Adapted from "Pandemic influenza preparedness and response: a WHO guidance document ". Other influenza viruses mostly H1N1 types have emerged in the 20th Century.
They have not caused pandemics but they have required inclusion in the seasonal vaccines. In one H1N1 virus emerged, again from China and spread world wide mostly affecting children and adolescents. This is impossible to predict. Certainly a higher proportion of the population become infected with the new influenza virus than with seasonal influenza. A proportion of the people infected with the virus become very ill, and some of them die. A pandemic can come in a single wave or as two or wave separated by few months or a year.
Sometimes the second wave is more severe than the first. Each wave can last up to four or five months rising and then falling in intensity like seasonal influenza in the winter. These waves do not happen at exactly the same time or to the same extent in every part of a country. In Europe there is often a tendency for the waves to progress from West to East, but often starting in a pandemic with the countries that have the most contact with the countries first affected in another part of the world.
One earlier planning estimate of the additional stress that a European health service caring for people might experience over the first wave of a pandemic is as follows:. These data can be scaled up for larger populations so for a Million Population multiply by ten. However, perhaps the same proportion might be off because they were caring for someone else who is in the family. This is only one estimate undertaken for planning and there are others estimates that can be made which will look worse or better.
That is why you can read different guesses at the number of people who will die early in a pandemic. But in a real pandemic the pattern will always be more complicated. With these kind of numbers health services come under stress during a pandemic. Primary care can be stressed additionally by people who are anxious and seeking reassurance or if it is decided to make antivirals available to everybody who becomes unwell.
This can be made even worse by staff who will be off sick themselves or caring for others. That is why planning is so important and fortunately health services in many countries do such planning all the time, planning what they will do with different crises, major accidents, bombs going off, etc.
However a pandemic is especially difficult because it runs on and affects all the health services in every part of the country. But pandemics have been planned for in every European country to greater or lesser extents. That depends on how bad the pandemic is, but they can be. Certainly one as bad as would affect services. However again that is why planning for a pandemic is not just in the health services.
Pandemics do not come in a standard size. Of the three pandemics that took place in the 20th Century, those of and were roughly as severe as each other in terms of the numbers of additional deaths attributed to them but they still differed considerably in their other characteristics for example the most affected groups.
The pandemic was far worse than the other two while the first pandemic of the 21st Century, in , was considerably milder. We simply do not know and there is no way of knowing. An influenza pandemic could start this winter, it could start next summer or it might not happen for more than five or ten years from now. Influenza viruses are inherently unpredictable. However, this is just one of several ways a pandemic could start - as we saw in when a swine pig influenza virus resulted in an A H1N1 pandemic starting in the Americas.
This is work underway now to determine which of the animal viruses are more likely to undergo pandemic change and which should be prepared for. But this is certainly not a matter of making predictions. Public health officials are concerned by the unprecedented worldwide outbreaks in poultry with A H5N1 viruses for at least three reasons. Firstly this strain is persisting among domestic poultry in a number of countries where poultry and human are in close contact, therefore there is a constant risk or humans being infected and the virus adapting to them.
Secondly this virus has already shown the ability to infect and adapt to a number of quite different bird species, which is unusual. Thirdly in the few humans that have been infected by these viruses, they cause severe disease with a high mortality, much higher than it is usually seen when animal influenzas infect humans - although to date these viruses have not been at all efficient in their human to human transmission.
Therefore there is some risk that through mutation or recombination the H5N1 becomes the next pandemic virus, and if it did it might be an especially severe pandemic. But the longer it is around, the more potential there is. What is therefore especially worrying is that H5N1 is now deeply embedded in poultry in a number of countries despite many attempts to eradicate it there.
Fortunately to date the high biosecurity levels in the EU and EFTA countries have stopped it becoming embedded in the poultry in our Member States, though it is known to be carried by certain wild birds like ducks and waterfowl. Probably not. We don't know. That's why I say that, when we're talking about a severe pandemic, something as bad as or worse, it's not when but if.
Precisely because and were so forgettable, the claim that future pandemics are inevitable is often heard as a claim that severe pandemics are inevitable. And that's just not true. Or it may be heard as a claim that the influenza strain that currently dominates news coverage, H5N1, will inevitably launch a pandemic.
That's not true either. H5N1 has been around at least since without becoming capable of efficient human-to-human transmission. Does that mean that it probably won't? H5N1 has proved incredibly deadly to both poultry millions and people scores. Does that mean that if it becomes capable of efficient human-to-human transmission, the pandemic it launches will be a severe one?
