Public Health Surveillance
The MOPECE (Módulos de Principios de Epidemiología para el Control de Enfermedades) training modules, now in their second edition (2001), continue to be a training instrument in basic epidemiology for local health professionals and teams to promote the use of epidemiology in the management of health services and the implementation of practical responses to the daily health problems in the population.
The objectives of MOPECE are to:
The MOPECE training modules are comprised of 6 units that cover topics such as health and diseases in the population, measuring health conditions and diseases, surveillance in public health, field epidemiology and research, and control of diseases in the population.
The second edition of the MOPECE modules are available in Spanish, Portuguese, and French.
For further information about MOPECE and training workshops, please contact: email@example.com
Every year the Governments of the countries of the Americas, acting through their representatives in the meetings of the Governing Bodies of the Pan American Health Organization, confer the PAHO Award for Administration in recognition of an outstanding contribution in the field of administration within the framework of national health services.
The H1N1 pandemic was characterized by the emergence of a new influenza virus to which many people had no pre-existing immunity. It caused unusual and extensive outbreaks of disease in the summer months in many countries and very high levels of disease in winter months. It was also characterized by an almost complete dominance of the pandemic virus over other seasonal influenza viruses, and by unusual clinical patterns where the most severe cases were occurring most often in younger age groups.
We are now moving into a situation where many people in all age groups in many countries have some immunity to the new virus, and where no unusual summer outbreaks have occurred in either the Northern or Southern Hemispheres, and where seasonal influenza A (H3N2) and influenza B viruses are being reported in many countries. Based on these criteria we see an overall picture where pandemic patterns have been replaced by seasonal patterns of influenza. However, it is important to realize that individual influenza seasons themselves can be highly variable. In some years, the impact can be mild while in other years it can be quite severe.
In the post pandemic period, cases and outbreaks due to the H1N1 virus will continue to occur. In addition, it is most likely that younger age groups, including pregnant women, will continue to be affected disproportionately by cases of severe disease from H1N1, including viral pneumonia. It is impossible to predict if younger people will remain at higher risk or whether this will change over time. Given this picture, it will remain important for people to take prudent steps to protect themselves from influenza infection such as through use of vaccines, hand and respiratory hygiene and other steps.
The future impact of the H1N1 virus is not possible to predict. On the one hand, the H1N1 virus is expected to continue to circulate as a seasonal influenza strain for the foreseeable future and because of this, more people will develop immunity to this current version of the virus. On the other hand, the virus is also expected to change over time as a result of antigenic drift and these changes may mean that the immunity that has developed to this version of the virus may become less protective against future versions. In addition, there may well be areas of some countries that were less severely affected in earlier periods of transmission that could experience more severe disease in a second season.
WHO has been monitoring epidemiological and virological evidence from all parts of the world, including both Northern and Southern Hemispheres, to determine when the pandemic is over. In particular, WHO has waited until the picture in the Southern Hemisphere and tropical countries has become clearer.
4. What does the end of the pandemic mean for individuals?
For most individuals, there will not be much impact on their daily lives. Regardless of whether the world is in a pandemic situation or not, many individuals are always susceptible to severe infection by influenza viruses. Therefore, individuals should take prudent steps to reduce their risk of infection, including use of influenza vaccine when available and especially if they are in group at high risk for severe illness. Most individuals who become ill can be treated safely at home but caretakers and family members should be aware that if an individual develops symptoms suggesting more severe disease, such as prolonged high fever, trouble breathing, or confusion, then professional medical care should be sought.
Based on available evidence, the virus currently continues to pose a higher risk for severe illness in some groups, including young children, pregnant women and those with respiratory or chronic health conditions. This will likely continue to be the case as these same groups were known to be at higher risk of severe disease with the previously circulating seasonal influenza strains
Individuals can continue to protect themselves from the virus through preventive measures such as practicing good respiratory etiquette including covering sneezes and coughs. WHO also continues to recommend vaccination against the virus through a monovalent (single virus) pandemic vaccine, or a trivalent (three viruses) seasonal influenza vaccine, depending on whichever is available locally. Additional measures such as respiratory etiquette (for example, covering your mouth when you cough) and good hand hygiene practices also have roles in preventing spread and acquisition of infection.
