Flu Immune 500

Your case of flu starts with someone else’s cough or sneeze. You inhale droplets that contain viruses, and they attach themselves to cells of your respiratory system. Viruses have projections on their outer coats that are especially designed to attach to your cells.

An influenza virus is a spherical mass studded with stubby projections. The hemagglutinin (abbreviated HA) are projections designed to fasten to host cells and inject the virus into them. HA are like keys: they only fit particular locks, and they open them so that the virus can enter. The hemagglutinin of the flu viruses that attack humans have evolved specifically to attach to the cells of our breathing passages.

Once the HA is attached, enzymes found in the host cell cut it down the middle, and the virus enters the cell. The RNA of the virus takes over. It directs the cell to stop making products for itself, and to start making viruses instead. A virus is called a cellular obligate parasite because it cannot reproduce without taking over a host cell. In this sense, a virus is not alive.

Since it is not really alive, it can’t have motivation, but it certainly feels malevolent when you have the flu.

When the cell is filled with newly made viruses, another protein that formed projections on the viral coat comes into play. This is neuraminidase (NA). NA mops up chemicals in the host cell that would have kept the virus there. The viruses then leave, killing the cell as they go. The flu medicines oseltamivir and zanamivir are effective at this stage, because they keep the virus from spreading efficiently by attacking NA.

You feel sick, as the virus spreads through your body. But most of your symptoms are not effects of the virus but effects of your immune

system’s attack on the virus. Fever is not a sign of flu, but of the body’s response to flu. It is an attempt to make your body less hospitable to the invader, and some parts of your immune system may be more effective at a higher temperature as well.

You feel weak because most of your energy is going to fight the flu, as it should. This encourages you to rest and let the immune system work. The cough is your body’s attempt to expel virus and also to eject secretions caused by cell death. Of course, a cough can work to the advantage of the virus too, if it helps it spread.

If the virus took over and reproduced without activating your immune system, you would feel much better. But your body’s resources could be used up by the virus. Not a good thing.

Most of the time, the immune system overcomes the virus in about 7 to 10 days. If you are sick longer, you may have a secondary infection, and might want to consult a doctor. There may be lingering aftereffects with the flu, tiredness, feeling down, but soon you will be back at your old routine.