Página en español Página no português

What do I need to know?

edit · top

What’s going on

There are actually several kinds of flu that get tossed around and mentioned together. It’s important to separate and define them, as the terms mean different things.

Seasonal Flu

Seasonal flu is either influenza A or influenza B, and generally hits the US between November and March for around six miserable weeks. The onset date differs from year to year and location to location. The annual flu shot protects you from this year’s seasonal flu only, and generally gives less-than-perfect results, particularly to the elderly. This is because flu changes from year to year. Because it takes 6 months to manufacture flu vaccine, a committee guesstimates which flu will be coming each year before the season starts. Some years they get it right, and some years they don’t.

In fact, there are subtypes within the seasonal flus. Influenza A has the most variation, and is named by the proteins on the viral envelope. There’s a hemagglutinin (the H protein), which lets the virus latch on to receptors on epithelial cells in the host’s body. And there’s a neuraminidase (the N protein) that lets the virus escape from the infected cells (see Flu Wiki’s science section for more details). There are actually 16 different Hs and 9 different Ns; only H1 and H2 and H3 occur in humans but all of them occur in birds, the natural host for flu. This year’s seasonal flu is an H3N2, for example and that’s what’s in this year’s flu shot along with influenza B and H1N1 (more about that one later). But if you see a flu referred to by the H and N, it’s influenza A.

Bird Flu or Avian Flu

If a novel H such as an H5 or H7 or H9 gets into a human, we have no defense against it because we’ve never seen it before. But birds have, and so these novel flus that exist in waterfowl and other birds (but not humans) are referred to as bird flu or avian flu (even though all flus are bird flus). The one circulating now in Asia and Africa and Europe in birds is H5N1, a particularly nasty character that kills more than 56% of those people who get it. While ducks and other birds can get H5N1 and live, it’s especially deadly to chickens and domestic poultry. It’s very difficult to catch, and even more difficult for humans to spread because the receptors in human airways for the current H5N1 are deep in the lungs of humans and not in the nose and throat. That’s one reason why, when humans do catch it, the virus does a job on human lungs (but there are other reasons for why it’s deadly, which I will not explore here, and which are not fully understood). And it helps explain why sneezing, involving the nose, doesn’t spread H5N1 easily from human to human. Since H5N1 preferentially resides deep in the lung, it’s not plentiful in nasal secretions and if spread, doesn’t latch on to someone else’s nasal passages easily. Seasonal flus are much more easily spread and are very infectious.

Pandemic flu

We don’t fully understand exactly how flu is spread, but the above basics apply. However, should something happen that would make a novel bird flu like H5N1 easier to spread, such as having the virus mutate to a form that likes the nose and upper airway receptors (so that it’s easy to catch and easy to spread by sneezing), or prefers the temperature of the human nose, it could start to spread in a human population. If the combination of a novel virus that humans aren’t immune to (from previous exposure) and easy transmission (due to factors such as are listed above), we could get a rapidly spread flu which, when it breaks out everywhere, is called a pandemic, an epidemic everywhere in the world. Pandemic flu, or panflu is the feared agent that causes a pandemic. By the way, the widespread presence of H5N1 in birds all over Europe, Africa and Asia is known an a panzootic.

This has happened before. in fact, in 1918-9 H1N1 spread around the world, killing 50 million people. There were milder pandemics in 1957 and 1968, and we really haven’t seen one since, at least on that scale. But since we get around three each century, we are due, and that’s why scientists say that a pandemic of some sort is inevitable.

The three flus (seasonal, bird and pandemic) are listed and compared here.


Now, the reason the news from Indonesia is so concerning is that we have a novel virus (H5N1) that has not just spread from birds to humans (B2H), but has spread in a family from human to human (H2H) and likely from human to human to human (H2H2H) or even perhaps H2H2H2H. This has happened on a small scale with H5N1, in Vietnam and Thailand. Although WHO has never been forthcoming about this, many of us think it’s happened in Turkey and Azerbaijan. These clusters of infected relatives could be the beginning of the chain of infection that characterizes a pandemic - or a cluster could just burn itself out, as it did in Turkey, without further spread. Or, they could just be all the humans who got the virus from the same bird. For that reason, clusters always spark an investigation to let WHO or CDC (or whoever conducts the field study) find out what’s going on. But only in the last few days has WHO flat out said H2H has occurred, even if rarely, and never in as big a cluster as in Indonesia and never in an H2H2H chain.

