What do we know about the Novavax and Pfizer COVID vaccines...

These two vaccines complement the vaccine supply agreements announced in September by the University of Oxford / AstraZeneca and the University of Queensland / CSL. Australia will also have access to vaccines through the World Health Organization-supported COVAX initiative.

However, these precautions depend on whether the vaccines have been shown to be safe and effective in ongoing clinical trials. What do we know about the two vaccines in this last deal?

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What do we know about the Novavax vaccine?

The Novavax vaccine NVX-CoV2373 contains purified pieces of the spike protein from SARS-CoV-2, the virus that causes COVID-19.

These proteins are given an adjuvant, a molecule that increases the immune response. The idea is that when this vaccine is administered, the body will recognize its contents as “foreign” and trigger a protective immune response.

Early clinical studies were conducted in Australia. In the phase 1 clinical trials, the vaccine was generally well tolerated and produced strong antibody responses that were stronger than in patients who recovered from COVID-19.

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In September, Novavax started a phase 3 clinical trial in the UK. Further large-scale clinical studies are planned for other countries in late 2020 and early 2021.

If the Novavax vaccine is successful, 40 million doses are expected to be available in Australia in 2021, with the option to purchase an additional 10 million.

What do we know about the Pfizer vaccine?

The BNT162b2 vaccine developed by Pfizer is based on the genetic material mRNA (or messenger ribonucleic acid). Such mRNA vaccines carry a piece of genetic material that codes for viral proteins or parts thereof. Once your mRNA is in your cells, it instructs your cells’ protein factories to make copies of these viral proteins. These then stimulate your immune system to build a protective immune response.

Pfizer’s BNT162b2 vaccine encodes the full-length spike protein of the virus.

In early clinical trials, the vaccine was generally safe with no serious side effects. The vaccine produced a robust immune response even after two doses.

When older adults (65-85 years old) were vaccinated, they showed a stronger neutralizing antibody response than in patients who became naturally infected with SARS-CoV-2.

Interestingly, BNT162b2 is one of the first COVID-19 vaccines to be tested in teenagers (12-18 years old).

In July, Pfizer announced the start of large-scale phase 2/3 trials. Trials with 44,000 participants are underway in several countries, including the USA, Germany, Argentina, Brazil and South Africa.

One of the challenges for this vaccine is distribution as it must be stored below -70 ° C. This is costly and makes transportation difficult, especially in developing regions.

If BNT162b2 is successful, 10 million doses will be available in Australia by early 2021.

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What happens next?

Both vaccines, when successful in clinical trials, will be manufactured outside of Australia.

This will allay fears that Australia may no longer receive mRNA vaccines as the country does not have the technology and capacity to manufacture these vaccines on its own.

A successful COVID-19 vaccine must also go through the Therapeutic Goods Administration’s rigorous evaluation and approval processes for use in Australia.

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Securing our bets

It is unlikely that all of the COVID-19 vaccines currently in development will be successful. We have already seen COVID-19 vaccine trials being temporarily stopped for safety reasons. And not all vaccines offer a consistent level of immunity. Some vaccines may only offer immunity for limited periods of time and require a booster shot.

By investing in numerous top candidates, the Australian government’s strategy of not putting all your eggs in one basket makes sense.

Investing in a range of vaccine technologies also has benefits in the event that more than one vaccine becomes available. This is because different vaccine technologies can be more effective or safer in different populations. This increases the likelihood that all parts of society – young and old, with or without existing medical complications – can be targeted.