COVID-19 Vaccination Advice

COVID-19 Vaccinations @ Saltfleet Clinic

COVID-19 Vaccination Advice with our Specialist Public Health Physician

Dr Bob KassMBBS MRCP MScMCH DCH FAFPHM

 

Please note our Specialist Public Health Physician is not a GP. Please DO NOT enquire about GP services.

 

Your COVID-19 Vaccination will need to be separated by a minimum of 2 weeks from any Flu Vaccination.

Advice may change at any time and it is important for everyone to keep abreast of developments

https://www.health.gov.au/covid19vaccines

 

The COVID-19 Vaccination roll-out started in South Australia on March 22nd 2021.

Media commentators often use the term Post COVID. Unfortunately, there is no post COVID. COVID-19 will remain a significant health concern for the foreseeable future. This is how novel infections behave in the community over time. COVID-19 is no different.
 

At this stage, I recommend that you do NOT participate in any media hype about herd immunity or efficacy or whether a one particular vaccine reduces transmission more than another.  These aspects are important but shouldn’t take centre stage for the moment. 

 

COVID-19 Vaccination Information
Be careful about sourcing your information from social media. We have 2 expert groups overseeing new therapeutic agents. These include:

Both ATAGI and TGA have served the Australian community very well over many years. ATAGI oversees our very successful National Immunisation Plan (NIP). Both groups will play important roles in the vaccine roll out. Listen to their advice and if you have any concerns seek more information from your health care providers.

 

Be careful of social media. Education via the media is obviously important but there are times when you should turn off.

Herd immunity in perspective

Just a brief note about herd immunity and vaccine efficacy to put things in perspective.


We have provided the Influenza vaccine as a government funded vaccine for over 20 years. The actual vaccine has been available since the mid-1940s.  At no time have we ever achieved herd immunity. Nor was it expected. The efficacy of the flu vaccine lies somewhere between 30 and 70% depending on whether the vaccine is a good match for the circulating strain. Despite this, studies show it reduces hospitalisations by 40% and admissions to intensive care by over 80%. 


My other example is the Measles vaccine.  This excellent vaccine was introduced into Australia in 1968 yet it wasn’t until 2012, 44 years later that we could say there was no circulating Measles.

 

Covid19 Vaccines

The Federal Government has purchased supplies of 3 vaccines. The first 2 have been cleared for use by the TGA and are currently available to certain groups. The third has completed phase 3 trials but unlikely to be cleared by the Therapeutic Goods Administration (TGA) until later in the year.


The three vaccines are all different and we are very fortunate. The first 2 are being used extensively in the UK and Europe. Under normal conditions it would take years to develop and approve a new vaccine. To have 3 available in under 12 months is quite extraordinary. 

About each Covid-19 Vaccine...

Pfizer-BioNTech

The Pfizer-BioNTech vaccine is a messenger RNA vaccine (mRNA). This type of vaccine is relatively new. This vaccine is currently the preferred vaccine for those under 50 years. The vaccine delivers genetic material for the viral spike protein to the body cells.  In other words the vaccine teaches our cells to make a “harmless protein” that is a look alike for the spike protein on the virus. Remember it is the spike protein that allows the virus to attach itself to various cells in the body. The original genetic material is then broken down while the newly developed protein remains attached to the cell.  Since the protein is “foreign” to the body it starts a chain of events culminating in the development of antibodies against the protein.  This process takes time but should the individual be exposed to this particular protein in the future it is hoped the circulating antibodies will quickly provide defences against it. At no stage is the vaccine recipient exposed to the COVID-19 virus.
 

It is still unknown if mRNA vaccines provide memory cells to produce future bursts of antibody and at this stage it is also unknown whether the Pfizer BioNTech vaccine will provide mucosal immunity in the upper airway. This would appear to be important to reduce transmission from an immunised individual. We do, however, know that it produces good immunity in the lower airways and this is very important in protection against serious viral pneumonia. It most likely protects other organs in a similar way. 
 

The recommended schedule is 2 doses separated by 3 weeks. This may change based on overseas experience.

 

Oxford-AstraZeneca

The Oxford / AstraZeneca vaccine is a viral-vectored vaccine. This vaccine has been extensively used in the UK and Europe. Concerns have recently been raised about an association with a rare clotting disorder, particularly in young people.

 

ATAGI now advises it for those over 50 years who fit the roll out schedule criteria at the time – 1B (March/April 2021).  It can be used as a booster in those under 50 if a previous dose has been given and there were no issues. 

 

Australia is in a very fortunate position of having no current community transmission of COVID-19 and a vaccine program must always take into account the true risk of the disease against any possible adverse events related to a vaccine.

 

It is important to note that the AstraZeneca vaccine can be considered in adults under 50 years where the benefits outweigh the risks and the individual has made an informed decision based on a good understanding of the risks associated with the vaccine. 

 

This type of vaccine has been explored previously for a number of infectious diseases including, Zika, Chikungunya, MERS and plague. The vaccine uses a non-replicating Adenovirus to carry genetic material to body cells. The virus genome has been modified to carry the sequence for the COVID-19 spike protein. The virus itself cannot cause disease or replicate in body cells. The body cells use the genetic material to produce the spike protein. Studies show the body recognises this protein to be foreign and produces our natural defences to disease, antibodies and T cells, to fight against the virus. Antibodies are the first line of defence in the body and T cells provide memory should there be exposure to this foreign protein in the future. It is a very clever way to provide natural immunity in an artificial way.


Vaccination protects the individual from serious disease. Good protection is achieved by 23 days. It’s role in reducing transmission is yet to be formalised.  Viral loads are most likely much lower in vaccinated asymptomatic carriers of COVID-19 and hence transmission would also be expected to be lower.   Vaccination may indeed have some role in reducing this transmission.  

 

The recommended schedule is 2 doses with a gap of 3 months.
 

Novavax

Novavax is the 3rd vaccine pre-purchased by the Australian Government.  51 million doses have been secured. It is an exciting prospect but unlikely to see approval before the middle of the year.

 

Novavax is a protein subunit vaccine with technology quite different to the other candidates. This subunit approach has been used in vaccines against the Human Papilloma Virus (HPV) and Herpes Zoster (Shingles). We are also hoping for a vaccine against Respiratory Syncytial Virus (RSV) using this technology. It has been over 5 years in the making. The body of knowledge has helped to expedite the process with Novavax.


Novavax vaccine is also based on the Spike protein of the virus. The genetic information is transported by a non-human virus into a lab grown insect cell which responds by producing a large amount of “harmless spike protein”. The protein is harvested then combined with an adjuvant (Matrix- M1) prior to vaccination. This adjuvant has been used in the past and no issues have been identified. There is no exposure to a live virus at any time. The vaccine recipient responds to the “foreign protein” by producing antibody. If the individual should be exposed to COVID-19 then the antibodies would bind with the spike protein of the virus making it impossible for it to attach to the cell receptors of the individual. It is a very clever vaccine.  


A British study has shown it to be almost as effective as the Pfizer vaccine (> 90%) and it seems to work well against the variants apart from the South African one. Work is under way to provide better protection for this variant with a booster shot.
We look forward to the progress of this vaccine through the registration process.

Conclusion

COVID-19 has wreaked havoc globally over the past 12 months. With almost 140 million cases and 3 million dead we must be thankful for our current position in Australia. The advantage of being an island. 


From a physician’s perspective I am very appreciative for all the free access I’ve had to research papers and personal insights from around the world. I have never observed such international collaboration in the past. At least we can say something positive has to come out of this pandemic.


Dr Bob Kass
Public Health Physician

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