 32246 |
| Phone: | (904) 232-4100 |
| Fax: | (904) 232-4125 |
| Web Address: | www.kidshealth.org |
| |
This Web site is sponsored by Nemours Foundation. It has
a wide range of information about children's health, from allergies and
diseases to normal growth and development (birth to adolescence). This Web site
offers separate areas for kids, teens, and parents, each providing
age-appropriate information that the child or parent can understand. You can
sign up to get weekly e-mails about your area of interest. |
|
| Public Health Agency of Canada
(PHAC) |
| 130 Colonnade Road |
| A.L. 6501H |
| Ottawa, ON K1A 0K9 |
| Phone: | Telephone numbers for PHAC vary by region. For your regional number, go to the listing on the PHAC website at www.phac-aspc.gc.ca/contac-eng.php. |
| Web Address: | www.phac-aspc.gc.ca/index-eng.php |
| |
The Public Health Agency of Canada (formerly the
Population and Public Health Branch of Health Canada) is primarily responsible
for policies, programs, and systems relating to disease prevention, health
promotion, disease surveillance, community action, and disease control. |
|
| U.S. Centers for Disease Control and Prevention
(CDC) |
| 1600 Clifton Road |
| Atlanta, GA 30333 |
| Phone: | 1-800-CDC-INFO (1-800-232-4636) |
| TDD: | 1-888-232-6348 |
| Email: | cdcinfo@cdc.gov |
| Web Address: | www.cdc.gov |
| |
The U.S. Centers for Disease Control and Prevention (CDC) is
an agency of the U.S. Department of Health and Human Services. The CDC works
with state and local health officials and the public to achieve better health
for all people. The CDC creates the expertise, information, and tools that
people and communities need to protect their health—by promoting health,
preventing disease, injury, and disability, and being prepared for new health
threats. |
|
| U.S. National Institute of Allergy and Infectious Diseases
(NIAID), National Institutes of Health |
| NIAID Office of Communications and Government Relations |
| 6610 Rockledge Drive, MSC 6612 |
| Bethesda, MD 20892-6612 |
| Phone: | 1-866-284-4107 toll-free |
| Phone: | (301) 496-5717 |
| Fax: | (301) 402-3573 |
| TDD: | 1-800-877-8339 |
| Web Address: | www.niaid.nih.gov |
| |
The U.S. National Institute of Allergy and Infectious
Diseases conducts research and provides consumer information on infectious and
immune-system-related diseases. |
|
References
Citations
- National Advisory Committee on Immunization (NACI) (2010). Statement on seasonal trivalent inactivated influenza vaccine (TIV) for 2010–2011.
Canada Communicable Disease Report, 36(ACS-6): 1–49.
Also available online:
http://origin.phac-aspc.gc.ca/publicat/ccdr-rmtc/10vol36/acs-6/index-eng.php.
- National Advisory Committee on Immunization (NACI)
(2006). Canadian Immunization Guide, 7th ed., pp. 1–372.
Ottawa: Public Health Agency of Canada. Also available online:
http://publications.gc.ca.
- Centers for Disease Control and Prevention (2010). Prevention and control of influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2010. MMWR, 59(RR-08): 1–62. Also available online: http://www.cdc.gov/mmwr/pdf/rr/rr5908.pdf. [Erratum in MMWR, 59(31): 993. Also available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5931a6.htm.]
- Jefferson T (2009). Influenza, search date June 2008.
Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.
- Nichol KL, et al. (2007). Effectiveness of influenza
vaccine in the community-dwelling elderly. New England Journal of Medicine, 357(14): 1373–1381.
- Zaman K, et al. (2008). Effectiveness of maternal influenza
immunization in mothers and infants. New England Journal of Medicine, 359(15): 1555–1564.
- Leyer GJ, et al. (2009). Probiotic effects on cold and influenza-like symptom incidence and duration in children. Pediatrics, 124(2): e172–e179.
- Public Health Agency of Canada (2009). National influenza treatment guidelines: Interim options for clinicians considering influenza antivirals in the context of changing patterns of resistance, 2008-09 season. Available online: http://www.phac-aspc.gc.ca/influenza/vac_antiv/nitg_ldni-eng.php.
- Centers for Disease Control and Prevention (2006). CDC Health Alert: CDC Recommends Against the Use of Amantadine and Rimantadine for the Treatment or Prophylaxis of Influenza in the United States During the 2005–06 Influenza Season. Available online:
http://www.cdc.gov/flu/han011406.htm.
- Cooper NJ, et al. (2003). Effectiveness of
neuraminidase inhibitors in treatment and prevention of influenza A and B:
Systematic review and meta-analyses of randomised controlled trials.
BMJ, 326(7401):1235.
Credits
| By | Healthwise Staff |
|---|
| Primary Medical Reviewer | E. Gregory Thompson, MD - Internal Medicine |
|---|
| Primary Medical Reviewer | Brian D. O'Brien, MD - Internal Medicine |
|---|
| Specialist Medical Reviewer | Christine Hahn, MD - Epidemiology |
|---|
| Last Revised | August 3, 2011 |
|---|
National Advisory Committee on Immunization (NACI) (2010). Statement on seasonal trivalent inactivated influenza vaccine (TIV) for 2010–2011.
Canada Communicable Disease Report, 36(ACS-6): 1–49.
Also available online:
http://origin.phac-aspc.gc.ca/publicat/ccdr-rmtc/10vol36/acs-6/index-eng.php.
National Advisory Committee on Immunization (NACI)
(2006). Canadian Immunization Guide, 7th ed., pp. 1–372.
Ottawa: Public Health Agency of Canada. Also available online:
http://publications.gc.ca.
Centers for Disease Control and Prevention (2010). Prevention and control of influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2010. MMWR, 59(RR-08): 1–62. Also available online: http://www.cdc.gov/mmwr/pdf/rr/rr5908.pdf. [Erratum in MMWR, 59(31): 993. Also available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5931a6.htm.]
Jefferson T (2009). Influenza, search date June 2008.
Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.
Nichol KL, et al. (2007). Effectiveness of influenza
vaccine in the community-dwelling elderly. New England Journal of Medicine, 357(14): 1373–1381.
Zaman K, et al. (2008). Effectiveness of maternal influenza
immunization in mothers and infants. New England Journal of Medicine, 359(15): 1555–1564.
Leyer GJ, et al. (2009). Probiotic effects on cold and influenza-like symptom incidence and duration in children. Pediatrics, 124(2): e172–e179.
Public Health Agency of Canada (2009). National influenza treatment guidelines: Interim options for clinicians considering influenza antivirals in the context of changing patterns of resistance, 2008-09 season. Available online: http://www.phac-aspc.gc.ca/influenza/vac_antiv/nitg_ldni-eng.php.
Centers for Disease Control and Prevention (2006). CDC Health Alert: CDC Recommends Against the Use of Amantadine and Rimantadine for the Treatment or Prophylaxis of Influenza in the United States During the 2005–06 Influenza Season. Available online:
http://www.cdc.gov/flu/han011406.htm.
Cooper NJ, et al. (2003). Effectiveness of
neuraminidase inhibitors in treatment and prevention of influenza A and B:
Systematic review and meta-analyses of randomised controlled trials.
BMJ, 326(7401):1235.