Even as we move out of the pandemic period, it is important for countries to remain vigilant and alert for infections and outbreaks and to continue to take steps to protect their populations against influenza.
WHO recommends that countries:
The H1N1 pandemic provided a significant challenge to all countries and WHO encourages countries to assess their experience and identify lessons that can be applied to strengthen their preparedness and response to future pandemics.
8. What is the possibility of this virus drifting or mutating into a more virulent form?
Flu viruses are predictable in the fact that they all change over time, but are unpredictable as to the direction in which they will change. As the human population develops immunity to this version of this virus, it is anticipated this virus will change to evade the immunity through a process of mutations known as antigenic drift. What we do not know is what the changes may be. It is possible for the virus to become milder, or possibly, more pathogenic and severe. It may develop new properties such as antiviral drug resistance. This is one of the reasons why global monitoring is used to follow changes in influenza viruses and why influenza vaccines must be updated each year. .
1. Did pandemic preparedness waste resources since many vaccines and antivirals were not used and have to be destroyed?
Countries and WHO undertook broad efforts to be better prepared for the pandemic because being unprepared is always less desirable. The overall effort to better prepared for this pandemic had enormous benefits that will continue into the future and that will broadly help countries to be better prepared for other disease threats. For example, because of the passage of the International Health Regulations, one of the critical preparations, countries now report disease threats and important information quicker than ever. This will strengthen the world's alertness and responsiveness. Within this broad context, vaccines and antivirals can be seen to be one part of a larger overall effort to be better prepared. Although minimizing waste is important. their availability helped to mitigate the health impact of the pandemic .
Over the course of the pandemic, increasing clinical data have been published in peer-reviewed medical journals confirming that prompt use of antivirals correlates with improved recovery from illness and fewer deaths. Evidence shows that antivirals have been especially effective for treating patients at increased risk of developing complications from H1N1. Similarly, the H1N1 vaccine has been demonstrated through world wide monitoring efforts to be safe and in studies to be effective. Now the pandemic H1N1 virus has been incorporated into the seasonal vaccines. Finally, it must be stressed that in a future pandemic, we could face a situation where not enough vaccines and antiviral drugs will be available. The big issue is not remaining stocks, but how to make sure that the world's populations can have enough vaccines and antiviral drugs when needed. That is still an unmet challenge.
The H1N1 (2009) pandemic was a real pandemic. Laboratory analyses showed that this influenza virus was genetically and antigenically very different from other influenza viruses circulating among people. Epidemiological information demonstrated global epidemiological patterns -- such as large summertime outbreaks -- that are not normally seen with seasonal influenza but are consistent pandemic influenza. Over a two-month period, from the end of April to the end of June, this virus was documented to have spread to about 120 countries. Finally, this virus also caused severe disease and death occurred more often in younger people than older people -- which is another unusual disease patterns.
As the pandemic evolved, clinicians frequently identified cases of primary viral pneumonia related to pandemic influenza, which was rapidly progressive and frequently fatal, This is not reported very often with seasonal influenza.
3. Was WHO's credibility affected by the declaration of the pandemic?
When WHO Director-General Dr. Margaret Chan announced the pandemic on 11 June 2009, she indicated in her speech that WHO had reason to believe that the pandemic would be of "moderate severity."
The moderate assessment, at that time, reflected the fact that most people recovered from infection without the need for hospitalization or medical care and that in general, health care systems in most countries were able to cope. Nonetheless, it was also noted that severe cases were occurring in significant number among younger people and that in some countries, the intensive care units dealing with critically ill patients were under pressure in some hospitals. It was quite a challenge to provide a global assessment for a disease whose impact could be quite variable in different locations and populations. Finally, WHO also was very aware that the severity of pandemics could change over time.
