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COVID-19 vaccines

About COVID-19 vaccines 

COVID-19 vaccines are an important step forward in our response to the COVID-19 global pandemic. New Zealand is currently administering the Comirnaty™ vaccine (from Pfizer/BioNTech) to those at greatest risk of exposure to COVID-19, and has vaccine purchase agreements with four pharmaceutical agencies in total.  

New Zealand has vaccine purchase agreements with Pfizer/BioNTech, Janssen, AstraZeneca/Oxford and Novavax. This means there is an arrangement to buy a pre-planned number of doses of vaccines from these companies if their vaccines are proven to be safe and effective. Also, as part of a global collaboration called COVAX, New Zealand will have access to additional vaccines.  

On this page: 

See COVID-19 general information for more information about COVID-19 vaccines and special groups, the vaccination administration process and what happens after vaccination.  

How COVID-19 vaccines work 

Vaccines work by teaching the body’s immune system to recognise disease-causing organisms (pathogens) without causing illness themselves, so that your body’s immune system then has a memory of the pathogen. When you come across the infection at a later date, your body already has an immune memory to fight the infection faster.  

There are many ways vaccines can be produced, however, they all follow the basic principle of providing a harmless version or part of the pathogen to give the immune system a snapshot of the disease. Learn more about how immunisation works on the IMAC website. 

How COVID-19 vaccines have been developed quickly 

In less than a year, we have available, licensed Covid-19 vaccines. The speed of their development can be credited to an amazing international collaborative effort. 

Science has come a long way since the early days of vaccine development and we have had real breakthroughs in design - particularly with the newer RNA and vector-based vaccines leading the way. 

International cooperation supported by significant financial backing has helped overcome roadblocks that have traditionally slowed vaccine development. The different stages of development and approval usually would happen one after another, taking many years to be completed. For COVID-19 vaccines, many of these stages were overlapped and run in parallel. This reduced the amount of time needed dramatically, but still means every step was completed.  

Some of the factors enabling the rapid development of Covid-19 vaccines include: 

  • The fact that the large pivotal trials were able to enrol large numbers of willing participants easily, and because Covid-19 disease is so prevalent, clinical data was collected very fast. 

  • Manufacturing plants were built before the vaccines were finished. A financial risk before they knew if the vaccines would work but meant they were ready to scale up production rapidly as soon as the clinical trials show success. 

  • Authorisation bodies reviewed data as it arrived, to speed up the processes. 

Find out more about the speed of vaccine development.  

Information about the Comirnaty™ vaccine (Pfizer/BioNTech)  

The Comirnaty™ COVID-19 vaccine is a messenger RNA (mRNA) vaccine. It contains a small strip of genetic material encased within a lipid (fat) bubble. It does not contain any live virus.  

Once inside the cell, the mRNA works with our own cell’s machinery to produce  the spike protein that is found on the surface of the virus. The immune system, presented with the protein, learns to recognise the virus and creates a new memory. Then, if the body is exposed to the real virus, it can quickly stop illness or, at least, reduce the severity of the illness. 

Although mRNA is a piece of genetic material, it is not a piece of our genome. Messenger RNA does not enter the nucleus of the cell and cannot alter our own genetic material. Following injection with an mRNA vaccine, the mRNA in its protective lipid bubble is taken up locally by cells where the instructions to produce the virus protein is followed. This new protein then stimulates our immune system. At this point, the mRNA is broken down, ready to be recycled.  

More information on the mRNA COVID-19 vaccine: 


How effective is the Comirnaty™ vaccine? 

The Comirnaty vaccine comes with impressive safety and effectiveness data both from the clinical trials and now from extensive use in many, many millions of doses. We can be confident it has an excellent safety profile and it is highly effective against symptomatic disease. Early data shows that the vaccine is able to reduce asymptomatic infection and therefore reduce spread.  

COVID-19 vaccine FAQs 

What types of vaccines have been developed? 

