Swine flu: preventing spread in the home and
community
This briefing material has been produced for those who work in healthcare
professions, the media and others who are looking for background understanding of
swine flu and/or those who are responsible for providing hygiene guidance to the
public on how to reduce the risks of spread of swine flu in their homes and in the
community.
What is swine influenza?
H1N1 swine influenza, or “swine flu”, is a highly contagious acute respiratory disease
of pigs, caused by swine influenza A viruses. The virus is spread among pigs by
aerosols and direct and indirect contact. Pigs can carry the virus without showing any
signs of the disease. Outbreaks in pigs occur all year round, but with increased
incidence in the autumn and winter in temperate zones. Many countries routinely
vaccinate pig populations against swine influenza. The disease is considered
endemic in the United States. Outbreaks in pigs have also been reported in North
and South America, Europe (including the UK, Sweden, and Italy), Africa (Kenya),
and in parts of eastern Asia including China and Japan. Swine flu cannot be caught
by eating pork meat.
Swine flu in humans
Swine flu viruses do not normally infect humans. Most commonly, where such
infections occur they are in persons with direct exposure to pigs (e.g. children near
pigs at a fair or workers in the swine industry). Person-to-person transmission is
known to occur but has been thought to be limited to close contacts and closed
groups of people. In 2007, WHO was notified of swine influenza cases from the
United States and Spain. In the past, CDC received reports of approximately one
human swine influenza virus infection every one to two years in the U.S., but from
December 2005 through to February 2009, increased numbers of cases of human
infection with swine influenza have been reported.
As of 26 April 2009, the Government of Mexico reported 18 laboratory confirmed
cases of swine influenza A/H1N1. Suspected cases were reported in 19 of the
country's 32 states. It is thought that the virus may have been involved in the deaths
of about 60 people, mostly in and around Mexico City. A new swine flu strain has
was confirmed in 16 of the deaths and 44 others are being tested. Most of those who
have died were young adults, rather than more vulnerable children and the elderly.
As of 26 April 2009, the United States Government has also reported 20 laboratory
confirmed human cases of swine influenza A/H1N1 (8 in New York, 7 in California, 2
in Texas, 2 in Kansas and 1 in Ohio). All 20 cases had mild Influenza-like illness with
only one requiring brief hospitalisation. No deaths have been reported.
The World Health Organization has confirmed that at least some of the cases
currently being reported are a new variant of the H1N1 strain of influenza type A.
H1N1 is the strain which causes seasonal outbreaks of flu in humans on a regular
basis. This latest version of H1N1 is different: because it contains genetic material
that is typically found in strains of the virus that affect humans, birds and swine.
The H1N1 (2009) 'swine flu' pandemic virus which emerged in Mexico in 2009 then
spread around the world causing mild/asymptomatic disease in the majority of cases
but severe illness and death in a small proportion of cases, particularly in more
vulnerable groups.
In August 2010 the WHO officially declared the H1N1(2009) pandemic over.
What are the symptoms of swine flu in humans?
The symptoms of swine flu in people are similar to the symptoms of regular human
seasonal influenza and include fever, lethargy, lack of appetite and coughing. Some
people with swine flu also have reported runny nose, sore throat, nausea, vomiting
and diarrhoea. Since typical clinical presentation of swine influenza infection in
humans resembles seasonal influenza and other acute upper respiratory tract
infections, in the past, most of the cases have been detected by chance through
seasonal influenza surveillance. Mild or asymptomatic cases may have escaped
recognition, therefore the true extent of this disease among humans is unknown.
In the past, human infection with swine influenza was generally mild but is known to
have caused severe illness such as pneumonia. For the 2009 outbreak in the United
States and Mexico however, the clinical pictures were different. None of the
confirmed cases in the United States had the severe form of the disease and the
patients recovered from illness without requiring medical care. In Mexico, some
patients reportedly had the severe form of the disease.
How is swine flu transmitted?
It is likely that the mode of transmission of swine flu is the same as that for seasonal
flu. However, the mode of transmission of colds and influenza remains highly
contentious. There are 3 possible routes of transmission:
Droplet transmission: occurs when the infected individual directly sprays large
droplets (droplets of size > 5µm) of infected mucous by coughing or sneezing, which
propels the droplets onto conjunctiva of the eye (the virus enters the tear fluid and
drains down a duct into the nose) or the lining of the nose of a susceptible host,
where the virus then infects the mucous membranes.
Airborne transmission: involves droplet nuclei (droplets of size < 5µm) and does
not require face-to-face contact with the infected individual. Droplet nuclei settle from
the air slowly and are respirable i.e. the virus can be drawn down directly into the
alveolar region of the lungs where they infect the tissue of the lungs.