5. Did WHO ever communicate that a pandemic might cause ''enormous numbers of deaths and illnesses''?
There has been some confusion about this issue. In the past, WHO has pointed out that a pandemic could cause large numbers of deaths because this has been seen in previous pandemics. However, it is not true that WHO claimed this pandemic would be severe. Moreover, a requirement for a certain level of severity was not ever part of the definition of a pandemic.
In early 2003, WHO posted a description of one pandemic scenario that could cause "enormous numbers of deaths and illnesses" on its web site. The online document was written when the concern about the next influenza pandemic focused on H5N1 avian influenza, a virus shown to have highly lethal effects. This online document was revised in May 2009 to avoid confusion.
In order to prepare as effectively as possible, all planners must have some idea of what they might encounter. In this regard, preparing for influenza pandemics is notoriously difficult because history has shown us that the range of possible deaths is very wide as was seen from previous pandemics ranging from severe, such as that of 1918, to milder, such as that of 1957 and 1968. Governments and organizations tried to use this historical information to be as prepared as possible for all potential scenarios.
2. How many people died in this pandemic? When will you know the estimated total deaths? What proportion of the populations in countries has been infected by the pandemic flu virus?
This is not yet known. The currently reported count of over 18,000 deaths from pandemic H1N1 represents a minimum number because these numbers reflect only deaths in which pandemic infection was individually confirmed by laboratory testing. This approach provides a significant underestimate of true deaths.
Work is in progress to assess the full public health impact of the pandemic and many countries have ongoing studies under way to determine how many people have been affected by the pandemic.
Pandemic response: antivirals and vaccine
Antiviral drugs and vaccines are the only measure available that can provide direct and specific protection against influenza viruses. The H1N1 pandemic influenza virus was shown to be sensitive to one group of antiviral drugs (oseltamivir and zanamivir) and resistant to another group of antiviral drugs (amantadine and rimantadine).
WHO provided a range of recommendation for interventions against pandemic influenza including steps that required no drugs or vaccines, to guidance on the use of available drugs and vaccines. In terms of antiviral drugs, reducing severe illness from pandemic H1N1 in high risk groups such as pregnant women and children is a WHO priority. Evidence clearly shows that early treatment with antivirals has been especially effective for treating patients at increased risk of developing complications from H1N1*.
As of 28 July 2010, 302 cases of oseltamivir resistance have globally been reported to WHO.
3. Does WHO still recommend oseltamivir use now that the pandemic is over?
WHO's guidelines for use of antiviral medicines, which refer to both seasonal and pandemic influenza, should continue to be followed. Although we are now post-pandemic, the H1N1 virus is still circulating as one of the seasonal flu strains. It is likely that we will still see severe illness in higher risk individuals as well as otherwise healthy persons. Early recognition and appropriate treatment remains important.
The total emergency stock delivered by WHO to all locations during this pandemic was about 3 million treatment courses of oseltamivir, which includes 2,220,416 courses of oseltamivir sent to 71 developing countries as the pandemic first developed and an additional 200,024 courses provided to Mexico.
5. Will WHO continue to consider that oseltamivir as an essential medicine?
WHO added oseltamivir to the Model List Of Essential Medicines in January 2010 for treatment of pandemic H1N1 in patients with severe disease, or in high-risk groups for severe disease on the basis of an emergency session of the WHO Expert Committee on the Selection and Use of Essential Medicines reviewed the scientific evidence. The committee drew particular attention to the potential benefit in very young children and pregnant women. The Expert Committee recommended that its decision to include oseltamivir should be reviewed at their meeting in March 2011.
When it is available, WHO strongly recommends the use of influenza vaccine to protect people as a safe and effective countermeasure to severe illness. This H1N1 influenza virus is expected to continue to circulate worldwide for many years, and many people are still susceptible to infection. WHO recommends in particular that health care workers and high-risk groups to be vaccinated.
2. How many people have been vaccinated worldwide?
Between September 2009 and June 2010, more than 350 million doses of vaccine were administered, targeting various populations.
3. How safe are the pandemic vaccines? Has WHO received any reports regarding adverse events due to H1N1 pandemic vaccine use? If so what were they and how were they handled?
