Let’s hope not, but this community of scientists, researchers and doctors is watching developments very closely and holding their breath. At stake, literally, are millions of lives around the world including, by one conservative estimate, 1.7 million in the U.S. (Note: my day job puts me in contact with people who have to concern themselves with projecting this risk, and I’ve helped write articles on this topic for risk management publications. I’ve posted on this subject in this blog here, here and here.)
You can read those posts for an overview, or do your own research (there’s plenty of it out there now) or visit this blog which is aggregating the latest details and research on a daily basis. Here, however, are the pertinent details:
The reason the H5N1 virus has created so much concern is because it is genetically very similar to the virus that created the famous 1918 Spanish Flu pandemic that is generally believed to have killed between 20 and 40 million people world-wide (one modern estimate puts the total at 100 million, however). The impact today could be even more devastating considering the world is much more densely populated now and people are many times more mobile, which could promote the rapid spread of the pandemic.
Despite the genetic similarity, an H5N1 vaccine has yet to be developed. The flu has already killed millions of birds in Asia, and led to the preventive slaughter of millions more domestic fowl. So far – and this is important – the virus has passed to humans only through animal to human contact; it has yet to take a form that allows it to pass from human to human (more potentially good news on this this in a few more paragraphs). Flu viruses, however, are very unstable and mutate easily; every influenza that affects humans – such as the strains that appear annually – began in animals and followed this path. The easiest way for the virus to mutate is to come in contact with a human or animal that already has another strain of influenza active in its body and for the two viruses to become recombinant. (Pigs, for example, have been shown to be able to host both H5N1 and “human” influenza and H5N1 has started to turn up in pigs and tigers in Asia.)
H5N1 infection so far have been mainly in Southeast Asia where many people live and work in close proximity to birds and other animals susceptible to being carriers. Approximately 40 percent of people who have contracted the virus have died.
Here’s why the current cases in Indonesia are significant: Indonesia, unlike other asian countries, refrained from wholesale slaughter of commercial and domestic flocks of poultry thought to be harboring the virus, which might explain the outbreak. While there is still no confirmation of human-to-human transmission, the number of people infected there within a short timeframe is troubling. Also, this spring there were several small outbreaks in Vietnam in “pods” of people. The course of the Spanish Flu was for a few isolated cases in the spring, followed by a quiet summer and then a rapid spread the in the fall.
On a bit more positive note, some virologists think there may be some natural barriers keeping the virus at bay in humans, as noted here:
- Its viral replication in human cells may be inefficient. There may be too few viral offspring emerging from infected cells to create a big “viral load” that can be spread through coughing or sneezing, as the human flu virus does so well.
- The avian virus is unable to lock on effectively to human cells, or more accurately certain types of human cells. The spike that enables it to lock on to the cell receptor is the wrong shape.
- Avian viruses’ natural home is the gut of birds, where the temperature is a balmy 37 degrees Celsius. The human respiratory tract, though, is 33 degrees to 34 degrees Celsius. That coolness could have an impact on how well the virus reproduces.
- Bird viruses are well adapted to evading the immune system of birds by skirting the molecular tripwires that unleash antibodies and white blood cells that destroy invaders. But they do not yet have this in humans.
This may be good news, but the spread of H5N1 to species other than birds (again, documented in pigs and tigers), and the ability of other influenza strains to make the jump to humans, still raises major concerns.
For a comprehensive look at the havoc a pandemic could create medically, politically and economically, and what can be done to reduce the risks and ultimate impact, I highly recommend you read this article by Dr. Michael Osterholm. Just because the risk is almost mind-bogglingly surreal to consider doesn’t mean it can’t happen. After all, a year ago how many people could have conceived of a tsunami big enough to devastate half a dozen countries, or a hurricane wiping out 80 percent of a major metropolitan area in the U.S.?
Here’s a report from CNN that suggests that H5N1 is resistant to Tamiflu (oseltamivir), the leading antiviral drug that countries are trying to stockpile as a first line of defense until a vaccine can be developed.
Also, Senator Bill Frist weighs in. A key quote from his Op-Ed:
If a pandemic occurs soon, we will be in a race against time to build the appropriate defenses on the fly. We cannot afford inaction. Through the Project Bioshield legislation President Bush signed last year, we began the process of preparing for biological, chemical and nuclear threats. But Congress and the administration still need to do much more.
The avian flu poses a serious risk to our nation’s health and security. Every medical worker, public health specialist, parent, and, indeed, every citizen, needs to think about how we can confront it. Right now, preparing to face a pandemic should rank very high among our nation’s priorities. And, for the safety of its people, our nation needs to act now.