Contact transmission involves hands and surfaces. Infected droplets of mucous are
deposited on surfaces either by settling of airborne droplets or being touched with
Page 2/6
contaminated fingers. An individual can pick up the virus if they touch a contaminated
surface or shake hands with an infected individual with contaminated hands. They
can then become infected if they rub their eyes or nose with contaminated hands
when the virus infects the nasal mucosa.
It is thought that seasonal flu is transmitted by all 3 pathways, but there is
considerable disagreement as to the relative importance of each pathway. Whereas
some investigators believe that droplet transmission is the major pathway for spread
of flu and airborne transmission is of minor importance, others maintain that the role
of droplet transmission has been overrated and that airborne transmission is a
potentially important transmission pathway in indoor environments. Flu can also be
spread via the hands by contact with objects that an infected person has
contaminated with infectious nose and throat secretions, although there is less
supporting evidence for this mode of spread than for colds.
Current WHO and ECDC recommendations on measures to reduce the spread of
influenza are based on the supposition that influenza mainly spreads from person-toperson by large droplets from an infected person coughing and sneezing, and by
contact transmission.
Understanding the relative importance of the different routes of transmission is key
for development of strategies for containing a flu pandemic in the early stages, when
a vaccine is not yet available. Recommending the use of face masks only makes
sense if airborne or droplet transmission are important. Handwashing promotion is
only worthwhile if contact transmission is significant. A 2007 analysis of measures
such as isolation, quarantine, social distancing, barriers, personal protection and
hygiene to prevent the spread of viruses such as influenza and SARS, indicated that
handwashing and wearing masks, gloves and gowns were effective individually in
preventing the spread of respiratory viruses, and were even more effective when
combined. Evidence that measures such as hand hygiene, can reduce spread of
influenza comes from the SARS outbreaks in Hong Kong, which coincided with the
latter part of the influenza season, when it was observed that, as extensive personal,
and community, public health measures took place, influenza case numbers fell
significantly, more so than usual for the time of year.
Is there a human vaccine to protect against swine influenza?
Influenza viruses change very quickly. The WHO selects vaccine viruses twice a year
for seasonal influenza protection, once for the northern hemisphere winter and
another for the southern hemisphere. The current seasonal influenza vaccine
produced, based on WHO recommendations, does not contain swine influenza virus.
It is possible that the currently available flu vaccines may give some, but only limited
protection against swine flu.
What drugs are available for treatment?
Two drugs commonly used to treat flu, Relenza and Tamiflu, seem to be effective at
treating cases that have occurred so far. However, the drugs must be administered at
an early stage to be effective. Use of these drugs may also make it less likely that
infected people will pass the virus on to others.
Page 3/6
Practical advice to prevent the risk of spread of infection
There are a number of things we can do which reduce the risks of spread of influenza
viruses. Avoidance of flu viruses is worthwhile, by keeping away from crowded,
poorly ventilated places wherever possible. Preventing the spread of flu germs
through good respiratory hygiene also reduces the risks of infection. Adopting good
hygiene measures in the home is particularly important when someone in the family
is already infected. Adults are able to infect others one day before getting symptoms
and up to one week after getting sick. Children can be infectious for even longer,
sometimes up to several weeks. This means that you can infect someone before you
know that you are sick as well as while you are sick.
To protect yourself from becoming infected at home and in the community
 Avoid close contact with people who appear unwell and who have fever and
cough.
 Keep away from crowded, poorly ventilated places wherever possible. Avoid
shaking hands with people when you meet with them.
 You can pick up the virus on your hands from surfaces which other people have
touched e.g. door handles, lift call buttons etc. Clean your hands frequently and
thoroughly, especially when you travelling around or in public places. Either:
 wash your hands thoroughly using soap and water. Make sure you use good
mechanical action and rinse your hands under clean running water to remove
any infected mucous. Make sure your hands are dry, as wet or moist hands are
more likely to spread germs.
 alternatively, if a washbasin is not available, use an alcohol gel or other suitable
waterless hand sanitiser* to clean your hands.
 Treat your hands as potentially contaminated and avoid touching your nose and
eyes.
 If someone leaves a tissue lying around on surfaces be aware that your hands will
be contaminated after touching it – so clean them immediately whenever possible.
Clean your hands after touching any suspect item.
 Practice good health habits including adequate sleep, eating nutritious food, and
keeping physically active.
What to do if you think you are infected
If you feel unwell, have a high fever, cough and/or sore throat:
 Stay at home, keep away from work, school or crowds as much as possible.
 Rest and take plenty of fluids.
 Practice “Good respiratory hygiene”:
 block coughs or sneezes, preferably with a tissue, or with your hands - but
remember they are now contaminated and could spread infection. Avoid
touching your nose as much as possible.
 use disposable tissues rather than a cotton handkerchief to blow your nose.
Dispose of tissues immediately and ‘safely’. DO NOT leave them lying around
for other people to pick up and become infected.
 wash your hands thoroughly using soap and water. Make sure you use good
mechanical action and rinse your hands under clean running water to remove
any infected mucous. Make sure your hands are dry, as wet or moist hands
are more likely to spread germs.
