FAQ on Influenza A(H1N1)

Source: World Health Organization 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. Use of antiviral drugs against influenza A(H1N1) For what purposes can antiviral drugs be used against influenza A(H1N1)? So far most people who have contracted the new A (H1N1) virus have experienced influenza-like symptoms (such as sore throat, cough, runny nose, fever, malaise, headache, joint/muscle pain) and recovered without antiviral treatment. Antiviral drugs may reduce the symptoms and duration of illness, just as they do for seasonal influenza. They also may contribute to preventing severe disease and death. Influenza A (H1N1) is a new virus and only a small number of people with the infection have been treated for it with antiviral drugs. WHO is in touch with public health authorities and clinicians in affected countries and is gathering information about how effective the drugs are. To which antiviral drugs does this influenza virus respond? There are two classes of antiviral drugs for influenza: inhibitors of neuraminidase such as oseltamivir and zanamivir; and adamantanes, such as amantadine and rimantadine. Tests on viruses obtained from patients in Mexico and the United States have indicated that current new H1N1 viruses are sensitive to neuraminidase inhibitors, but that the viruses are resistant to the other class, the adamantanes. Could the virus become resistant to oseltamivir and zanamivir? Resistance can develop to antiviral drugs used for influenza. Therefore, WHO and its partners are monitoring antiviral drug resistance. Under what circumstances should antiviral drugs be administered? Antiviral drugs are to be used according to national pandemic influenza preparedness plans. Public health authorities in some countries have decided to treat patients likely to have this disease as a part of public health measures. Where antiviral drugs are available for treatment, clinicians should make decisions based on assessment of the individual patient's risk. Risks versus benefits should also be evaluated on a case by case basis. What is WHO doing about getting antiviral drugs to countries as preparation for a pandemic? WHO’s first priority is to provide an emergency stock of antiviral drugs to countries that have no or insufficient stock of the drugs and lack the capacity to procure these drugs themselves. WHO is also working with Member States, donors and other groups that have stockpiles and are willing to share these with WHO for distribution to countries in need. Which drug will be provided, and how much of it does WHO have available? WHO had a global stockpile of approximately 5 million adult treatment courses of oseltamivir. Part of this stockpile has already been distributed through the WHO Regional Offices, which are handling allocation and distribution. WHO is currently distributing the remaining 3 million adult treatment courses of this stockpile to developing countries in need. WHO continues to assess needs and to work with manufacturers to secure more donations of antivirals. More antiviral drugs will be distributed once these donations are received. Which countries will receive the drug, and how will they be selected? WHO has arranged the first deployment of antiviral drugs from the WHO stockpile to 72 countries. Priority was given to vulnerable countries, taking into consideration national manufacturing and procurement capacity. As necessary, other countries will be supported through regional office stockpiles. What if the initial emergency deployment turns out to be inadequate? WHO is in discussion with manufacturers regarding the potential need for scaling up production. It is WHO’s understanding that manufacturers have plans for producing large numbers of treatments quickly. WHO will work on behalf of its Member States to secure further antivirals as needed, either through donations or purchase at the lowest possible price. 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. 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 a 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). 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. Travel Is it safe to travel? WHO is not recommending travel restrictions related to the outbreak of the influenza A(H1N1) virus. Today, global travel is commonplace and large numbers of people move around the world for business and leisure. 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 global response now focuses 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. Although identifying signs and symptoms of influenza in travellers can help track the path of the outbreak, it will not reduce 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 shows that restricting travel would be of limited or no benefit in stopping the spread of disease. Historical records of previous influenza pandemics, as well as experience with SARS, validate this. Does WHO recommend screenings at country entry and exit points to detect if ill people are travelling? No. We do not believe entry and exit screenings would work to reduce the spread of this disease. However country-level measures to respond to a public health risk are the decision of national authorities, under the International Health Regulations 2005. Countries that adopt measures that significantly interfere with international traffic (e.g. delaying an airplane passenger for more than 24 hours, or refusing country entry or departure to a traveller) must provide WHO with the public health reasoning and evidence for their actions. WHO will follow up with all of its Member countries on such matters. Travellers should always be treated with dignity and respect for their human rights. How can I protect myself from influenza A(H1N1) when I am travelling? People who are ill should delay travel plans. Returning travellers who become ill should contact their health care provider. Travellers can protect themselves and others by following simple prevention practices that apply while travelling and in daily life. The safety of pork Is it safe to eat pork and pork products? Yes. influenza A(H1N1) 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 influenza A(H1N1) virus is killed by cooking temperatures of 160°F/70°C, corresponding to the general guidance for the preparation of pork and other meat. What can I do? What can I do to protect myself from catching influenza A(H1N1)? The main route of transmission of the new influenza A(H1N1) virus seems to be similar to seasonal influenza, via droplets that are expelled by speaking, sneezing or coughing. You can prevent getting infected by avoiding close contact with people who show influenza-like symptoms (trying to maintain a distance of about 1 metre if possible) and taking the following measures:

• avoid touching your mouth and nose
• clean hands thoroughly with soap and water, or cleanse them with an alcohol-based hand rub on a regular basis (especially if touching the mouth and nose, or surfaces that are potentially contaminated)
• avoid close contact with people who might be ill
• reduce the time spent in crowded settings if possible
• improve airflow in your living space by opening windows
• practise good health habits including adequate sleep, eating nutritious food, and keeping physically active.

What about using a mask? What does WHO recommend? If you are not sick you do not have to wear a mask. If you are caring for a sick person, you can wear a mask when you are in close contact with the ill person and dispose of it immediately after contact, and cleanse your hands thoroughly afterwards. When and how to use a mask? If you are sick and must travel or be around others, cover your mouth and nose. Using a mask correctly in all situations is essential. Incorrect use actually increases the chance of spreading infection. How do I know if I have influenza A(H1N1)? You will not be able to tell the difference between seasonal flu and influenza A(H1N1) without medical help. Typical symptoms to watch for are similar to seasonal viruses and include fever, cough, headache, body aches, sore throat and runny nose. Only your medical practitioner and local health authority can confirm a case of influenza A(H1N1). 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 nose and mouth when coughing and sneezing and, if using tissues, make sure you dispose of them carefully. Clean your hands immediately after with soap and water or cleanse them with an alcohol-based hand rub
• if you do not have a tissue close by when you cough or sneeze, cover your mouth as much as possible with the crook of your elbow
• use a mask to help you contain the spread of droplets when you are around others, but be sure to do so correctly
• inform family and friends about your illness and try to avoid contact with other people
• If possible, contact a health professional before traveling to a health facility to discuss whether a medical examination is necessary.

What should I do if I need medical attention?

• If possible, contact your health care provider before traveling to a health facility, and report your symptoms. Explain why you think you have influenza A (H1N1) (e.g. if you have recently traveled to a country where there is an outbreak in people). Follow the advice given to you.
• If you cannot contact your health care provider before traveling to a health facility, tell a health care worker of your suspicion of infection immediately after arrival at the clinic or hospital.
• Cover your nose and mouth during travel.

Should I go to work if I have the flu but am feeling OK? No. Whether you have influenza A(H1N1) or a seasonal influenza, you should stay home and away from work through the duration of your symptoms. This is a precaution that can protect your work colleagues and others. Can I travel? If you are feeling unwell or have symptoms of influenza, you should not travel. If you have any doubts about your health, you should check with your health care provider. Are some people more at risk? More study is needed to determine if some populations (i.e. younger or older people, or people with other medical conditions) could be affected by the outbreak, of if they are at higher risk for severe illness. WHO recommends that everyone take precautions to prevent the spread of infection. Are there any special recommendations for pregnant women? Yes, they are vulnerable. Like everyone, they should take all the necessary precautions.