NOT USED Influenza A (H1N1)

NOT USED Influenza A (H1N1)

Mondial Assistance continues to closely follow developments of the Swine flu virus (H1N1 virus), gathering extensive, practical and reliably-sourced information. Herein, we provide pertinent links for further reading and latest recommendations for precautionary measures and travelling to infected regions. We recommend you read this information for your own general knowledge, particularly if you are preparing to travel.

We will update this page regularly and are committed to keeping you well-advised. We also recommend that you consult the World Health Organisation website.

The flu, or influenza, is a frequent, acute respiratory illness caused by a variety of influenza viruses. It is at the origin of annual epidemics.

A few key figures:

  • In annual influenza epidemics 5-15% of the population are affected with upper respiratory tract infections. Hospitalisation and deaths mainly occur in high-risk groups (elderly, chronically ill). Although difficult to assess, these annual epidemics are thought to result in between three and five million cases of severe illness and between 250 000 and 500 000 deaths every year around the world;

  • The flu exists in three types of viruses: A, B and C;

  • Flu symptoms are non-specific and can lead to complications, particularly among people 65 years and older and in children under one year of age;

  • The best preventive measure against the flu is to get a flu vaccination. Vaccinations reduce flu-related deaths by 80% and hospitalisations by 50%.

Among the three types of existing viruses, the A virus is found in humans and also in ducks, geese, turkeys, chickens, pigs, horses and other animals. The B and C viruses are almost exclusively human. Only influenza A viruses can cause pandemics. There have been three major pandemics in the 20th century: in 1918 – 1919, 1957, and 1968.

Flu symptoms are non-specific but can sometimes lead to serious complications, such as respiratory infections, or chronic lung conditions, heart disease, kidney dysfunction or metabolic disorders.

The vaccination is considered to be the best flu preventive measure, and is strongly recommended each year before the flu season. The vaccination’s composition depends on the strain of viruses predicted at the time of the epidemic. The vaccine has few undesirable side effects - antibodies appear within an average of two weeks following the vaccination and remain present for several months afterwards.

Three anti-viral medications can be prescribed to prevent or help combat the flu: amantadine (mantadix), zanamivir (relenza) and oseltamavir (tamiflu). These medications are not considered alternatives to the vaccination, but can possibly be used as a complementary treatment in certain cases.

Swine influenza, or “swine flu”, is a highly contagious acute respiratory disease of pigs, caused by one of several swine influenza A viruses. Morbidity tends to be high and mortality low (1-4%). The virus is spread among pigs by aerosols, direct and indirect contact, and asymptomatic carrier pigs. Outbreaks in pigs occur year round, with an increased incidence in the autumn and winter in temperate zones. Many countries routinely vaccinate swine populations against swine influenza.

Swine influenza viruses are most commonly of the H1N1 subtype, but other subtypes are also circulating in pigs (e.g., H1N2, H3N1, H3N2). Pigs can also be infected with avian influenza viruses and human seasonal influenza viruses as well as swine influenza viruses. The H3N2 swine virus was thought to have been originally introduced into pigs by humans. Sometimes pigs can be infected with more than one virus type at a time, which can allow the genes from these viruses to mix. This can result in an influenza virus containing genes from a number of sources, called a "reassortant" virus. Although swine influenza viruses are normally species specific and only infect pigs, they do sometimes cross the species barrier to cause disease in humans.

Outbreaks and sporadic human infection with swine influenza have been occasionally reported. Generally clinical symptoms are similar to seasonal influenza but reported clinical presentation ranges broadly from asymptomatic infection to severe pneumonia resulting in death.

Since typical clinical presentation of swine influenza infection in humans resembles seasonal influenza and other acute upper respiratory tract infections, most of the cases have been detected by chance through seasonal influenza surveillance. Mild or asymptomatic cases may have escaped from recognition; therefore the true extent of this disease among humans is unknown.

