Analysis: Aaguide to the vaccine which many claim will be a gamechanger in the fight against Covid-19
With the Johnson & Johnson (J&J) vaccine receiving emergency use authorisation in the United States, It shouldn’t be long until Europe follows suit. Now is a good time to have a look at this candidate and how it compares to the already approved Pfizer/BioNTech, AstraZeneca and Moderna vaccines. This would potentially be the fourth vaccine to receive approval for use within Ireland.
200 million J&J vaccines have been promised before the end of March to the EU and Ireland is set to receive 2.2 million doses. This raises such questions as who should receive which vaccine and what makes it different from the other vaccines.
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From RTÉ Radio 1's Morning Ireland, Dr Leisha Daly from Johnson & Johnson on the company's development of a one-dose Covid-19 vaccine
How does this vaccine work?
The J&J's mechanism of action is different from the previously discussed Pfizer/BioNTech mRNA vaccine. In this instance, a common cold virus (adenovirus 26), which has been altered so that it can’t replicate in the body to cause disease, acts as a shuttle to deliver instructions for making the coronavirus’s spike protein to human cells. These cells then synthesise the spike protein which triggers an immune response to produce antibodies and also activate cellular immune defences from T-cells, which attack the coronavirus should it return at a later date. This system of an adenovirus shuttle was used by J&J for the Ebola vaccine and experimental vaccines against Zika and HIV. Both the AstraZeneca and Russia’s Sputnik V vaccines also use the same technology.
Is it better than the vaccines we currently have?
The J&J vaccine initially received some negative press due to a result of 66% efficacy at preventing "moderate to severe" disease. When you compare that to the 95% efficacy of the mRNA vaccines (Pfizer/BioNTech and Moderna), you would be forgiven for having a preference to receive one of these vaccines.
But making cross-trial comparisons like this has its pitfalls. The coronavirus landscape has significantly changed due to the expected emergence of variants. The early excellent results from Moderna and Pfizer/BioNTech mRNA vaccines were achieved before the emergence of these variants. J&J has developed an excellent vaccine and headline efficacies are not a fair comparison, as part of the testing was carried out in South Africa and Brazil where some worrisome variants of the virus were first seen.
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RTÉ News graphic showing approved vaccine rollout to date
The most important metric of a vaccine's efficacy is its ability to prevent hospitalisations and death. The J&J vaccine is just as effective as its Astra Zeneca, Moderna and Pfizer/BioNTech counterparts at preventing those. Not one individual in the phase 3 vaccine study (10,000 participants) was hospitalised or died due to Covid-19 once recipients were 28 days out from their vaccination. In the context of a pandemic that has claimed 4,313 lives in Ireland and 2.53 million globally, this is crucial. Our main goal is to save lives and to stop serious illness and death from Covid-19.
What are the advantages of the J&J vaccine?
The J&J vaccine is given as a single shot instead of two, therefore twice as many people can be vaccinated with the same number of doses. It only needs to be refrigerated, not frozen, making widespread availability much easier.
It remains stable for at least three months at normal refrigeration temperatures, which eases some of the time constraints and logistical problems with vaccine rollout that the world is facing. This gives unparalleled expediency for vaccine-recipients and health-care professionals while still maintaining impressive efficacy against the most serious forms of the disease. In terms of side effects, there is good news on that front also, milder side effects than already authorised Astra Zeneca, Moderna and Pfizer/BioNTech vaccines have been reported.
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From RTÉ One's Nine News, a new Israeli study shows Pfizer vaccine is 94% effective
How does the J&J vaccine compare to its brothers in arms?
Like the other vaccines, it is almost 100% effective against hospitalisation and death. It is delivered as a single shot and can be stored in a standard clinical refrigerator. We have scant evidence on its ability to reduce transmission because it hasn't been used on a wide enough scale but initial studies are promising. There’s a higher chance versus the Pfizer or Moderna vaccines that you may get some symptoms if you become infected, but these symptoms are likely to be mild and the vaccine itself has fewer (mild) side effects.
Is this good news for Ireland?
If the J&J vaccine is authorised in the coming weeks by the European Medicines Agency (a decision is expected on March 11th), and our allocated number of vaccines arrive, Ireland must be ready to ensure its effective distribution. The goal must be to get as many people fully vaccinated as quickly as possible.
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From RTÉ News, over 500,000 vaccines have been administered to the end of February in Northern Ireland
This single shot vaccine represents a unique opportunity to distribute it to areas with higher concentrations of people who might be less likely to return for a second dose and to rural and remote areas lacking cold chain storage capabilities. We need a strategy in place to ensure the benefits of this single-shot vaccine are known and communicated properly to communities where convenience could potentially trump the decision to not get vaccinated at all.
We need to educate every Irish person about the true efficacy and safety of this new vaccine. Yes, it prevents most infections but, more importantly, the worst symptoms will be mitigated should you get Covid-19 once vaccinated.
Which vaccine is best for you and your loved ones?
The first one which you are offered! This strategy presents everyone individually and collectively the best chance of getting to the other side of this pandemic and seeing each other again safely.
The views expressed here are those of the author and do not represent or reflect the views of RTÉ
