How does the body fight swine flu?

This is a simplified explanation of the body's immunity process. Our body has the ability to determine when some viral organism has invaded and, if it has a match to that organism stored from a prior invasion, the immune system quickly makes up a lot of the attack cells that worked in the past and destroys the invading virus particles. If it is a new invading virus that we have not been exposed to before, usually our body can make cells that can match just right to destroy the new invader in a week to ten days.

It is during the time period, when our body is matching and making the attack cells to disable ("kill") the flu, that we feel sick until our body finds the key pattern of cells that will match and destroy that specific strain of influenza. Our body "remembers" the pattern each time it makes cells that work, so any time that same flu virus comes along again, or even sometimes a similar one, our immune system wastes no time in getting rid of it because it knows already what will work. That is why once we have had a flu virus like Swine Flu before, we won't get sick from it again. Our body will already know what cells to make and will send them out to destroy the invader even before it can make us feel sick.

This is also how vaccines help our bodies build up immunity. The vaccine contains a dead or weakened form of the flu virus for our bodies to use as a template to create the right pattern of cells that will know how to destroy the normal strength live virus in the future if it tries to get in to make us sick after that.

However, if you are immuno-suppressed from transplant medications, chemotherapy, or diseases like HIV/AIDS, then the ability of the immune system to do its work to protect your body is weakened, and repeat infections by the same organisms could potentially occur, since your body's ability to make and send the correct cells to your defense is impaired.

Because flu and cold viruses mutate readily, it is possible to catch different forms of swine flu after you have had one before that is not the same exact strain. If you contract a mutated strain, after already having had swine flu, your body may be able to fight it off easier through 'cross protection', i.e., already having dealt with a similar virus before. But even if your body can recognize it as very similar, and make the same cells as before, if the pattern of cells that your body remembers and sends to the defense does not fit the new strain of the swine flu well enough to disable/destroy it, you may feel sick until the body figures out the perfect new pattern.

Your body remembers each new pattern to protect you again from that specific strain or strains that are very similar. It is believed that the current population aged 65 and older have some residual resistance to the A-H1N1/09 Swine Flu from having been exposed to a similar strain in the past (perhaps the 1930 strain). They are unusually unaffected by this influenza, when typically they are the most at risk for and have the most deaths from seasonal influenza strains.

While the immune system's ability to store patterns for previously encountered viruses explains why older people do not get sick with colds as often, or have as severe an illness as very young children and babies do, from most common colds and viral infections, if a brand new germ attacks them, then the elderly often have more trouble and can be very ill or even die from the more severe viral attacks such as those caused by new or mutated seasonal influenza strains. Because of many older people's frailty, multi-system chronic diseases, and less robust immune systems, they can have more trouble creating new patterns.

Similarly, because infants and very young children have not had any prior exposure to the common viruses, is also why it is highly recommended that newborns be breast fed. If they are given mother's milk, at least for a short period after birth, it provides a safe way for their developing immune systems to learn the patterns for the kinds of infections that are around in their immediate environment.

Information from the CDC about breast feeding your baby if you have swine flu:

"Because mothers make antibodies to fight diseases they come in contact with, their milk is custom-made to fight the diseases their babies are exposed to as well. This is really important in young babies when their immune system is still developing. It is OK to take medicines to prevent the flu while you are breastfeeding. You should make sure you wash your hands often and take everyday precautions. . . However, if you develop symptoms of the flu such as fever, cough, or sore throat, you should ask someone who is not sick to care for your baby. If you become sick, someone who is not sick can give your baby your expressed milk."

Theory Behind Vaccinations

Vaccines take advantage of the body's built in defense mechanisms. A vaccine consists of germs or viruses that are similar enough to the real germs and viruses that cause the disease to 'trick' the body into making antibodies that will fight off the real germs or viruses.