How do vaccines work?

/ Medsana News / By

Firstly, how does your immune system work?

Your immune system is your body’s natural defence mechanism against the germs you encounter every day. We call these harmful germs antigens. Antigens may be bacteria, virus, fungi, or another type of foreign substance. Your immune system recognises antigens and mounts an attack against it to remove it from the body and prevent infection. Once your immune system has encountered a specific antigen, it remembers it by generating memory cells.

So, how do vaccines work?

Vaccines expose your immune system to a weakened or killed version of an antigen, one that cannot cause infection but can generate these memory cells. If you encounter the same antigen again, your immune system remembers this antigen and rapidly produces the specific antibodies to destroy it. In some cases, you may still get a less serious form of the illness.

Natural immunity occurs when you become infected with an antigen and develop immunity through memory cells as outlined above. Vaccines are a clever way to gain immunity without ever having to be infected. Using weakened versions, killed or parts of antigens that cannot cause infection, we can help our immune system learn how to fight these infections better in the future.

4 Main Types of Vaccines

1. Live Attenuated

The whole antigen is used, but it has been weakened to make it less pathogenic. It can simulate an immune response and create memory immune cells but is not strong enough to cause disease. Measles, mumps, rubella, varicella, rotavirus, smallpox, and yellow fever are live attenuated vaccines. These vaccines should be avoided during pregnancy due to temporarily weakened immune systems.

2. Inactivated

The whole antigen is used, but it has been killed in the laboratory using heat or formalin. Inactivated antigens do not simulate an immune response as strong as live attenuated vaccines, and as a result, these types of vaccines often require booster shots to maintain immunity. Hepatitis A, polio, rabies and influenza are inactivated vaccines.

3. Subunit

Only a fraction of the antigen is used, like polysaccharides or proteins. These vaccines use the portion of the antigen that the immune cells respond to. Hepatitis B, human papilloma virus, Bordetella pertussis and varicella zoster are subunit vaccines.

4. Toxoid

These are vaccines that create immunity against the toxin produced by the antigen rather than the antigen itself. Examples of these are the tetanus vaccine, which protects against the tetanus toxin produced by the bacteria Clostridium tetani, and the diphtheria toxin produced by the bacteria Corynebacterium diphtheriae. For these vaccines, the toxin is deactivated with heat or formalin.

 

We recommend following the immunisation schedule to protect yourself and the community from preventable diseases. Please call reception on 07 3852 4878 to book a consultation with one of our General Practitioners.

 

The information in this article has been adapted from:

Health Direct, Immune System https://www.healthdirect.gov.au/immune-system accessed 1st July 2021

Australian Government Department of Health, How does immunisation work < https://www.health.gov.au/health-topics/immunisation/about-immunisation/how-does-immunisation-work accessed 1st July 2021

World Health Organisation, Types of vaccine https://vaccine-safety-training.org/types-of-vaccine-overview.html accessed 1st July 2021

This article was written by April Stevens BSc. MD student. 

5th July 2021.

 

Timely PCR Swab Service

Available between 8:30am – 9am

 

  1. Short Telephone Consult with the patient – bulk billed if Medicare eligible. Private fees with no Medicare rebates apply if the patient has not seen us in the last 12 months.
  2. The doctor will request a respiratory panel for viruses and bacteria (where clinically appropriate).  For example, Influenza, Covid, RSV, mycoplasma, pertussis and so forth.  Not all possible infections are on this panel.  The doctor may decline the request if it is not appropriate and direct the patient accordingly.
  3. Normal fees will apply if more than swabbing is requested.  Clinical examination and other requests requires a normal consultation at another time.
  4. Patient arrives at the car park next to Building 10 before 11am.  Or takes the pathology request to another 4Cyte collection centre.
  5. Patient calls reception to notify of their arrival so the 4Cyte Pathology Collector can gown up and go the patient’s car to swab the patient.
  6. PCR swab gets sent to 4Cyte.  The processing times varies according to workflows.
  7. 4Cyte will SMS the patient with the Covid results.  Positive PCR test results for other respiratory viruses or bacteria are not named.  A negative PCR result doesn’t mean the patient is infection free.  These swabs narrow down the possibilities and guide appropriate treatments.
  8. An appropriate appointment needs to be made for results in person, via video or via phone.  Normal fees applies for these consult.  Normal fees applies if the doctor calls the patient for further clinical advice and management.  
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