The Global Advisory Committee on Vaccine Safety, which met on 16–17 June 2010, concluded that the safety profile of the pandemic A (H1N1) 2009 influenza vaccines is reassuring.
The committee also concluded that most of the adverse events that have been reported
4. Does pandemic H1N1 vaccine protect individuals against seasonal flu?
The pandemic H1N1 2009 virus is expected to continue to circulate as one of the seasonal flu strains for some time to come. The current seasonal trivalent vaccine includes the pandemic H1N1 strain, as well as other seasonal strains (H3, B), and will protect against all the expected seasonal influenza viruses. The monovalent (single virus) pandemic vaccine will only protect against the H1N1 virus.
Pandemic H1N1 virus caused most of its severe or fatal disease in younger people, both those with chronic conditions as well as healthy persons, and caused many more cases of viral pneumonia than is normally seen with seasonal influenza.
Since no one can accurately predict which or how many of the circulating influenza viruses will infect them, the trivalent seasonal influenza vaccine will provide the broadest protection. However, in places the trivalent vaccine is not available, it is still prudent to be vaccinated against the H1N1 virus to prevent severe illness.
5. What should countries do with any remaining stocks of pandemic H1N1 vaccines?
The pandemic H1N1 virus has become firmly established world wide and is still in circulation along with seasonal H3 and B viruses. WHO continues to recommend the use of vaccine (within the valid shelf-life) for health workers and high risk groups.
Calling and end to the pandemic means that the global situation for influenza is returning to a more normal seasonal picture. However, it does not mean that the H1N1 virus has disappeared. This virus is still circulating in all parts of the world and is expected to continue circulating in the future and to cause disease. WHO continues to recommend use of vaccine to protect against this virus and other circulating influenza viruses, and will continue to try and make vaccine available to countries that have no, or limited, access to vaccines and have requested the assistance.
2. How many doses of H1N1 pandemic vaccine have been delivered, and to how many countries?
3. How many doses of H1N1 pandemic vaccine are still to be delivered, and by when?
Delivery of more than 15.2 million doses are in progress to another 18 countries.
4. Why did it take so long for WHO to deliver the vaccines to countries?
Delivering pandemic influenza vaccine under urgent conditions was one of the most difficult activities conducted by countries and WHO. Donor countries and companies and recipient countries and WHO had to ensure that logistics planning, regulatory approvals and all systems were in place to donate, receive, regulate and distribute the vaccines to the priority groups. Recipient countries were also required to develop approved plans to ensure distribution of the vaccines and to finance the immunization activities. The process was complex and varied by country.
5. Is sending the vaccine to the developing world when the pandemic is over, a way of getting rid of excess vaccine?
No. It is a way of maximizing protection against a virus that still infects and causes disease. Improved access to pandemic vaccines was, and still is, one of the first requests of low and middle income countries towards better equity during public health emergencies of international concern. WHO is only delivering vaccine to countries who have confirmed that they want the product to immunize their population and are prepared and able to use it.
International Health Regulations (2005)
The IHR were enacted as a foundation to enable the world to deal with a wide range of international health threats. It is important to recall that the IHR are implemented daily, around the world for many disease situations. One of the key features is the designation by every WHO Member State of a National Focal Point who facilitates key communications with WHO. This enables WHO to provide critical information to the other countries. Notifications and other reports involving these focal points are a very important source of event-related information on serious international public health events caused by the wide range of biological, chemical and radio-nuclear public health risks covered by the IHR - including pandemic influenza. In relationship to the H1N1 pandemic, this was the single largest and most complex situation in which the IHR (2005) were used thus far and it is clear that the legal and practical framework provided by the IHR (2005) was one of the key reasons why communications and actions were taken more quickly and more effectively compared to past disease situations.
All countries retain the right and authority to take actions within their borders that they deem necessary to protect human health. The WHO IHR "temporary recommendations" provide "nonbinding advice" to countries. The IHR also provide that countries can implement measures that vary from such recommendations if certain established scientific and other requirements are fulfilled. In this regard, it is important to note that many countries did comply with the IHR temporary recommendations provided by WHO with regard to international travel and trade, and that pandemic-based restrictions on international movement were often revised or removed as experience progressed. Finally, it is important to recall that there were other temporary recommendations (concerning e.g. surveillance) that were very important and that, to our knowledge, were largely complied with.