Page 4/6
 alternatively if a washbasin is not available, use an alcohol gel or other
suitable waterless hand sanitiser* to clean your hands.
Also:
 Think before you shake hands with anyone.
 Remember that you can transmit the virus to other people via computer
keyboards, TV remotes, telephones, door handles/tap handles etc. – so wash your
hands frequently
 Do not share your towels, facecloths, toothbrushes, eating utensils, etc. with other
family members.
If you are infected with influenza, stay indoors and keep contact with other people to
a minimum until seven days after your symptoms have improved and you have had
no fever for at least 48 hours.
If you need medical attention:
 Contact your doctor or healthcare provider before travelling to see them and
report your symptoms. Explain why you think you have swine influenza (for
example, if you have recently travelled to a country where there is a swine
influenza outbreak in humans). Follow the advice given to you for care.
 If it is not possible to contact your healthcare provider in advance, communicate
your suspicion of having swine influenza immediately upon arrival at the
healthcare facility.
 Take care to cover your nose and mouth during travel.
If you are caring for someone who is infected
If there is an infected person in the home:
 Try to provide the patient with a separate room in the house. If this is not
possible, keep the patient at least 1 metre in distance from others.
 Try to improve the air flow in the area where the patient is resting.
 Cover mouth and nose when caring for the patient.
 Clean your hands thoroughly after each contact with the patient. Either:
 wash your hands thoroughly using soap and water. Make sure you use good
mechanical action and rinse your hands under clean running water to remove
any infected mucous. Make sure your hands are dry, as wet or moist hands are
more likely to spread germs.
 alternatively if a washbasin is not available, use an alcohol gel or other suitable
waterless hand sanitiser* to clean your hands.
 Be aware that you and other family members could pick up infection from hand
contact surfaces around the home. Ensure that surfaces frequently touched by
different people are regularly cleaned and disinfected, e.g. door and cupboard
handles, toilet flush handles, wash basin taps, telephones, computer keyboards
and TV remotes. Where possible, use a bleach-based cleaner or other
disinfectant/cleaner that is capable of killing viruses* but take care with surfaces
such as computer keyboards which could become damaged.
 Cleaning cloths and sponges can readily spread flu germs from one surface to
another. Make sure that cloths are disinfected immediately after use using a
bleach disinfectant** and are thoroughly dried until the next use. Alternatively use
a disposable cloth or wipe to clean surfaces.
Page 5/6
 Wash any laundry (especially handkerchiefs, towels, face-cloths), used by those
who are infected, separately from other laundry, and at a higher temperature (at
least 60ºC) to ensure viruses are inactivated.
*Waterless hand sanitisers - (also called hand rubs) which are effective in
inactivating flu viruses on the hands are alcohol-based gels (or other products)
containing not less than 62% v/v alcohol. An alternative formulation which is effective
against flu viruses is also available which is a pyroglutamate/succinate buffering
system (pH 3.) in a topical foam formulation. The formulation also contains a polymer
that physically traps viral particles, reducing transfer from hands to the nasal mucosa
or conjunctiva of the eye. The effect is thus achieved through a combination of virus
entrapment and low pH inactivation of the virus. The action is sustained on the hands
for a few hours after application which helps protect against ongoing exposure to
respiratory viruses.
**Disinfectants and disinfectant cleaners - make sure you use a disinfectant or
disinfectant/cleaner such as a bleach-based product, which is active against
respiratory viruses. For more details on choosing the appropriate disinfectant, see
the IFH information sheet “Cleaning and disinfection: Chemical Disinfectants
Explained”. Consult the manufacturers’ instructions for information on the “spectrum
of action”, and method of use (dilution, contact time etc). For bleach (hypochlorite)
products, use a solution of bleach, diluted to 0.5% w/v or 5000ppm available chlorine.
Household bleach (both thick and thin bleach) for domestic use typically contains 4.5
to 5.0% w/v (45,000-50,000 ppm) available chlorine. Bleach/cleaner formulations
(e.g. sprays) are formulated to be used “neat” (i.e. without dilution). It is always
advisable, however, to check the label as concentrations and directions for use can
vary from one formulation to another.
Other References
1. In response to the need for education on respiratory hygiene, ECDC has produced
an “Influenza Communication Toolkit”. The aim is to assist health communicators
in devising communication campaigns to tackle seasonal influenza. The toolkit can
be found at:
http://www.ecdc.europa.eu/en/healthtopics/seasonal_influenza/communication_to
olkit/Pages/communication_toolkit.aspx
2. Colds, flu and other respiratory viruses in the home. International Scientific Forum
on Home Hygiene. The document can be found at:
http://www.ifh-homehygiene.org/factsheet/colds-flu-and-other-respiratoryinfections-home
Last updated 2015
Page 6/6