Swine flu - Frequently Asked Questions

An outbreak that has killed more than 100 people in Mexico was caused by a new strain of swine influenza "that can attack anyone," Mexico's health minister said.

"It is a virus that mutated from pigs and then at some point was transmitted to humans," Jose Angel Cordova Villalobos said on April 24.

The outbreak, which Mexican authorities began reporting April 18, is being investigated by public health officials throughout North America.

So far, cases in Canada, the U.S. and Mexico suggest human-to-human transmission of this new swine flu virus occurred.

Canada's National Microbiology Laboratory in Winnipeg and the U.S. Centers for Disease Control confirmed that samples from Mexico were a new strain of swine flu.

In the meantime, the following is a summary of frequently asked questions about swine influenza prepared by the U.S. Centers for Disease Control and Prevention.

What is swine influenza?

Swine influenza (swine flu) is caused by type A influenza virus and gives pigs the flu. Swine flu viruses cause regular outbreaks of flu in pigs but death is infrequent. The viruses may circulate among pigs throughout the year, but most outbreaks occur during the late fall and winter months similar to outbreaks in humans. The classical swine flu virus (an influenza type A H1N1 virus) was first isolated from a pig in 1930.

How many swine flu viruses are there?

Like all flu viruses, swine flu viruses change constantly. Pigs can be infected by avian, human and swine influenza viruses. When influenza viruses from different species infect pigs, the viruses can reassort and new ones emerge that are a mix of swine, human and/or avian influenza viruses. Over the years, different variations of swine flu viruses have emerged. Right now, there are four main influenza type A virus subtypes that have been isolated in pigs: H1N1, H1N2, H3N2, and H3N1. However, most of the recently isolated influenza viruses from pigs have been H1N1 viruses.

Can humans catch swine flu?

Swine flu viruses do not normally infect humans. However, sporadic human infections with swine flu have occurred. Most commonly, these cases occur in persons with direct exposure to pigs, such as children near pigs at a fair or workers in the swine industry.

There have been documented cases of one person spreading swine flu to others. In 1988, an outbreak of apparent swine flu infection in pigs in Wisconsin resulted in multiple human infections, and although no community outbreak resulted, there was antibody evidence of virus transmission from the patient to health care workers who had close contact with the patient.

Why is this strain of flu causing so much concern?

It's a brand new mutation that's never been seen before. That's why it's not just hitting people in the highest risk groups — those over 65 and younger than two.

Flu is not usually a huge worry among the vast majority of healthy people because over the course of our lives, we are exposed to several flu strains. We develop some immunities. When we get the flu, we'll normally just feel really awful for a week or two. But when you have no immunities at all to a new strain, normally healthy people face as much of a risk as higher risk groups.

How does swine flu kill?

Swine flu — just like any other flu — is a respiratory infection. It exploits a weakened immune system to attack major organs — especially your lungs. When it gets into your lungs, it can lead to pneumonia, which can kill you. The flu can also cause secondary infections in your body — any of which can lead to failure of vital organs and death.

Can people catch swine flu from eating pork?

No. Swine flu viruses are not transmitted by food. You cannot get swine flu from eating pork or pork products. You won't get swine flu from handling uncooked pork either. You can get sick from putting uncooked or undercooked pork in your mouth, but you won't get swine flu.

It's also impossible to catch swine flu from eating fruits and vegetables imported from Mexico. Swine flu — like all influenza viruses — is not a food-borne illness.

How common is swine flu infection in humans?

In the past, the U.S. Centers for Disease Control and Prevention received reports of about one human swine flu virus infection every one to two years in the U.S., but from December 2005 through February 2009, 12 cases of human infection with swine flu have been reported. Five of the 12 cases occurred in patients who had direct exposure to pigs, six in patients reported being near pigs, and the exposure in one case was unknown.

What are the symptoms of swine flu in humans?

The symptoms of swine flu in people are expected to be 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 diarrhea.

How does swine flu spread?

Influenza viruses can be directly transmitted from pigs to people and from people to pigs. Human infection with swine flu viruses are most likely to occur when people are in close proximity to infected pigs, such as in pig barns and livestock exhibits at fairs.

