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. It's best to get the vaccine as soon as it's available. 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:3, 2
- Adults age 65 and older.
- Adults and children who
have long-term health problems or an
impaired immune system.
- Children 6 to 59 months of age.
- Women who will be
pregnant during the flu season.
- 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.
- People who live in nursing homes or long-term care centres.
- First Nations peoples.
The flu vaccine is also important for health care
workers and anyone who lives or works with a person who is at higher risk of
problems from the flu.
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 having severe symptoms and
complications is higher for:
- Children younger than 2 years of
age.
- Adults age 65 and older.
- Pregnant women.
- People who have
chronic obstructive pulmonary disease (COPD), other
lung diseases, or
heart failure.
- People who have a medical
condition (such as
acquired immunodeficiency syndrome [AIDS]) or who are
using a medicine that
impairs the immune system.
When To Call a Doctor
Call 911 or other emergency services if:
- You are having trouble breathing, or you 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.
- Your child is 6 months of age or younger and has a fever of 38°C (100.4°F) or higher.
- 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 do not go away, even with 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 find out the type of virus may be important if:
- The results may affect treatment decisions.
During a confirmed flu outbreak, though, testing may not be needed even if
treatment with an antiviral medicine 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 medicine. 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 medicine.
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
may help:
- 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.
Flu: Should I Take Antiviral Medicine?
If medicines are not used, contact your doctor if symptoms
of a complication develop.
Prevention
You can help prevent
influenza by getting immunized with an influenza
vaccine each year as soon as it's available.
Yearly immunization with
the
inactivated influenza vaccine (flu shot) or the
nasal spray flu vaccine prevents flu infection and its complications in
most people.
Most
healthy people ages 2 through 59 years can choose to get the
nasal spray form of the vaccine (such as FluMist) instead of the flu shot. The nasal
spray vaccine contains components of live viruses, so it should not be given to
people who have 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.
You should not
get the nasal spray if you:
- Have heart disease.
- Have lung
disease, including
asthma.
- Have
diabetes or kidney disease.
- Have a disease
or take a medicine that causes problems with your
immune system.
- Have a condition (such as a seizure disorder or cerebral palsy) that can cause breathing or swallowing problems.
- Are
pregnant.
- Are younger than age 18 and you take ASA or products with
ASA in them.
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, 7
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. These include beliefs that the flu is a minor illness or that the vaccine causes the flu. The
shot may cause
side effects, such as soreness or fever, but they are usually
minor and do not last long. And a type of flu shot (Intanza) is available that uses a much smaller needle than a regular flu shot. Also, it is injected into the skin instead of into a muscle. This usually causes less discomfort at the time of the shot. People age 18 years and older can get this shot. But it may not be available everywhere.
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.
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.
- Your child has ever had a seizure.
Because the nasal spray vaccine is more expensive than a
flu shot, it may not be covered by your provincial health plan or private health insurance plan. Check with your provincial or municipal health department or private
insurance company.
Almost every community has a program that offers flu vaccines
during the flu season. You also can get a flu vaccine during a
routine visit to a doctor or pharmacy. 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.
- Flu Vaccines: Should I Get a Flu Vaccine?
Other ways to reduce your risk for the flu or flu 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.8
Using antiviral medicines to prevent the flu
Two
antiviral medicines (oseltamivir and zanamivir) 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. The influenza medicines are usually given to people who are very sick with the flu or to those who are likely to have complications from the flu. But they may also be used for a person who has been sick with the flu for less than 48 hours. 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 (PHAC) 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.1, 9 This medicine has not worked against most
types of the flu virus. Amantadine does not protect against
influenza B. Be sure to talk with your doctor about the medicine that
is best for you.
- 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. Water, soup, fruit
juice, and hot tea with lemon 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.
- Over-the-Counter Medicine Precautions
- Quick Tips: Giving Over-the-Counter Medicines to Children
- To relieve body aches and headache, take
acetaminophen or ibuprofen.
- To help clear a stuffy nose, breathe moist air from a hot
shower or from a sink filled with hot water.
- Try a
decongestant 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. Before you use these medicines, check the label. They may not be safe for young children or for people who have certain health problems. Do not use medicated nasal
sprays or drops more often than directed, and don't use them for longer than 3
days.
- 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.
- If you have a dry, hacking cough, you can try an over-the counter cough medicine with dextromethorphan. Be careful with cough and cold medicines. They may not be safe for young children or for people who have certain health problems, so check the label first. If you do use these medicines, always follow the directions about how much to use based on age and weight.