Humans usually contract swine influenza from infected pigs, however, some cases lack contact history with pigs or environments where pigs have been located. Human-to-human transmission has occurred in some instances but was limited to close contacts and closed groups of people

Yes. Swine influenza has not been shown to be transmissible to people through eating properly handled and prepared pork (pig meat) or other products derived from pigs. The swine influenza virus is killed by cooking temperatures of 160°F/70°C, corresponding to the general guidance for the preparation of pork and other meat.

It is likely that most people, especially those who do not have regular contact with pigs, do not have immunity to swine influenza viruses that can prevent the virus infection. If a swine virus establishes efficient human-to human transmission, it can cause an influenza pandemic. The impact of a pandemic caused by such a virus is difficult to predict: it depends on virulence of the virus, existing immunity among people, cross protection by antibodies acquired from seasonal influenza infection and host factors.

There are no vaccines that contain the current swine influenza virus causing illness in humans. It is not known whether current human seasonal influenza vaccines can provide any protection. Influenza viruses change very quickly. It is important to develop a vaccine against the currently circulating virus strain for it to provide maximum protection to the vaccinated people. This is why WHO needs access to as many viruses as possible in order to select the most appropriate candidate vaccine virus.

There are two classes of such medicines, 1) adamantanes (amantadine and remantadine), and 2) inhibitors of influenza neuraminidase (oseltamivir and zanamivir).

Most of the previously reported swine influenza cases recovered fully from the disease without requiring medical attention and without antiviral medicines.

Some influenza viruses develop resistance to the antiviral medicines, limiting the effectiveness of treatment. The viruses obtained from the recent human cases with swine influenza in the United States are sensitive to oselatmivir and zanamivir but resistant to amantadine and remantadine.

Information is insufficient to make recommendations on the use of the antivirals in treatment of swine influenza virus infection. Clinicians should make decisions based on the clinical and epidemiological assessment and harms and benefits of the treatment of the patient2. For the ongoing outbreak of the swine influenza infection in the United States and Mexico, national and local authorities are recommending use oseltamivir or zanamivir for treatment of the disease based on the virus’s susceptibility profile.

Even though there is no clear indication that the current human cases with swine influenza infection are related to recent or ongoing influenza-like disease events in pigs, it would be advisable to minimize contact with sick pigs and report such animals to relevant animal health authorities.

Most people are infected through prolonged, close contact with infected pigs. Good hygiene practices are essential in all contact with animals and are especially important during slaughter and post-slaughter handling to prevent exposure to disease agents. Sick animals or animals that died from disease should not be undergoing slaughtering procedures. Follow further advice from relevant national authorities.

Swine influenza has not been shown to be transmissible to people through eating properly handled and prepared pork (pig meat) or other products derived from pigs. The swine influenza virus is killed by cooking temperatures of 160°F/70°C corresponding to the general guidance for the preparation of pork and other meat.

In the past, human infection with swine influenza was generally mild but is known to have caused severe illness such as pneumonia For the current outbreaks in the United States and Mexico however, the clinical pictures have been different. None of the confirmed cases in the United States have 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.

To protect yourself, practice general preventive measures for influenza:

  • Avoid close contact with people who appear unwell and who have fever and cough. 

  • Wash your hands with soap and water frequently and thoroughly. 

  • Practice good health habits including adequate sleep, eating nutritious food, and keeping physically active.

If there is an ill person at home:

  • Try to provide the ill person a separate section in the house. If this is not possible, keep the patient at least 1 meter in distance from others. 

  • Cover mouth and nose when caring for the ill person. Masks can be bought commercially or made using the readily available materials as long as they are disposed of or cleaned properly. 

  • Wash your hands with soap and water thoroughly after each contact with the ill person.

  • Try to improve the air flow in the area where the ill person stays. Use doors and windows to take advantage of breezes. 

  • Keep the environment clean with readily available household cleaning agents.

If you are living in a country where swine influenza has caused disease in humans, follow additional advice from national and local health authorities.