WHO raises pandemic alert to Phase 5 - "strong signal that a pandemic is imminent" (4/30)
“The situation continues to evolve rapidly,” according to a WHO press release. “As of 18:00 GMT, 29 April 2009, nine countries have officially reported 148 cases of swine influenza A/H1N1 infection. The United States government has reported 91 laboratory confirmed human cases, with one death. Mexico has reported 26 confirmed human cases of infection including seven deaths.
“The following countries have reported laboratory confirmed cases with no deaths - Austria (1), Canada (13), Germany (3), Israel (2), New Zealand (3), Spain (4) and the United Kingdom (5).”
Dr. Chan stated: “All countries should immediately activate their pandemic preparedness plans. Countries should remain on high alert for unusual outbreaks of influenza-like illness and severe pneumonia.
“At this stage, effective and essential measures include heightened surveillance, early detection and treatment of cases, and infection control in all health facilities.
“This change to a higher phase of alert is a signal to governments, to ministries of health and other ministries, to the pharmaceutical industry and the business community that certain actions should now be undertaken with increased urgency, and at an accelerated pace.”
In the 2009 revision of the pandemic phase descriptions, WHO retained the use of a six-phased approach for easy incorporation of new recommendations and approaches into existing national preparedness and response plans. Phases 1–3 correlate with preparedness, including capacity development and response planning activities, while Phases 4–6 clearly signal the need for response and mitigation efforts. Periods after the first pandemic wave are elaborated to facilitate post pandemic recovery activities.
Phase 5 is characterized by human-to-human spread of the virus into at least two countries in one WHO region. While most countries will not be affected at this stage, the declaration of Phase 5 is a strong signal that a pandemic is imminent and that the time to finalize the organization, communication, and implementation of the planned mitigation measures is short.
Phase 6, the pandemic phase, is characterized by community level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5. Designation of this phase will indicate that a global pandemic is under way.
Said Dr. Chan: “Influenza pandemics must be taken seriously precisely because of their capacity to spread rapidly to every country in the world. On the positive side, the world is better prepared for an influenza pandemic than at any time in history. Preparedness measures undertaken because of the threat from H5N1 avian influenza were an investment, and we are now benefitting from this investment.
“Let me remind you. New diseases are, by definition, poorly understood. Influenza viruses are notorious for their rapid mutation and unpredictable behaviour. WHO and health authorities in affected countries will not have all the answers immediately, but we will get them.
“The biggest question, right now, is this: how severe will the pandemic be, especially now at the start? It is possible that the full clinical spectrum of this disease goes from mild illness to severe disease. We need to continue to monitor the evolution of the situation to get the specific information and data we need to answer this question.
“From past experience, we also know that influenza may cause mild disease in affluent countries, but more severe disease, with higher mortality, in developing countries. No matter what the situation is, the international community should treat this as a window of opportunity to ramp up preparedness and response,” said Dr. Chan.
According to a WHO press release, at this time “WHO advises no restriction of regular travel or closure of borders. It is considered prudent for people who are ill to delay international travel and for people developing symptoms following international travel to seek medical attention, in line with guidance from national authorities.
“There is also no risk of infection from this virus from consumption of well-cooked pork and pork products. Individuals are advised to wash hands thoroughly with soap and water on a regular basis and should seek medical attention if they develop any symptoms of influenza-like illness.
The follow Q&A is posted on the WHO web site:
What is swine influenza? 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.
How do people become infected? 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.
Is there a human vaccine to protect against swine influenza? 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.
What medicines are available for treatment? 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 patient. 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.
How can I protect myself from getting swine influenza from infected people? 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.
What should I do if I think I have swine influenza? If you feel unwell, have high fever, cough and/or sore throat:
- Stay at home and keep away from work, school or crowds as much as possible.
- 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 frequently and thoroughly, especially after coughing or sneezing.
- Inform family and friends about your illness and seek help for household chores that require contact with other people such as shopping.
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.