Celebrity / NYJSM Consult / Gabrielle Reece

Gabrielle Reece consults Dr. Vasey and NYJSM.com

December 10, 2009

Matthew Vasey, MD

"Dr. Vasey, all of us at thehoneyline.com would like you to explain the difference between a regular flu and the swine flu. What are some of the basic things we can do to keep ourselves and our children protected? Since it is the traveling Holiday Season do you have any extra pointers on keeping safe while riding on the germ tube a.k.a the airplane? Lastly, wouldn't you agree that even though the swine flu is potent, the media has really done a good job about getting us all a little paranoid about what this flu really is, and what happens to most individuals if they catch it?"

Thank you Ms. Reece and everyone at thehoneyline.com for such a relevant question. First off, I want to mention that I think the honeyline concept is excellent and very well put together. I encourage everyone reading this to check out www.thehoneyline.com.
(Click to visit thehoneyline.com)

As for your question, there are three types of Influenza or "flu", type A, B or C sort of like three types of people with different traits or capabilities because of a different genetic makeup. Type A's characteristics which is the most concerning type allow it to be in various animals and humans, hence all the confusing numbering of "H's" and "N's". Type B is found in people. Type C is in animals and humans but it is kind of weak and isn't really concerning. Type B and C do not have any dangerous and confusing subtypes like Type A.

It's probably best to go over some background science now. Looking more closely at the Influenza Type A subtype, imagine a spherical virus with a variety of "things" called glycoproteins on its surface. These dangerous things as far as their ability to infect humans or antigenicity is concerned, are called hemagglutinin (H) and neuraminidase (N). Influenza A virus is notorious for its mutations or genetic reassortments of these antigenic characteristics. Scientists have come up with 16 HA subtypes and 9 NA subtypes ("A" is for Influenza type A). Small scale or subtle gene changes that lead to more localized outbreaks of the flu are called "antigenic drifts". Drifts are managed by seasonal flu shots which anticipate seasonal drifts of H and N.

Large scale or significant gene changes can lead to global outbreaks, or pandemics are called "antigenic shifts". The impact on the population is contingent on how infective the viral surface is and how susceptible we as humans are. If you have a flu strain that infects pigs and it modifies an infectious component which all of a sudden can infect a human, there is now a flu strain that the human population, more importantly our immune system has never seen before, a totally new H and N combination. If this new flu strain happens to be deadly to humans and easily spread catastrophe ensues. Historically, this happened three times in the 20th century along with a couple "scares", right now I would call 2009 H1N1 a "scare" and probably a descendant of the original "Spanish Flu" lineage which has weakened over the decades.

In 1918, the "Spanish Flu" infected 20-40% of the world's population and over 50 million people died, 575,000 of who were in the U.S. Yes, ... that's five hundred, and seventy five thousand people! Other less catastrophic strains followed in 1957 and 1968 killing about 70,000 and 35,000 people respectively, in the U.S. These subsequent pandemics to the Spanish Flu contained identical genetic portions and in essence were "children-like".

Here is a picture below explaining an Antigen Drift: (Managed by a seasonal flu shot)

This figure basically shows the reason why there is a seasonal flu shot. Humans infect other humans with scientifically known H's and N's. Flu trends are tracked and the predicted H's and N's for the coming season are put into the vaccine.

Here is a picture below explaining an Antigen Shift: (Potentially catastrophic outbreak that requires a unique, in this case H1N1 vaccination)

This figure basically shows three ways catastrophe may result because our human immune system doesn't recognize new H's and N's. A bird flu can directly infect a human without changing its genetic makeup (example B). A bird flu can infect a pig which can then infect a human without changing its genetic makeup (example C). A bird flu infects a pig at the same time a human flu infects the same pig, the genetic makeup changes and then can infect humans (example A in four steps).

For obvious reasons, there is tons of medical effort devoted to influenza. There may even be a Flu Twitter page or Fantasy Flu coming soon as there is weekly Flu statistic updates posted by the Center for Disease Control. (3) http://www.cdc.gov/flu/weekly/fluactivity.htm

The best things to do as far as prevention is just some common sense things like, thoroughly and courteously covering your cough (a fist in front of your mouth or a head turn is a pathetic attempt at preventing showering your environment and your neighbors with influenza particles), purposeful hand washing and avoiding sick people. There's no way around it, airplanes are a great environment for Influenza transmission, perhaps designate one of your hands to be a contaminated hand that touches stuff on the plane, and let the other hand be the one that touches your food, your Ipod, your kids, yourself, etc ... and hand sanitize your contaminated hand often. That's what I do on the NYC subway system.

While much has been made of this "H1N1 Flu", at its core, I believe the public dispensing of information to be warranted. If ever a disease could kill everyone one on earth it would do so through this mechanism of transmission and likely be an unrecognized Influenza strain. Sensationalizing and politicizing "H1N1 Flu" however, is unwarranted. Fortunately, the effects of H1N1 on the population appear to be manageable. Most, a huge understatement, people infected by H1N1 will NOT die and none will spontaneously combust. A lot of people die every year from seasonal flu itself, but they are usually the elderly. H1N1 was disproportionately killing younger people, not surprisingly those born after the last 1968 outbreak in those who had not been introduced this Spanish flu family of H's and N's which was alarming. Fortunately, the immune system is made for this and H1N1 has not produced catastrophic population effects. Typical stuff to watch out for is fever, cough, sore throat, body aches, headache, chills, and fatigue. There are medicines recommended for H1N1. Unfortunately a flu pandemic scare, television and internet (nyjsm.com now included) are the perfect storm for panic. If you're concerned, educate yourself and/or contact your health care provider of choice. For all the latest action, check out the Center for Disease Control website, www.cdc.gov!

Here are some good pages on the CDC site:

What is seasonal flu?

What is H1N1?

Who should get the H1N1 vaccine?

Don't forget to check out:

Thank you Gabrielle Reece!

Belshe RB, The Origins of Pandemic Influenza - Lessons from the 1918. Virus N Engl J Med 353:2209, November 24, 2005
National Institute of Allergy and Infectious Disease, http://www3.niaid.nih.gov/topics/Flu/understandingFlu/
Image Credits: These images are in the public domain. Please credit the National Institute of Allergy and Infectious Diseases (NIAID). Illustrator: Links Studio.
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