Human-to-human transmission of swine flu can also occur. This is thought to occur in the same way as seasonal flu occurs in people, which is mainly person-to-person transmission through coughing or sneezing of people infected with the flu virus. People may become infected by touching something with flu viruses on it and then touching their mouth or nose.

What is known about human-to-human spread of swine flu?

In September 1988, a healthy 32-year-old pregnant woman was hospitalized for pneumonia and died eight days later. A swine H1N1 flu virus was detected. Four days before getting sick, she had visited a county fair swine exhibition where there was widespread flu-like illness among the pigs.

In follow-up studies, 76 per cent of swine exhibitors tested had antibody evidence of swine flu infection but no serious illnesses were detected among this group. Additional studies suggest that one to three health care personnel who had contact with the patient developed mild influenza-like illnesses with antibody evidence of swine flu infection.

How are human infections with swine flu diagnosed?

To diagnose swine influenza A infection, a respiratory specimen is ideally collected within the first four to five days of illness and sent to the CDC for testing.

What medications are available to treat humans with swine flu?

Four antiviral drugs are licensed for use in the United States: amantadine, rimantadine, oseltamivir and zanamivir. While most swine flu viruses have been susceptible to all four drugs, the most recent seven swine flu viruses isolated from humans are resistant to amantadine and rimantadine. Right now, the CDC recommends oseltamivir or zanamivir for the treatment and/or prevention of infection with swine flu viruses.

What other examples of swine flu outbreaks are there?

The most well known outbreak of swine flu was 1976 one among soldiers in Fort Dix, N.J. The virus caused illnesses in at least four soldiers and one death; all were previously healthy. The virus was transmitted in close contact at a basic training camp. It was thought to have circulated for a month and disappeared. The source of the virus, the exact time of its introduction into Fort Dix and factors limiting its spread and duration are unknown. The outbreak may have been caused by introduction of an animal virus into a stressed human population in close contact during the winter.


Source: Swine Influenza Top News

Is it safe to travel?

WHO is not recommending travel restrictions related to the outbreak of the influenza A(H1N1) virus. Today, international travel moves rapidly, with large numbers of individuals visiting various parts the world. Limiting travel and imposing travel restrictions would have very little effect on stopping the virus from spreading, but would be highly disruptive to the global community.

Influenza A(H1N1) has already been confirmed in many parts of the world. The focus now is on minimizing the impact of the virus through the rapid identification of cases and providing patients with appropriate medical care, rather than on stopping its spread internationally. Furthermore, although identifying the signs and symptoms of influenza in travellers can be an effective monitoring technique, it is not effective in reducing the spread of influenza as the virus can be transmitted from person to person before the onset of symptoms. Scientific research based on mathematical modelling indicates that restricting travel will be of limited or no benefit in stopping the spread of disease.

Historical records of previous influenza pandemics, as well as experience with SARS, have validated this point.

Travellers can protect themselves and others by following simple recommendations related to travel aimed at preventing the spread of infection. Individuals who are ill should delay travel plans and returning travellers who fall ill should seek appropriate medical care. These recommendations are prudent measures which can limit the spread of many communicable diseases and not only Influenza A(H1N1).

Source: Swine Influenza Top News

What can I do?

What are the recommendations for face masks?

If you are not sick you do not have to wear a mask. If you are caring for a sick person you should wear a mask. All home made masks should be cleansed regularly.

If you are sick, stay at home and avoid contact with people.

How can I protect myself and prevent illness?

Practise general preventive measures for influenza to prevent infection:

• avoid close contact with people who appear unwell and have fever and cough;
• wash your hands with soap and water thoroughly and often;
• practise good health habits including adequate sleep, eating nutritious food, and keeping physically active.

How do I care for an ill person at home?

• Separate the ill person from others, keeping the person at least 1 metre in distance from others.
• Cover your mouth and nose when caring for the ill person. Either commercial or homemade materials are fine, as long as they are disposed of or cleaned properly after use.
• Wash your hands with soap and water thoroughly after each contact with the ill person.
• Improve the air flow 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 there are infections follow additional advice from your national and local health authorities.

What should I do if I think I have the illness?

If you feel unwell, have high fever, cough or sore throat:

• Stay at home and keep away from work, school or crowds.
• Rest and take plenty of fluids.
• Cover your mouth and nose with disposable tissues when coughing and sneezing, and dispose of the used tissues properly.
• Wash your hands with soap and water often and thoroughly, especially after coughing or sneezing.
• Inform family and friends about your illness and try to avoid contact with other people.