3. What does the end of Public Health Emergency of International Concern (PHEIC) mean? Why did WHO have to wait to declare the end of PHEIC at the same time as post-pandemic?
Declaration of a Public Health Emergency of International Concern under the International Health Regulations means there is formal determination that an extraordinary event is underway, which constitutes a public health risk to other countries through the international spread of disease and that potentially requires a coordinated international response.
With the pandemic H1N1 influenza virus transitioning to a seasonal pattern, the public health response is also transitioning from an emergency approach back to a more sustainable long term response appropriate for the situation. This includes ongoing close monitoring for any change in the virus and any unusual public health event that could arise.
Even with the ending of the PHEIC, countries will still be under obligations to notify or report events. In addition, countries will still have obligations concerning their core public health capacities for surveillance and response, which may involve surveillance for influenza. WHO will also still have its mandate to conduct global public health surveillance, to seek verification as necessary, to assist and collaborate with Member States, and to issue recommendations and advice on influenza - as it does in many other disease situations. Indeed, the large majority of IHR provisions will still apply - excepting those which require a declaration of a PHEIC as a pre-requisite.
The Emergency Committee for pandemic H1N1 is comprised of international experts from a variety of disciplines relevant to this public health emergency of international concern. Experts are selected in accordance with Article 47 of the IHR. There were 15 Members and 1 expert advisor to the Committee.
NOTE: the list of names, affiliations and summaries of any relevant interests of the Emergency Committee members (and their adviser) will be posted on the WHO web site on the same day as the announcement of termination of the PHEIC.
Note that at any one time during the existence of the Emergency Committee, there were generally 14 Members and 1 expert, as 1 expert was suspended from the Committee when he took a position with WHO and another was added to the Committee at approximately that time period.
This EC was the 1st such Committee convened under the IHR. The experience of SARS and many other health events has demonstrated the decisions taken during such emergencies can cause considerable economic and social disruption. Therefore, it was evident that members of the EC could be subject to considerable political, commercial or media pressures which might compromise or be perceived as compromising the objectivity of their advice
Both lists of names are made public, but at different times because the remits of the two types of IHR committees are very different. The role of the EC is to provide advice in the context of urgent events and during an ongoing global public health emergency. Its guidance can directly affect events and decision.
In contrast, the Review Committee's work is to review what has occurred and to provide longer term guidance on what should be learned and done in the future. Its work is conducted in accordance with the IHR through a process in which States Parties to the IHR, many international organizations and non-governmental organizations are invited to submit information and attend the plenary sessions of the Review Committee. This is not the case for the EC, whose structure and functions are quite different.
In January 2010, the WHO Executive Board requested a proposal from the Director-General on how to assess the international response to the pandemic influenza, and to use an IHR Review process that was already scheduled to review the functioning of the IHR to also review the global response to the pandemic..
The H1N1 pandemic is the first public health emergency of international concern to occur under the IHR, and so review of the IHR and of the global handling of the pandemic influenza are closely related.
2. What are the objectives of the Review Committee?
The review has three key objectives:
3. How are countries and organizations participating in the review process?
The Review Committee has received submissions from individuals and from organizations, including those highly critical of WHO in the context of the pandemic, on key issues, concerns and lessons learnt related to the pandemic response and functioning of the IHR. Countries can and have made statements at plenary sessions of the Review Committee.
4. Who are the Review Committee members?
Professor Harvey V. Fineberg of the (U.S.) National Institute of Medicine is the chairman of the Review Committee and Prof Babatunde, former Minister of Health of Nigeria, is its Vice-Chairman. The Committee consists of 27 members. The members were selected from the IHR Roster of Experts and were selected in accordance with IHR requirements. The committee as a whole represents a broad mix of relevant expertise and practical public health experience from developed and developing countries. The members of the RC are not WHO staff, nor do they receive funding from WHO for their contributions to the review process. The names of the members are posted on the WHO web site.
