What about Swine Flu?

I know that swine flu has been headlining the news for several weeks now, and you may be sick of it (no pun intended), but I thought I would take this opportunity to give out the important information. Swine flu, or novel H1N1 as it is now being called, is simply a new strain of influenza that appears to be currently circulating. Preliminary data indicates that it likely began circulating in humans in Mexico in recent months.

So what makes this influenza different, and why are we hearing so much about it? We know that this is a new influenza with antigenic lineage that we have not seen before in humans. This means that the community at large does not have immunity to it, therefore, a much greater proportion of the community is likely to become infected.

As infectious diseases go, influenza affects the greatest proportion of our population each year, particularly during certain months. The Centers for Disease Control and Prevention estimate that approximately 400,000 people are hospitalized in the U.S each year due to influenza, and 35,000 – 40,000 people die. As you can imagine, the private and public health community dedicates a great deal of time and energy toward influenza surveillance so that we can best prepare and protect our communities. Local health departments work with hospitals, clinics and medical providers in cities and towns throughout the country to collect specimens from people who are infected with influenza each year, so that the strains that are currently infecting people can be identified. Through this process, antibodies specific to the flu strains that are circulating can be included in the influenza vaccine being manufactured for the next flu season. I find this process to be amazing and fascinating, and I view it as a sort of Santa’s workshop for flu protection.

Still, we need to know why this swine flu issue is ruffling so many feathers. As I said earlier, this flu is a new strain, and it has not previously circulated in humans, so the population at large does not have any immunity to it. First of all, why are health officials calling it H1N1? Every flu strain that circulates has an H and an N included in its name, which stand for Hemagglutinin and Neuraminidase, two proteins that are found in the virus. The H and the N are each followed by a number that identifies the specific glycoprotein. This gets more complicated to explain, but what you should know is that all flu strains are identified by these letters and numbers; H and N are not unique to this swine flu. The current swine flu that has been circulating in humans is an H1N1. You should also know that most of our influenza strains originate from pigs and birds.

Early information on this novel H1N1 does not indicate that it is any more virulent or pathogenic than the flu strains we have been seeing each year; it is simply a new strain. It is not incredibly infectious, and it is not causing more severe disease than our recent influenza strains. The majority of the people who have become severely ill from the novel H1N1 had predisposing conditions that complicated their influenza infection. We expect a certain amount of severe illness to occur from all flu strains. The people most susceptible to getting severely ill are the very old, the very young and those who are immune compromised — including people with HIV. We also know that the novel H1N1 is susceptible to the antivirals that we have. Antivirals are know to reduce the severity of illness and the length of time that someone is ill. In some cases, they may provide protection from infection.

We have been expecting a new strain of influenza to emerge for several years now. History shows us that there have been some years where a new influenza strain emerged, and people had little to no immunity. With an absence of immunity, a significant proportion of the population was ill and a greater than normal proportion became severely ill or died. Two examples where this occurred are the flu pandemics of 1918 and 1957. Researchers have determined that we have been due for the emergence of a new influenza strain, and now it has.

One cause for concern, however, is the possibility that the current strain will mutate. If a susceptible host, such as a human, becomes infected with the novel H1N1 and he or she is also infected with another common influenza strain such as H3N2, the DNA from the two strains could merge and create a stronger virus that may not respond to our current supply of antivirals.

What should you do? First … don’t panic. Just be more vigilant with your personal hygiene. Influenza is spread through droplet transmission during coughing and sneezing. If you are ill, do not go to school or work, and try to isolate yourself from others. If you know someone who is ill, avoid contact with him or her as much as possible. Most importantly, wash your hands more frequently. The CDC expects to have a vaccine available in the fall that will provide protection from novel H1N1. The Salt Lake Valley Health Department also encourages everyone to get the flu shot every year.

If you have any questions about influenza, you may call the Salt Lake Valley Health Department at (801) 534-4600.