What should I do if I need medical attention?

• Contact your doctor or healthcare provider before travelling to a health facility, and report your symptoms. Explain why you think you have influenza A(H1N1) (if you have recently travelled to a country where there is an outbreak in humans). Follow the advice given to you.
• If it is not possible to contact your healthcare provider in advance, communicate your suspicion of infection as soon as you arrive at the facility.
• Cover your nose and mouth during travel.

Source: Swine Influenza Top News

Vaccines for the new influenza A (H1N1)

Is an effective vaccine already available against the new influenza A(H1N1) virus?
No, but work is already under way to develop such a vaccine. Influenza vaccines generally contain a dead or weakened form of a circulating virus. The vaccine prepares the body’s immune system to defend against a true infection. For the vaccine to protect as well as possible, the virus in it should match the circulating “wild-type” virus relatively closely. Since this H1N1 virus is new, there is no vaccine currently available made with this particular virus. Making a completely new influenza vaccine can take five to six months.

What implications does the declaration of a pandemic have on influenza vaccine production?
Declaration by WHO of phase 6 of pandemic alert does not by itself automatically translate into a request for vaccine manufacturers to immediately stop production of seasonal influenza vaccine and to start production of a pandemic vaccine. Since seasonal influenza can also cause severe disease, WHO will take several important considerations such as the epidemiology and the severity of the disease when deciding when to formally make recommendations on this matter. In the meantime, WHO will continue to interact very closely with regulatory and other agencies and influenza vaccine manufacturers.

How important will influenza A(H1N1) vaccines be for reducing pandemic disease?
Vaccines are one of the most valuable ways to protect people during influenza epidemics and pandemics. Other measures include anti-viral drugs, social distancing and personal hygiene.

Will currently available seasonal vaccine confer protection against influenza A(H1N1)?
The best scientific evidence available today is incomplete but suggests that seasonal vaccines will confer little or no protection against influenza A(H1N1).

What is WHO doing to facilitate production of influenza A(H1N1) vaccines?
As soon as the first human cases of new influenza A(H1N1) infection became known to WHO, the WHO Collaborating Center in Atlanta (The Centers for Disease Control and Prevention (CDC) in the United States of America) took immediate action and began the work to develop candidate vaccine viruses. WHO also initiated consultations with vaccine manufacturers worldwide to facilitate the availability of all necessary material to start production of influenza A(H1N1) vaccine. In parallel, WHO is working with national regulatory authorities to ensure that the new influenza A(H1N1) vaccine will meet all safety criteria and be made available as soon as possible.

Why is WHO not asking vaccine manufacturers to switch production from seasonal vaccine to a influenza A(H1N1) vaccine yet?
WHO has not recommended stopping production of seasonal influenza vaccine because this seasonal influenza causes 3 million to 5 million cases of severe illness each year, and kills from 250 000 to 500 000 people. Continued immunization against seasonal influenza is therefore important. Moreover, stopping seasonal vaccine production immediately would not allow a pandemic vaccine to be made quicker. At this time, WHO is liaising closely with vaccine manufacturers so large-scale vaccine production can start as soon as indicated.

Is it possible that manufacturers produce both seasonal and pandemic vaccines at the same time?
There are several potential options which must be considered based on all available evidence.

What is the process for developing a pandemic vaccine? Has a vaccine strain been identified, and if so by whom?
A vaccine for the Influenza A(H1N1) virus will be produced using licensed influenza vaccine processes in which the vaccine viruses are grown either in eggs or cells. Candidate vaccine strains have been identified and prepared by the WHO Collaborating Center in Atlanta (The Centers for Disease Control and Prevention (CDC) in the United States of America)1. These strains have now been received by the other WHO Collaborating Centers which have also started preparation of vaccine candidate viruses. Once developed, these strains will be distributed to all interested manufacturers on request. Availability is anticipated by mid-May.