The committee will present its findings to the WHO Director-General, who will report them to the World Health Assembly (WHA) in May 2011. The 128th session of the Executive Board will be informed of progress made by the RC.
No. The decision to declare a pandemic was based on the predetermined/defined epidemiological and virological criteria. WHO's decision in declaring the H1N1 pandemic was never influenced by private or commercial interests. Once a decision was made to declare a pandemic and to develop pandemic vaccines, WHO worked with industry and other partners to ensure that the public and private sectors worked together appropriately. Allegations that WHO declared a pandemic to bring economic benefit to industry are unfounded.
All experts are required to declare their professional and financial interests which may or may be perceived as affecting the objectivity and impartiality of their advice when they participate in WHO advisory groups. These declared interests are analysed by WHO to guard against potential conflicts or the perception of them. If there is an issue, WHO follows it up.
WHO is well aware that some scientific experts have contact with industry: Given this reality, the system just described is aimed at protecting the Organization against the possibility that such contacts will create potential conflicts of interest when advice is provided to WHO.
While concerns about minimizing the risk of undue influence by industry are important, WHO is also concerned that it continues to have access to the best possible global knowledge, experience and expertise when facing complex public health challenges . A balance is possible because all contacts with industry are not the same and such contacts do not automatically create conflicts of interest. Each situation must be examined individually.
WHO publishes summaries of relevant interests , following meetings of advisory bodies. The Organization acknowledges there has been some inconsistency in the past decade in the practice of publishing relevant interest summaries, which would not be acceptable practice by today's standards and WHO is committed to improving in this area. It should also be acknowledged that internationally accepted standards and best practices for managing potential conflicts of interests have evolved considerably during the last 10-15 years.
All experts involved in the development of the WHO Guidelines on the Use of Vaccines and Antivirals during Influenza Pandemics 2004 were required to submit a declaration of interest form which were then closely reviewed. However, WHO acknowledges that a summary of relevant interests was not included in the final publication. WHO recognizes this oversight and over the course of the past six years, a number of policies and practices have been developed to ensure that this situations does not repeat itself.
WHO is always seeking to improve its measures to ensure adequate transparency and procedures have evolved a great deal over the past few years, as they have in other sectors. The Director-General is personally committed to ensure that the Organization will continue to review its processes and rules for disclosure to see how further improvements can be made.
5. Did WHO make any agreements with pharmaceutical companies before or during the pandemic?
WHO concluded agreements with some companies after the declaration of the pandemic related to donations of vaccines, antiviral drugs and ancillary materials and funds to support vaccine and antiviral treatment for distribution to resource challenged countries.
WHO did not buy vaccines from the private sector. WHO did not intercede in or influence any negotiations between pharmaceutical companies and countries or other public entities for the purchase of vaccines.
Many countries and their public health agencies as well as WHO are reviewing what should be learnt from the event of the past 18 months. In addition, WHO has also asked an IHR Review Committee to review the international pandemic response, including WHO's performance, and to report their finding to the World Health Assembly (WHA).
The assessment of the global response to the pandemic H1N1 is being conducted by the International Health Regulations Review Committee, a committee of experts with a broad mix of scientific expertise and practical experience in public health. It is too early to comment on the outcomes of this review.
WHO faced difficult communications challenges that it had never dealt with before. The challenges were difficult in part because the pandemic event was so prolonged and complicated and in part because the nature of communications is changing. For example, online social media gave everyone, including the media and the public multiple unfiltered voices. WHO and countries will need to better adapt and work in this new environment.
3. Is WHO going to review the pandemic phases? Do you think severity should be included in the criteria for announcing phase 6?
Facilitating the planning and response of countries to pandemics remains critical, as does finding ways to effectively assess and communicate the severity of events such as pandemics. WHO will focus on these issues but deliberations of the IHR Review Committee findings, which will be presented at the WHA next May, will be important for deciding how to proceed.
- Actualizacion Regional Dengue en las Americas (Publicada el 14 de Octubre de 2009) 2009-10-15 19:48:30