Q: Why should I get the flu vaccine? I’m not in a risk group and they get the vaccine wrong sometimes anyway. And by the way, what is the deal with H1N1? I am pretty skeptical about that new vaccine. Is it safe?
A: Influenza is an Italian word that means influence. The family of viruses we are all familiar with was given this name because it was thought these recurrent illnesses were due to the influence of the stars — or driven by astrological influences. The name stuck; in fact people commonly refer to any crummy illness as the flu — “Larry has the flu, he is throwing up all over the place.”
Actually, influenza is primarily a respiratory illness due to viruses from the Orthomyxoviridae family. Influenza viruses are quite needy. They can survive on their own for a while, but for them to really reach their nasty potential, they need help. The viruses are not equipped with the gear to reproduce; for that they need other living organisms. That’s where we come in. An unsuspecting human grabs a doorknob and gets some virus on their hand, then they rub some mucous membrane like their eye. The viruses then latch on to the mucous membrane cells using specialized grappling-hook proteins called Hemagglutinins (the H in H1N1).
The viruses then travel into the control room of the cells and hack into the genetic hardware of the infected cells, turning them into factories for their offspring. The newly replicated viruses then move towards the surface of the infected cells and use their Neuraminidase proteins (the N in H1N1) like machetes to slash themselves free from the pirated cells — and away they go to pillage and plunder the neighboring cells.
Soon there are many hurting, slashed cells calling for inflammatory help from the immune system. This stirs up a mess of inflammation, making us ache, ooze, weep and whimper. When we cough or sneeze, away the virus flies onto another doorknob or onto grandpa’s toothbrush — and so on and so on.
Strains of influenza viruses are categorized based on the known 16 flavors of Hemagglutinin proteins, and 9 flavors of Neuraminidase proteins mentioned previously. So there are an incredible number of variations — for example H1N1, H3N2, H5N1, etc. To further complicate things, if you look at the genetic passports of these various strains, you can find where the viruses have traveled, and in whom — for example they may contain genetic stamps from humans, swine, birds, etc.
Every year an attempt is made to guess which three strains of flu are going to be most likely to infect humans. From this best guess a vaccine is produced. The purpose of the vaccine is to prime the immune system in the recipient to prevent an infection from running rampant in the host.
About half the time, the match is not ideal; those are years when we may get the flu despite being vaccinated. You absolutely cannot contract the flu from the injectable vaccine — the virus has been inactivated.
So why should a perfectly healthy young person bother with a flu vaccine? Consider it your civic duty. Imagine that the role of a vaccine is like distributing a most-wanted poster that needs to be photocopied millions of times by the immune system to use to identify the virus. Compared to a healthy child or adult, the photocopier of an infant is a bit like a Fisher Price “My First Copier” model and is not very efficient at putting out the copies. The photocopier for a person over 65 can be quite outdated and less efficient as well — maybe it even uses a hand crank. That is why it is important to protect the vulnerable — the very young, and very old, and people with underlying health problems — by immunizing the vectors, or those who are the most healthy and active, and the most likely to carry the virus to the vulnerable. (Think school-age kids and business people too busy to wash their hands.)
There is emerging evidence that this utilitarian approach to protecting the vulnerable by vaccinating vectors is the way to go (while still vaccinating the vulnerable of course). A striking example of this theory can be seen in the experience of Japan. For approximately 25 years between the 1960s and the 1980s in Japan, almost all school children were vaccinated for seasonal influenza. During this period there was a stable mortality rate due to influenza and pneumonia, despite the proportional aging of the population. This program ceased in the ’90s, and a dramatic increase in deaths from influenza and pneumonia was observed.
The authors of the study estimated that for every 500 school children vaccinated, one life was saved. If we extrapolate this to the billions of doses of influenza vaccine given worldwide over the past 50 years, we are talking about millions of lives spared.
In addition to the seasonal epidemics of influenza seen every year, about three times a century there are pandemics of influenza virus that break all the seasonal rules. Their great infectivity is probably due to the fact that they are novel strains that few people have had any exposure to. That is what is going on right now with the pandemic H1N1 2009 novel flu of swine origin. Because pandemics infect huge numbers of people, the vulnerable have a much higher likelihood of exposure, and so there can be grave consequences.
Many folks have expressed concern that the vaccine for the H1N1 flu is somehow unsafe, often comparing it to the swine flu vaccination program in 1976. That swine flu strain turned out not to cause much suffering or illness — if it had, there probably would be less of a fuss over the relatively small number of complications from the vaccine. For every 100,000 doses of the vaccine given, there was an estimated one extra case above population baseline of Guillain Barre syndrome, which is a known risk of flu vaccination. Forty million doses were given and 400 cases of GB is a lot when no one really got sick from the illness the vaccine was preventing. It should be noted that while Guillain Barre is a serious illness, most people experience a complete recovery.
However, the H1N1 flu strain is already a more significant threat with more significant consequences than the illness in the ’70s. And it is worth noting that the production of the H1N1 vaccine is no different from any other flu vaccine — it would have been included in your seasonal flu shot if it had appeared earlier.
While we may still be waiting for a pandemic vaccine to be available, the seasonal vaccine is available, so don’t wait. Hopefully soon we will have available a safe and effective vaccine to prevent the pandemic strain as well. Good luck, stay well and stay home when you are not.