How quickly will influenza A(H1N1) vaccines be available?
The first doses of Influenza A(H1N1) vaccine could be available in five to six months from identification of the pandemic strain. The regulatory approval will be conducted in parallel with the manufacturing process. Regulatory authorities have put into place expedited processes that do not compromise on the quality and safety of the vaccine. Delays in production could result from poor growth of the virus strain used to make the vaccine.

How would manufacturers be selected?
There are currently more than a dozen vaccine manufacturers with licenses to produce influenza vaccines. Upon request, the vaccine strain will be available to each of them, as well as to other qualified vaccine manufacturers who are preparing to make influenza vaccine but do not yet have a licensed influenza vaccine.

What is the global manufacturing capacity for a potential influenza A(H1N1) pandemic vaccine? Is this the same as the global manufacturing capacity for H5N1?
The projections made for the production capacity of an vaccine for H5N1 cannot be automatically assumed to be the capacity to make an H1N1 vaccine. H5N1 and H1N1 viruses are different and the amount of antigen needed to make an effective H1N1 vaccines may be different than for H5N1. Therefore it is not possible to make a precise estimate. However, given these considerations, a conservative estimate of global capacity is at least 1 to 2 billion doses per year.

How is production capacity for influenza vaccines distributed geographically?
More that 90% of the global capacity today is located in Europe and in North America. However, during the past five years, other regions have begun to acquire the technology to produce influenza vaccines. Six manufacturers in developing countries have done so with technical and financial support from WHO.

What will be the storage requirements for influenza A(H1N1) vaccine?
The vaccine should be stored under refrigerated conditions at between 2°C and 8°C.

It has been impossible so far to develop vaccines for major killers such as HIV and malaria. How sure are we that there will not be scientific or other hurdles in developing an effective influenza A(H1N1) vaccine?
Typically, development of influenza vaccines has not posed a problem. Influenza vaccines have been used in humans for many years and are known to be immunogenic and effective. Each year seasonal influenza vaccines with varying composition are produced for the northern and southern hemisphere influenza seasons. Vaccine manufacturers will employ a number of different technologies to develop their vaccines. They will take advantage, notably, of novel approaches that were developed over the past years for H5N1 avian influenza vaccines. One key unknown is yield of vaccine virus production, since some strains grow better than others and the behavior of the new influenza A(H1N1) strain in manufacturers’ systems is not yet known. New recombinant technologies are under development, but have not yet been approved for use.

Will influenza A(H1N1) vaccines be effective in all population groups?
There are not data on this but there also is no reason to expect that they would not, given current information.

Will the influenza A(H1N1) vaccine be safe?
Licensed vaccines are held to a very high standard of safety. All possible precautions will be taken to ensure safety of new influenza A(H1N1) vaccines.

How can a repeat of the 1976 swine flu vaccine complications (Guillain-Barré syndrome) experienced in the United States of America be avoided?
Guillain-Barré syndrome is an acute disorder of the nervous system. It is observed following a variety of infections, including influenza. Studies suggest that regular seasonal influenza vaccines could be associated with an increased risk of Guillain-Barré syndrome on the order of one to two cases per million vaccinated persons. During the 1976 influenza vaccination campaign, this risk increased to around 10 cases per million vaccinated persons which led to the withdrawal of the vaccine.

Pandemic vaccines will be manufactured according to established standards. However, they are new products so there is an inherent risk that they will cause slightly differently reactions in humans. Close monitoring and investigation of all serious adverse events following administration of vaccine is essential. The systems for monitoring safety are an integral part of the strategies for the implementation of the new pandemic influenza vaccines. Quality control for the production of influenza vaccines has improved substantially since the 1970s.


Will it be possible to deliver new influenza A(H1N1) vaccine simultaneously with other vaccines?
Inactivated influenza vaccine can be given at the same time as other injectable vaccines, but the vaccines should be administered at different injection sites.

If the virus causes a mild pandemic in the warmer months and changes into something much more severe in, say, 6 months, will vaccines being developed now be effective?
It is too early to be able to predict changes in the influenza A(H1N1) virus as it continues to circulate in humans or how similar a mutated virus might be to the current virus. Careful surveillance for changes in the influenza A(H1N1) virus is ongoing. This close and constant monitoring will support a quick response should important changes in the virus be detected.