Furthermore, there are actions that are supposed to be taken should spread occur, such as giving everyone tamiflu, and quarantining contacts. This requires a great deal of cooperation and coordination, both of which are lacking in Indonesia. The worry is that if H5N1 starts to spread undetected, and mutates to an easily spread form, we could have a pandemic that could make 1918 look like a picnic - this, with an H5N1 flu virus that kills more than half of the people it infects (it killed 7 of 8 in the Indonesian cluster). this ‘worst-case’ scenario is what is the basis for the pandemic flu planning going on in the US. We have no vaccine against H5N1 and it would take 6 months to begiin to make some. It would take a year to get enough to be useful - and that’s assuming the vaccine worked well (the current one in experiments works rather poorly). Oh, and some of the H5N1 strains are resistant to tamiflu, and in the best of circumstances, it must be given early and in high dose.

More Information

For further reading, we encourage you to visit the website of Peter Sandman and Jody Lanard, as well as other pages of the Flu Wiki, which has many pages on preparation and planning. There are other good web sites as well, including www.pandemicflu.gov, which has a brief capsule of the Indonesia situation here, and Trust For America’s Health. This resource page has many more available websites. But wherever you get your information from, those are the basics. And understand that since we’ve never tracked a pandemic from before when it’s happened, we don’t know what to look for, exactly, or what the early signs are. Certainly, large clusters, health care workers getting ill from the patients they care for, or large numbers of reported flu-like illness are on that list.

edit · top

What does it mean to me?

  • If you care about your health, then it matters.
  • If you care about the health of others, then it matters.
  • If you have a business, then a large number of providers, workers and customers falling ill, plus a much smaller number dying and a larger number worried, all of that matters.
  • If you are into politics, then all the above matters.
  • If you’re into journalism, education, basic services, etc …

edit · top

What are others doing?

  • The World Health Organisation has written plans and is helping member countries to get ready.
  • A growing number of governments have set up pandemic contingency plans that describe the specific actions and measures to be undertaken at the national level in the event of an influenza pandemic.
  • Vaccines: According to the Center for Infectious Disease Research and Policy (CIDRAP), clinical trials of candidate H5N1 vaccines are currently under way. At this point however, it is not clear if prototype H5 vaccines will offer protection against an emergent pandemic strain. To complicate matters still further, new vaccines (like yearly flu vaccines) are grown in chicken eggs. The amount of vaccine that can be produced is therefore dependent on the supply of eggs that producers can supply to vaccine companies. And the growth process itself takes several months.

All these agents will play a role in the event of a flu pandemic. Depending on where you live, some may require your help. In the event of a pandemic, governmental support structures may prove inadequate or fail completely. It is therefore important that individuals and grassroots organizations step in and organize at the local level.

edit · top

What to do today

  • Use this and other websites to learn more about avian flu, also known as bird flu or pandemic flu. Start with the links at the top of this page or see the where to start page.
  • Share your knowledge. For example, you could support health officials in your area as they try to deal with a pandemic.
  • Think about how to make your community more resilient. Talk with others about this. Look for simple ways to increase resilience: how to keep water running, food coming in, help being given and taken, information flowing …

edit · top

What to do if there’s a pandemic

Go to the pandemic preparedness page to learn more. In the case of a pandemic, as many as 30% of your neighbors and co-workers may become ill (yes, that many), so you need to plan accordingly. If you’re used to having low inventories of perishable goods or daily deliveries at your home, you may need to adjust your routine (the delivery service may become unavailable for example). You may need to plan how to stockpile if a pandemic hits. You may need to identify who are the key workers in your business, or who may need to get scarce flu shots. Browsing through the Local and Regional Issues section may give you other things to think about that can help you prepare.

This is Tour Level I · Level II · Level III? · Level IV · Level V

Page last modified on October 12, 2009, at 03:34 PM by pogge