Tag Archives: flu season

What is Flu Vaccine Anyway?

We spend a lot of time each fall talking about influenza and flu vaccine. A great deal of hard work by very smart people goes into making this magic fluid each year.

'Flu Vaccination Grippe' photo (c) 2010, Daniel Paquet - license: http://creativecommons.org/licenses/by/2.0/

The first thing you need to make flu vaccine is a flu virus. Those come in many different flavors, some old standbys trying to make a comeback, occasionally some new virus. Because the earth is tilted, our summer is the Southern Hemisphere’s winter. They are having this year’s flu season 6 months before we do. The best place to look for new influenza viruses are poor rural areas in Southeast Asia. In these areas, humans and animals frequently live close together. I’m sure you have noticed all influenza viruses have animal names (swine flu, bird flu…) – that is because the virus jumped from an animal to a person.

The World Heath Organization (WHO) is in charge of collecting flu viruses. They culture a bunch of sick people (nasal swab) to find the new and dominant viruses that season. They get pure cultures of the three worst viruses.

Now the magic begins.

Each virus is combined with a harmless standard lab virus. The result is a new virus that looks like the bad influenza virus on the outside, and like the harmless lab virus on the inside. That is important because the human body generates antibodies to the outside of the virus (it can’t see the inside). Now we have a copy of the virus that can’t make people sick, and grows well in chicken eggs. All this happens at the WHO labs.

Next it’s off to the vaccine manufacturers.

This harmless copy virus is injected into fertilized chicken eggs that are 9 to 12 days old. Three days later there are almost countless copies of the virus in the egg white. The virus is then separated from the egg white. Now it’s time to kill the virus with chemicals as we don’t want anyone being infected by this new virus (even though it is harmless). Now the virus is broken up to get a solution of the surface proteins (those on the outside).

This solution, called antigen, is then diluted to the proper concentration for use.

Next, it’s sterilized and packaged in vials and syringes.

There are hundreds of quality assurance tests done at each step of the process.

So your flu vaccine contains just the proteins from the outside of the original bad virus. It doesn’t have the ability to infect you as there is no living virus in the vaccine.

When you get your flu shot, these proteins (antigens) in the vaccine stimulate your body to make antibodies against this interloper. These antibodies will attach to the original virus and destroy it. In about 9 days you have enough antibodies to fight off an assault by the original virus.

It takes six months from finding a new virus to mass-producing the vaccine. That original virus was found in our spring (the Southern Hemisphere’s fall) and is ready for use by our fall season – just in time for flu season.

Producing the new trivalent (3 viruses) vaccine each year is one of the things the human race does very well; it requires worldwide cooperation to pull it off.

So, when you get your flu shot this year (and do it soon to maximize your protection), appreciate the “magic” that half cc of vaccine represents.

Take care

Dr B

As the Peak of Flu Season Hits, Study Shows Importance of Hygiene

With the peak of flu season usually occurring this month, a recent study on the spreading of flu can teach us an important lesson about hygiene.

The study, published by the National Academy of Sciences, looked carefully at the H1N1 flu season in 2009. They studied schoolchildren, classmates and their families as the epidemic was happening. They suspected that many children were spreading the flu to their classmates in school.

Their findings actually disproved that school was an important source of infection. They found instead that the close contact of friends who played together outside of school was a common source of illness. Typically, children who played together outside of school have more close contact with each other. They use little hygiene such as hand washing or covering a cough.

Hand Washingphoto © 2010 Anthony Albright | more info (via: Wylio)

It was striking that children did not get sick from just sitting next to a classmate in school who was sick. This went against the prevailing wisdom of closing schools to prevent the spread of flu.

In reviewing households with sick children, most of the time adults in the household did not get sick from their children. They were probably making a special effort to limit exposure to the obviously ill family member. Again, the study results suggest the more likely source of infection was in the community at large where efforts at hygiene were forgotten or non-existent.

Day 59, Project 365 - 12.18.09photo © 2009 William Brawley | more info (via: Wylio)

We know that the flu virus does not fly through the air attacking a person over the shoulder while they look the other way. If someone coughs or sneezes on you point-blank within a couple feet, mucus droplets are broadcast with the virus; however, the most common denominator is you. We are the last link to acquire the infection. By touching our own hands to our face and mouth, we’re most likely to get the illness. Hands touch so many public places and surfaces that we forget that our own hands are such germ-laden instruments. Washing hands before eating or food preparation remains one of the most important means of protecting yourself from illness.

The researchers noted that the flu virus spreads very rapidly among school age children. The results reinforce that it is not the classroom or seating arrangement that is the problem. It is more likely due to the fundamental lack of hygiene practices in children and adults in the community that facilitate spread of the disease.

We all can learn a lesson from this study, so be sure to wash up.

– Dr. Bruce Kaler