Media Briefing: Influenza A (H1N1)
(Conducted by Dr. Jon K. Andrus, Pan American Health Organization, May 5, 2009)
Good afternoon. Welcome again to all members of the Press who are on the line, and thank you again for taking the time to listen to today's briefing by the Pan American Health Organization on the Influenza A(H1N1) epidemic.
- Let's start by summarizing the epidemiologic situation:
- Globally, the latest data show 21 countries officially reporting >1,300 confirmed cases of Influenza A(H1N1) infection.
- There have been 30 deaths among confirmed Influenza A(H1N1) cases (29 in Mexico and 1 in the USA).
- In our Region of the Americas, we now have 1,255 cases (Canada 140, Colombia 1, Costa Rica 4, El Salvador 2, Mexico 822, and USA 286 cases).
- Again, the numbers will rise and drop. We know as of today that Mexico has more than 11,000 suspected cases under investigation. We need to stay focused on what we need to do control this outbreak, those activities related to preparation and prevention.
- Yesterday, I emphasized that the following points are important for all individuals to understand to protect themselves and their families. I want to repeat those points. I happen to teach masters of public health students down the street at George Washington University, and I find a little repetition is good and often appreciated by everyone. Those points are the following:
- All flu outbreaks are serious. This one is especially serious because it is a new virus. This means that people have not been previously exposed to this virus will therefore have no immunity.
- The incubation period of this disease is probably a couple of days with a range of 2-5 days or so based on seasonal influenza and preliminary data coming from the outbreak.
- The period of communicability is from 1 day prior to symptoms onset to 5 days afterwards.
- The method of transmission is by droplets, so hand washing, personal hygiene, covering the mouth when coughing, and social distancing cannot be over-emphasized.
- The clinical features remain unchanged; the infections are mild to moderate.
- The Southern Hemisphere is about to enter its winter season, and the winter season provides better conditions for more rapid influenza virus spread.
- So let's review some of the burning issues for today. First, we have received hundreds of questions about the phases of this pandemic and how that relates to the severity of the disease. Let me start by saying there is no connection. The phases refer to the geographic spread of the disease, not the severity of the disease.
- Let's review briefly the definitions of the phases. For purposes of this discussion, I am going to lump phases 1 to 3 together because they are behind us and just say that what we were really dealing with during these phases was predominantly animal infections and very few human infections. Moving to phase 4 requires documentation of sustained human-to-human disease spread. Phase 5 would be sustained human-to-human spread in a community of two or more countries in one region of the world. Phase 6 meets the phase 5 criteria with the addition of sustained human-to-human disease spread in a community in at least one other country in another WHO region of the world. Subsequently, WHO uses 2 additional definitions post-peak, and post-pandemic phases. Post-peak is when transmission is clearly diminishing; however, I should say that there is always a possibility of recurrent events. The other definition is post-pandemic phase, when disease activity has diminished to the levels seen during the regular influenza seasons.
- Phase 6 is a declaration of a global pandemic; again, not an indication of disease severity. While phase 5 requires countries to activate their emergency plans, phase 6 requires countries to implement them. In our Region, most countries are already implementing their emergency plans before the official announcement that we are in phase 6. And, indeed, this is good, because we are in the heart of the storm. The term phase 6 is more relevant for the rest of the world than it is for us because we are already implementing our emergency plans.
- For us here in the Americas, we are not certain how the risk assessment of A(H1N1) virus will evolve, but we do know that its management will likely be a long-term challenge, whether we move to phase 6 or not.
- Another issue that we are dealing with is how to interpret, and either confirm or dispel, reports that we receive so that we will know that we are sharing the most accurate information possible with you, the press, and the public. Since this crisis began, we have been getting dozens of reports each day from various sources, including the press. For many of these reports, we need to follow-up and investigate them. You can imagine how much time and effort this takes. But when necessary, it has to be done.
- Since we have said that there should be no travel restrictions or closure of borders, we would like to also emphasize that countries around the world should be fair with individuals. It is not helpful to blame or stigmatize people who happen to be citizens of affected countries or happen to become victims of disease.
- Dr. Mirta Roses, the Director of the Pan American Health Organization, has asked me to walk you through what would the scenario on what happens to a sick individual that seeks care in our countries' primary health care systems.
- Fortunately, we have the health infrastructure in place in most communities for individuals to seek care in the nearest health center or hospital. We know that in Mexico, in communities that have less developed levels of care, mobile teams have been organized to look for cases, obtain blood specimens when appropriate, and treat the patient with antivirals if indicated. These mobile teams have been organized by the Ministry of Health in Mexico to cover large geographic areas each day.
- In communities where health centers are more accessible, a provider screens the patient and determines whether the presentation of the patient's signs and symptoms warrant a blood test for Influenza A. Appropriate treatment is provided at that point of patient contact as well. Depending upon the hospital's or clinic's capacity, the blood specimen is tested there or sent to a more centralized reference laboratory for determining if the patient is infected with Influenza A. If so, the patient is classified as a probable case using the standard case definitions. The specimen that tested positive for Influenza A is then sent to an even more specialized lab to determine if the Influenza A positive test is indeed positive for Influenza A(H1N1). In that situation, the case is confirmed as a positive case with disease caused by this new Influenza A(N1H1) virus.
- The investigation leading to a probable and then confirmed case designation for a particular patient is also a signal for implementation of a cascade of other public health activities. The patient's history is important to determine in order to understand where and when the patient most likely acquired the infection. This also helps us to determine what people were exposed to the virus. Contacts of the case are investigated. This is called in public health circles the contact investigation. Early in the outbreak these contact investigations are critical in order to prevent spread of the disease. Once the outbreak has become more widespread, it becomes more difficult to investigate the hundreds, thousands, and then millions of potential contacts.
- These investigations require a sophisticated laboratory network, a large and extensive team of field staff to conduct the investigations and collect the specimens, public health experts, epidemiologists, and virologists working in the labs.
- Contacts that test positive require follow-up. This means going back to the community and trying to find and notify the contact of his or her test results and also provide the necessary treatment, if appropriate. Aside from the rather extensive network of human resources, this work requires an enormous volume of reagents and laboratory supplies. I hope you can begin to imagine the huge volume of effort that all this work entails.
- In addition, for the specimens found to be positive for A(H1N1), to the extent possible, the virus is studied in more detail. For example, the genetic sequence is determined to see if over time there are mutations occurring, and if they are occurring, to what extent and where they are occurring on the genome, and also at what rate. So, this is a highly sophisticated process that the CDC, in collaboration with PAHO, is undertaking to help the Mexican authorities.
- This also explains why the mobilization of experts from PAHO's Regional and country offices, and from its partners in Public Health Canada and the U.S. Health and Human Services' CDC to the outbreak was absolutely critical.
- I would like to end by again reminding people that with the Southern Hemisphere entering its winter flu season, there is a strong likelihood that there will be an upsurge of cases in your countries. Implementing your pandemic plans is very important. Most countries are already protecting their populations with seasonal vaccination as we speak. In addition, most, if not all, of our Southern Hemisphere countries have already enhanced their surveillance and monitoring procedures. The challenge will be not to drop your guard.
- We have never had such close surveillance of the emergence of a new virus such as for this new Influenza A(H1N1) virus, and so we are learning as we go.
- And, finally to say again that the top priority for PAHO is ensuring fair and equitable distribution of resources, such as antivirals and vaccines.
- Let me stop there to address any questions that you may have. Thank you.
(You can watch this media briefing on PAHO's Webcasts Page)