- 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 anytime, 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 have 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 to 1½ days if given
within 48 hours of the first symptoms.4 These
medicines are not intended to substitute for getting a flu vaccine each
year. Rather, antiviral medicines may help control outbreaks and
prevent the spread of infection, especially in people at
high risk for flu complications.
The antiviral medicines
oseltamivir and zanamivir 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.1, 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.
- Flu: Should I Take Antiviral Medicine?
Medicine choices
Two types of antiviral medicines can treat influenza
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
having
complications.
But since most people who have the flu feel quite sick, 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.
Other Places To Get Help
Organizations
| Canadian Lung Association |
| 1750 Courtwood Crescent Street |
| Suite 300 |
| Ottawa, ON K2C 2B5 |
| Phone: | 1-888-566-5864
(613) 569-6411 |
| Fax: | (613) 569-8860 |
| Email: | info@lung.ca |
| Web Address: | www.lung.ca |
| |
The Canadian Lung Association focuses on research, education, and
the promotion of respiratory health. The organization offers educational
information on a variety of diseases and environmental threats, as well as
information on research, support groups, and resources for children and
teachers. Call to find a local office in your area. |
|
| Canadian Paediatric Society |
| 2305 Saint Laurent Boulevard |
| Ottawa, ON K1G 4J8 |
| Phone: | (613) 526-9397 |
| Fax: | (613) 526-3332 |
| Email: | info@cps.ca |
| Web Address: | www.cps.ca |
| |
The Canadian Paediatric Society (CPS) promotes quality health care
for Canadian children and establishes guidelines for paediatric care. The
organization offers educational materials on a variety of topics, including
information on immunizations, pregnancy, safety issues, and teen health. |
|
| 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 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. |
|
| Health Canada |
| A.L. 0900C2 |
| Ottawa, ON K1A 0K9 |
| Phone: | (613) 957-2991 |
| Fax: | (613) 941-5366 |
| Email: | info@hc-sc.gc.ca |
| Web Address: | www.hc-sc.gc.ca |
|
| 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. |
|
References
Citations
- 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.
- National Advisory Committee on Immunization (NACI) (2012). Statement on seasonal influenza vaccine for 2012–2013. Canada Communicable Disease Report, 38(ACS-4): 1–36. Also available online: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/12vol38/acs-dcc-4/index-eng.php#Toc324425256.
- 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.
- Fiore AE, et al. (2011). Antiviral agents for the treatment and chemoprophylaxis of influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR, 60(1): 1–25.
- 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.
- Eick AA, et al. (2011). Maternal influenza vaccination and effect on influenza virus infection in young infants.
Archives of Pediatrics and Adolescent Medicine, 165(2): 104–111.
- Leyer GJ, et al. (2009). Probiotic effects on cold and influenza-like symptom incidence and duration in children. Pediatrics, 124(2): e172–e179.
- 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.
Other Works Consulted
- American Academy of Pediatrics (2011). Recommendations for prevention and control of influenza in children, 2011–2012. Pediatrics, 128(4): 813–825.
- Bowels SK, Strang R (2011). Influenza. In C Repchinsky, ed., Therapeutic Choices, 6th ed., pp. 1379–1392. Ottawa: Canadian Pharmacists Association.
Credits
| By | Healthwise Staff |
|---|
| Primary Medical Reviewer | E. Gregory Thompson, MD - Internal Medicine |
|---|
| Specialist Medical Reviewer | Christine Hahn, MD - Epidemiology |
|---|
| Last Revised | September 20, 2012 |
|---|
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.
National Advisory Committee on Immunization (NACI) (2012). Statement on seasonal influenza vaccine for 2012–2013. Canada Communicable Disease Report, 38(ACS-4): 1–36. Also available online: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/12vol38/acs-dcc-4/index-eng.php#Toc324425256.
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.
Fiore AE, et al. (2011). Antiviral agents for the treatment and chemoprophylaxis of influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR, 60(1): 1–25.
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.
Eick AA, et al. (2011). Maternal influenza vaccination and effect on influenza virus infection in young infants.
Archives of Pediatrics and Adolescent Medicine, 165(2): 104–111.
Leyer GJ, et al. (2009). Probiotic effects on cold and influenza-like symptom incidence and duration in children. Pediatrics, 124(2): e172–e179.
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.