Multiple types of vaccines are being developed around the world. We are familiar with some of the vaccine types, such as the protein subunit candidates, like those used in Hepatitis B and whooping cough vaccines; however, other vaccines are using newer technologies such as mRNA and viral vector vaccines. For further information on the types of vaccines that are being developed, please click here

How are COVID-19 vaccines authorised in New Zealand?  

All medicines approved for use in New Zealand, including vaccines, go through strict review by Medsafe to make sure they meet local and international safety and efficacy guidelines. Once Medsafe has reviewed all available data, it will make a recommendation to the NZ Government as to whether a medicine can be granted approval in NZ. More comprehensive information on this process is available on the Medsafe website

The first vaccinations against COVID-19 have already begun using the mRNA COVID-19 vaccine, Comirnaty™ (from Pfizer/BioNTech). It is currently being given to those at highest risk of exposure to SARS-CoV-2, the virus that causes COVID-19. The exact date when other vaccines will be available in New Zealand is unknown. Their arrival depends on: 

  • Data being available to review, particularly in relation to safety and effectiveness  

  • When Medsafe approval is granted 

  • When the vaccine can arrive in New Zealand.  

  • To obtain approval for use in New Zealand, each vaccine needs to meet strictly defined safety and efficacy criteria. 

The mRNA COVID-19 vaccine by Pfizer/BioNTech was granted provisional approval for use in New Zealand on 3 February 2021. This means that it has been approved for use in a defined group and on the condition that Medsafe continues to receive and review further data about this vaccine’s safety and effectiveness. Click here to find out more. 

This approval differs from that granted in other countries, such as the US, UK and in Europe, in which these vaccines were granted ‘emergency-use approval’ based on early data and an urgent need to start vaccinating soon as safely possible. New Zealand has been fortunate to be able to wait, while receiving the most current clinical trial and post-licensure data, to make the decision to approve the use of this vaccine. Once sufficient data has been obtained, it is likely that Medsafe will convert the provisional consent to full consent in due course. 

Watch this video from the Ministry of Health with Dr Ashley Bloomfield and MedSafe's Chris James for more on the vaccine approval process in New Zealand.  

What are the ingredients of COVID-19 vaccines? 

Vaccine ingredients depend on the type of vaccine. As vaccines are approved for use, the contents and presentation of each vaccine is published by Medsafe as a data sheet and consumer medicine information. These form part of the information that companies submit during the approval process. See below vaccine ingredients from two vaccine candidates which are being used in COVID-19 vaccination programmes internationally. 

Some types of vaccines use human cell lines in the vaccine manufacturing process. This is known to be a safe and efficient way to produce vaccines. Both the Janssen and Oxford/AstraZeneca COVID-19 vaccine candidates use cell lines. NO cells from the manufacturing process remain in the vaccine because purification removes all the cell culture material and each batch undergoes thorough quality control checks. The Catholic Church has issued a formal statement saying it is morally acceptable to take vaccines that use cell lines.. Find further information on fetal cells and COVID19 vaccines here. 


Ingredients of the Comirnaty™ COVID-19 vaccine, manufactured by Pfizer/BioNTech (as given in Medsafe CMI and data sheet)

  • Active ingredient: 30µg of a nucleoside modified messenger RNA (BNT162b2) encoding the viral spike (S) glycoprotein of SARS-CoV-2embedded in a lipid nanoparticle

  • Fats (these ingredients make up the lipid nanoparticle which is the transport mechanism for the active ingredient to make it inside a cell without being broken down) 

    • 0.43 mg (4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate) 
    • 0.05 mg 2[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide 
    • 0.09 mg 1,2-distearoyl-sn-glycero-3- phosphocholine 
    • 0.2 mg cholesterol 
  • Salts (these ingredients help ensure the vaccine pH is close to that of human cells) 

    • 0.01 mg potassium chloride 
    • 0.01 mg monobasic potassium phosphate 
    • 0.36 mg sodium chloride 
    • 0.07 mg dibasic sodium phosphate dihydrate 
  • Sugar (this ingredient protects the lipid nanoparticle at the very cold temperatures [around -80ºC] that the vaccine is stored at) 

    • 6mg sucrose 



Last updated: Mar 2021