Will there be enough influenza A(H1N1) vaccine for everyone?
The estimated time to make enough vaccine to vaccinate the world's population against pandemic influenza will not be known until vaccine manufacturers will have been able to determine how much active ingredient (antigen) is needed to make one dose of effective influenza A(H1N1) vaccine.

In the past two years, influenza vaccine production capacity has increased sharply due to expansion of production facilities as well as advances in research, including the discovery and use of adjuvants. Adjuvants are substances added to a vaccine to make it more effective, thus conserving the active ingredient (antigen).


What is WHO's perspective on fairness and equity for vaccine availability?
The WHO Director-General has called for international solidarity in the response to the current situation. WHO regards the goal of ensuring fair and equitable access by all countries to response measures to be among the highest priorities. WHO is working very closely with partners including the vaccine manufacturing industry on this.

Who is likely to receive priority for vaccination with a future pandemic vaccine?
This decision is made by national authorities. As guidance, WHO will be tracking the evolution of the pandemic in real-time and making its findings public. As information becomes available, it may be possible to better define high-risk groups and to target vaccination for those groups, thus ensuring that limited supplies are used to greatest effect.

Will WHO be conducting mass influenza A(H1N1) vaccination campaigns?
No. National authorities will implement vaccination campaigns according to their national pandemic preparedness plans. WHO is exploring whether the vaccine can be packaged, for example, in multi-dose vials, to facilitate the rapid and efficient vaccination of large numbers of people.

Developing countries are very experienced in administering population-wide vaccination campaigns during public health emergencies caused by infectious diseases, including diseases like epidemic meningitis and yellow fever, as well as for polio eradication and measles control programmes.


How feasible will it be to immunize large numbers of people in developing countries against a pandemic virus?
Developing countries have considerable strategic and practical experience in delivering vaccines in mass campaigns. The main issue is not feasibility, but how to ensure timely access to adequate quantities of vaccine.


What is the estimated global number of doses of seasonal vaccine used annually?
The current annual demand is for less than 500 million doses per year.

Will seasonal influenza vaccine continue to be available?
At this time there is no recommendation to stop production of seasonal influenza vaccine.
Source: Swine Influenza Top News

Levels of pandemic alert

What does pandemic alert phase 5 mean?
According to WHO definitions of phases - the virus has caused sustained community level outbreaks in at least two countries in one WHO region. At phase 5 a pandemic is considered imminent.

What is sustained human to human transmission?
This occurs when three generations are involved - i.e. the virus has passed from person A to person B and then to person C.

What is the difference between a probable case and a confirmed case?
A probable case is one that shows the symptoms of influenza such as cough, fever, headache, chills and fatigue and either tests positive for type A influenza or is considered linked to another probable or confirmed case.
A confirmed case is one which tests positive in a laboratory for the influenza A(H1N1) virus.

At what point does WHO consider a pandemic to have started?
Phase 6, as defined by the WHO pandemic preparedness guidelines. However, during both phase 5 and phase 6, national and local actions to respond to the outbreak shift from preparedness to response at a global level. The goal of recommended actions during these phases is to reduce the impact of the pandemic on society.

Source: Swine Influenza Top News

About the disease

How do people become infected with influenza A(H1N1)?
Outbreaks in humans are now occurring from human-to-human transmission. When infected people cough or sneeze, infected droplets get on their hands, drop onto surfaces, or are dispersed into the air. Another person can breathe in contaminated air, or touch infected hands or surfaces, and be exposed. To prevent spread, people should cover their mouth and nose with a tissue when coughing, and wash their hands regularly.

What are the signs and symptoms of infection?
Early signs of influenza A(H1N1) are flu-like, including fever, cough, headache, muscle and joint pain, sore throat and runny nose, and sometimes vomiting or diarrhoea.

Regarding study of the first outbreak, have you received any feedback from the WHO team sent to Mexico to investigate the outbreak?
Teams are already sending epidemiological evidence but we will know more over the next few days.

Is there any confirmation of transmission between pigs and humans at this point?
No.

Is there any information on the economic impact of the outbreak so far?
No.

Why are we so worried about this pandemic possibility when thousands die every year from seasonal epidemics?
Seasonal epidemics occur every year and we are able to treat the virus with seasonal vaccines. A pandemic is a worldwide epidemic. It is a new virus and one to which the populations will have no immunity.

Source: Swine Influenza Top News