We don't know that either. Right now is the first time we've ever been able to watch closely as a new bird flu strain either does or doesn't lead to a human pandemic. So we can't say whether H5N1 is acting like past bird flus that later launched bad pandemics, or past bird flus that later launched mild pandemics, or past bird flus that never launched pandemics at all.
In recent months there have been a few news stories on the theme: "Whatever became of the bird flu scare? How come the predicted pandemic didn't happen? Pandemic preparedness advocates blame these sorts of stories on the short attention span of the media. If reporters and the public earlier got the impression that a severe H5N1 pandemic was imminent, they got it from us. The misimpression that the risk was necessarily imminent and the misimpression that the risk is now past are identical twins.
The first gave rise to the second. The first principle is to acknowledge uncertainty. An overconfident risk communicator is likely to generate skepticism in the audience even before the truth is known. And if the truth turns out to be different from your confident prediction, trust in you erodes.
That doesn't mean you shouldn't make predictions. It means your predictions shouldn't sound more confident than the facts justify. Talk about H5N1 the way weather forecasters talk about a distant hurricane.
It might be headed our way—or not. It might strengthen—or weaken. We need to track it closely, stockpile essential supplies, and make contingency plans. Will it be category 5 or category 2? Will it hit here or go elsewhere? It's not when, but if. Antiviral drugs are recommended to treat seasonal influenza in people who are very sick or who are at high risk of serious flu complications. These same drugs may be useful for treating pandemic influenza, depending upon whether the pandemic influenza virus is susceptible or resistant to available antiviral drugs.
Antiviral drugs are prescription drugs they are not sold over-the-counter and are different from prescription antibiotics that treat bacterial infections. Nonpharmaceutical interventions, or NPIs , are actions, apart from getting vaccinated and taking medicine, which people and communities can take to help slow the spread of respiratory illnesses, like pandemic flu. Again, these actions do not include medicines, vaccines, or other pharmaceutical interventions. Given that it may take months to produce a pandemic flu vaccine not included in the pre-pandemic vaccine stockpile and that antiviral drugs may be reserved for treatment, NPIs will likely be the only prevention tools available during the early stages of a pandemic and, thus, critically important to help slow the spread of infection.
NPIs , also known as community mitigation strategies, may be more efficient when used early in a flu pandemic and in a layered fashion. Public health officials will recommend that people practice everyday preventive actions at all times. These actions include staying home when sick, covering coughs and sneezes with a tissue, washing hands often, and cleaning frequently touched surfaces and objects.
During severe, very severe, or extreme flu pandemics, public health officials may recommend additional actions, such as using facemasks when sick and in close contact with other people, temporarily dismissing child care facilities and schools, and increasing the space between people and decreasing the frequency of contact among people that is, social distancing.
CDC has developed an updated set of guidelines, called the Community Mitigation Guidelines to Prevent Pandemic Influenza — United States, , supplemental plain-language guides for specific community groups, and online communication and education materials that outline strategies for planning and preparing for a flu pandemic and for using nonpharmaceutical interventions NPIs. A novel influenza flu virus is an influenza A virus that has caused human infection and which is different from current human seasonal influenza A viruses.
Any novel influenza A virus , such as those of avian or swine origin, has the potential to cause an influenza pandemic. Some novel flu A viruses are believed to pose a greater pandemic threat and are more concerning to public health officials than others because they have already caused serious human illness and death and also have been able to spread in a limited manner from person to person.
Novel influenza A viruses are of extra concern because of the potential impact they could have on public health if they gained the ability to spread from person-to-person easily and thus trigger an influenza pandemic. Examples of novel influenza A viruses of extra concern because of their potential to cause a severe pandemic include avian influenza A H5N1 and avian influenza A H7N9 viruses. These two different avian influenza A viruses have caused sporadic human infections, some limited person to person spread and resulted in critical illness and death in people.
Influenza viruses that normally circulate in pigs also have infected people ; these viruses include influenza A H1N1v , H1N2v and H3N2v. Limited, unsustained spread from person to person also has been detected with these viruses, but in general, these variant viruses have been associated with less severe illness and fewer deaths than avian influenza viruses.
In general, human infections with H5N1, H7N9, H1N1v, H1N2v and H3N2v viruses have occurred rarely, but if these viruses were to change in such a way that they were able to infect humans easily and spread from person to person in a sustained manner, a flu pandemic could result. Skip directly to site content Skip directly to page options Skip directly to A-Z link.
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