The typical flu season can fall anywhere between October and May, and
usually peaks sometime between January and March. Because the timing of the
flu season can be unpredictable, health care providers are encouraged to
begin vaccinating as soon as the seasonal vaccine is available. Ideally,
vaccination should take place by the end of October. However, it is never
too late to get vaccinated. As long as flu is circulating, vaccination is
recommended. It will be take about two weeks from the time of vaccination
for you to be protected. The influenza vaccine does not protect against
other respiratory illnesses.
Frequently Asked Questions (Seasonal Flu)
What is influenza (also called flu)?
The flu is a contagious respiratory illness caused by influenza
viruses that infect the nose, throat, and lungs. It can cause mild
to severe illness, and at times can lead to death. The best way to
prevent the flu is by getting a flu vaccine each
year. An average of 2,800 North Dakotans are reported as having
lab-identified flu every year--the number of actual cases occuring
in North Dakota each year is likely much higher.
What are the signs and symptoms of flu?
People who have the flu often feel some or all of these signs and
* It is important to note that not everyone with flu
will have a fever.
Fever* or feeling feverish/chills
Runny or stuffy nose
Muscle or body aches
Fatigue (very tired)
What about the stomach flu?
The "stomch flu" is a misleading term. Typically, influenza
virus is not the cause of stomach bugs.
Vomiting and diarrhea are rare but possible symtoms of influenza,
seen only in small children. Vomiting and diarrhea are
slightly more common in children with the 2009 A H1N1 pandemic
strain than other strains of influenza. However, these symptoms are
typically accompanied by other influenza symptoms that are not
secondary symptoms of vomiting and diarrhea. For example, body aches
that are not abdominal cramps or the abdominal soreness you may feel
after vomiting. An illness characterized by fever, nausea and
vomiting is likely not influenza, and should not be considered
How does flu spread?
Most experts believe that flu viruses spread mainly by
droplets made when people with flu cough, sneeze or talk.
These droplets can land in the mouths or noses of people who are
nearby. Less often, a person might also get flu by touching a
surface or object that has flu virus on it and then touching their
own mouth, eyes or possibly their nose.
How long is someone contagious if they have the flu?
You may be able to pass the flu to someone else before you
know you are sick, as well as while you are sick. Most healthy
adults may be able to infect others beginning 1 day before
symptoms develop and up to 5 to 7 days after
becoming sick. Some people, especially young children and
people with weakened immune symptoms, might be able to infect others
for an even longer time.
How can I prevent the flu?
The single best way to prevent the flu is to get a flu vaccine each
season. There are two types of flu vaccines:
“Flu shots” — inactivated vaccines (containing killed
virus) that are given with a needle. There are five flu shots being
produced for the United States market now.
The regular seasonal flu shot is “intramuscular” which means
it is injected into muscle (usually in the upper arm). It
has been used for decades and is approved for use in people
6 months of age and older, including healthy people, people
with chronic medical conditions and pregnant women. Regular
flu shots make up the bulk of the vaccine supply produced
for the United States. This year, flu shots come in either
quadrivalent or trivalent forms. Trivalent vaccine protects
against two types of influenza A virus and one type of
influenza B virus. Quadrivalent vaccines protect against the
same three strains as the trivalent vaccine and also include
protection against an additional B strain.
A hi-dose, intramusular vaccine for people 65 and older.
This trivalent vaccine is thought to help boost the immune
response in older people.
An intradermal vaccine for people 18 to 64 years of age
which is injected with a needle into the “dermis” or skin.
This vaccine is trivalent.
An intramuscular, trivalent vaccine that is made in cell
culture and has low egg content. This vaccine is approved
for people 18 and older.
An intramuscular, trivalent vaccine that is egg free. This
vaccine is approved for people 18-49.
The nasal-spray flu vaccine — a vaccine made with live, weakened
flu viruses that is given as a nasal spray (sometimes called
LAIV for “Live Attenuated Influenza Vaccine”). The viruses in
the nasal spray vaccine do not cause the flu. LAIV is approved
for use in healthy* people 2 to 49 years of age who are not
pregnant. All LAIV is quadrivalent.
Flu vaccination is recommended for everyone 6 months and older. Talk
to a health care professional about which vaccine is right for you.
After vaccination, it takes about two weeks for your body to develop
protection against the flu. Flu vaccines will not protect
against flu-like illnesses caused by non-influenza viruses.
In addition to vaccination, you can help prevent the spread of
influenza by washing your hands often, staying home when you are ill
and taking influenza antivirals if they have been perscribed to you.
When should I get vaccinated?
Influenza Fact Sheets
Copyright 2006 North Dakota Department of Health