Acquired Immunity

Definition of Acquired Immunity
The Immunity acquired after exposure to a pathogen. A pathogen is any type of organism which has the ability to make us ill; bacterial, viral, fungal etc. Acquired immunity develops when we acquire antibodies to specific pathogens in one of two ways:

  1. we contract an infection, usually viral, (red measles, chicken pox, German measles - rubella), or a bacterial infection, like whooping cough - pertussis.
  2. we are immunized by vaccines, usually injected.

When people contract viral illnesses, ( chicken pox, German measles etc). or bacterial illnesses, i.e. whooping cough, they usually developed life-long immunity. Circulating 'memory' white blood cells work together with lymphocytes to create antibodies which persist for long periods and confer immunity to those illnesses.

How we acquire immunity immunizations

  1. Immunizations create immunity by taking part, or in some instances, all, of the pathogen for which immunity is desired, and killing it or altering it in such a way that it should not cause illness when it is injected or ingested, and our body’s innate immune system is activated.
    Once activated, the protein in the immunization turns on immune cells. This stimulates the production of a dizzying number of substances which attach themselves to the invading organism. These substances secrete killing chemicals to destroy them; blast them, eat them up, chew them up and spit them out. In this process, information is sent to lymphocytes and other cells which create antibodies to the pathogen. Then, should the person encounter the pathogen in the future, i.e. German measles, they will be immune and not get ill.

The perfect immunization would create antibodies in sufficient numbers to prevent that infection from occurring and would have no side effects. Unfortunately, this is not usually the case with our current vaccines. Not everyone who receives the vaccine will develop antibodies thus not become immune. For some people, following immunization, a reaction or an illness ensues - often mild but occasionally severe. Earlier, when whooping cough immunization was administered to infants, one of the relatively frequent side effects was seizures. Subsequently, this immunization was improved and the side effects are fewer. It is likely that other problems exist for some people because often immunizations are preserved with stabilizing ingredients (formaldehyde and mercury), and substances to provoke a longer or more intense immune response (aluminum). One subject currently being debated is a possible link between measles, mumps, and rubella (MMR) immunization and autism.

Any Problems with immunizations?man who resists immunization

When scientists working with the pharmaceutical industry attempt to create an immunization for viral illness such as influenza, they select examples of the flu of previous years and try to predict which types of flu will happen in the year to come. If they guess correctly, the people who receive that immunization should, theoretically, either not get ill from that virus or have a much less serious illness.

Unfortunately, often the guesses are wrong. Sometimes, while the 'guess' has been accurate at the time it was made (months before the flu season), the immunization will fail to protect as intended because, in the interim, the viruses have changed identity enough that the antibodies created by the immunization are not at all, or minimally, effective. People who have been immunized with that year's influenza vaccine may then get the flu, and be disappointed with the outcome.

Immunization for Swine Flu (H1N1)

Unfortunately, this is currently under debate by scientists and clinicians, as well as political / bureaucratic agencies. Opinions abound about who, and if, specific groups of people should be immunized and if it is safe to do so. You will have to read about different points of view and make your own decision about this important point.

Immunization for Avian flu

A great deal of attention is now focused on prevention of Avian Flu (H5N1) because of fears that it could herald the outbreak of a world-wide and lethal influenza outbreak.

At the moment however, this virus has not infected people other than agricultural workers who are exposed to birds, or laboratory technicians working with the virus. I am not aware of any cases where the virus has been transmitted from person-to-person. Public Health workers are trying very hard to prevent this influenza strain from spreading because it is so very virulent and so many people who contract it die. Despite best efforts, avian flu keeps popping up in different locales, mainly in South Asia but it has also been found in various location there and in Europe.

man with gas maskAnyone who was in Toronto during the SARS outbreak in the early 2000's will remember the deaths and the siege mentality and the fear that resulted from it.

If scientists therefore create an immunization to this particular virus (H5N1) it could be useful for agricultural workers who could be exposed to infected birds. However a vaccine for this particular virus (H5N1), in its current form, would not offer protection if the virus mutates. If this virus changes into a form that passes from person-to-person, it would take months to produce a vaccine effective against the new virus. In the meantime, many people would have succumbed.

So we can't count on medical science to protect us in this way. Our best chance of defeating illness, should a pandemic develop, is to have a strong innate immune system.

flu Tamiflu

(Oseltamvir phosphate - Roche) has recently been introduced and is now being promoted as a possible "help" in dealing with an Avian flu pandemic. In the manufacturer's indications for its use is the statement, "There is no evidence for the efficacy of Tamiflu in any illness caused by agents other then influenza viruses Type A and B. Data on treatment of influenza B are limited."

In order to be effective, Tamiflu is required to be administered within 48 hours of the onset of symptoms. This medication has never been assessed in the treatment of a coronavirus (avian flu belongs to this category of viruses as does SARS). Many clinicians with experience with this medication are unsure of its benefits. There may be only a minor improvement in flu symptoms or perhaps a shortening of symptoms, at best, by about three days (most flu's last about 10 days).

There is also emerging data that some people who take Tamiflu could become quite ill, possibly from the medication.

Why influenza is such a concern

One of the clinical concerns with influenza is the effect it has on diminishing immunity, and the development of subsequent infections. For example, pneumonia may follow viral infections. As illustrated in this microphotograph. the healthy respiratory lining becomes swollen during, and after influenza. This swelling makes the respiratory passages largely useless at resisting further infection. Its ability to clear mucus and resist bacterial invasion is markedly hampered.

The image below, on the left, shows healthy cilia which sweep pathogens upward toward the mouth and support immune function. The image on the right shows swollen, ineffective ciliae. They have been damaged by influenza. Because of this damage, they work less effectively to eliminate mucus. This increases coughing. They are also less able to clear bacteria - probably the reason there is sometimes pneumonia after the flu.

Effect of influenza A.

You might be interested in reading more about respiratory immunity now.

There have been no studies which report on the effect of Tamiflu® on this issue. Taken as a whole, it is hard to imagine that this medication could possibly be of any real benefit to large numbers of people in a pandemic. Some skeptics have pointed out that promoting Tamiflu® as a solution to a pandemic could possibly be a profit making tool promoted by the pharmaceutical industry. It is difficult to know the truth of this. In any case, your best defense against a virus is having strong innate immunity.

Please read on to learn more about Digestive immunity: Next