On Sunday, federal Chief Medical Officer Professor Paul Kelly stated most Australians might be supplied a vaccine from Oxford-AstraZeneca.
Australia at present has agreements in place to obtain 53.8 million doses of the AstraZeneca shot, and 10 million doses from Pfizer-BioNTech.
So how do these two vaccines evaluate, how will they be utilized in Australia, and what can we be taught from different vaccines?
Evaluating the 2
Each the Pfizer and AstraZeneca vaccines induce immunity however in numerous methods. They each ship the directions for methods to make a goal on the virus for our immune system to recognise the spike protein.
The Pfizer vaccine packages the directions up in a droplet of fats, whereas the AstraZeneca vaccine packages the directions up within the shell of a virus, the adenovirus.
Medical trials for each vaccines have proven they’re broadly secure.
By way of efficacy, the Pfizer vaccine protects 94.5% of individuals from creating COVID.
The AstraZeneca shot protects 70% of individuals on common — nonetheless fairly good and on par with the safety given by a flu vaccine in a great yr.
Nevertheless, the optimum dose and timing of AstraZeneca’s pictures remains to be unclear. One trial reported 62% efficacy, and one other 90%, with a low dose for the primary shot and/or longer break between doses presumably enhancing safety. Extra research are underway to outline this and the Therapeutic Items Administration, Australia’s regulatory physique, will consider new knowledge because it comes by way of.
In any state of affairs, the AstraZeneca vaccine will nonetheless defend nearly all of those who obtain the vaccine from illness.
Whereas the Pfizer vaccine was extra protecting in medical trials, the AstraZeneca vaccine has different benefits that would make it extra applicable to be used exterior of medical trials:
From a logistical perspective, the AstraZeneca vaccine has a serious benefit. The power to distribute vaccines might be virtually as necessary because the vaccine’s effectiveness.
The impact of those benefits on the affect of this vaccine shouldn’t be underestimated. We now have a number of individuals to vaccinate, a low illness burden at present, are distant from the remainder of the world by way of delivery, and Australia is a fairly large nation, so distribution to rural and distant communities is a large hurdle.
Efficacy isn’t the one factor we must always take into account
It may be useful to have a look at the flu vaccine as a distinction. The flu vaccine is way from good — it offers average safety, with effectiveness various between totally different teams of individuals and from season to season. For instance, within the 2015/16 season in america, the quadrivalent influenza vaccine (which covers 4 strains) was about 54% efficient in opposition to laboratory-confirmed influenza.
Folks realize it’s not good, however individuals don’t usually decide whether or not they’ll obtain a vaccine primarily based on its effectiveness alone. We all know from speaking to the neighborhood that many components affect motivation, particularly perceived danger and severity of an infection, and confidence within the security of the vaccine.
Yearly, entry to flu vaccines is prioritised to these at most danger, corresponding to individuals with medical situations, Aboriginal and Torres Strait Islanders and people aged 65 years and older. The general public has confidence on this method. We have to defend these most at-risk first, and we don’t have a problem doing this day-to-day. We now have an analogous problem with the brand new COVID vaccines.
The perfect method for shielding everybody’s well being amid the pandemic is to supply totally different vaccines to totally different individuals in accordance with want and availability, at the very least within the brief time period. The perfect vaccine is all the time the one you will get to the communities that want it earlier than they urgently want it.
Australia’s mixture technique
As a result of Australia is actually COVID-free at current, it means we’re in a novel scenario that allows a “mixture” vaccine technique.
The Pfizer vaccine is ideal for stopping essentially the most excessive outcomes for individuals at very excessive danger of an infection or illness: individuals on the frontlines of the struggle in opposition to COVID and older individuals or individuals with high-risk well being situations.
The AstraZeneca vaccine has the power to guard numerous individuals in opposition to illness shortly, as a result of we will make it simply and distribute it shortly.
Because of this, Pfizer is prone to be prioritised for individuals with greater danger and AstraZeneca is prone to be prioritised for everybody else.
We received’t all be capable to get the Pfizer vaccine right away, so for many people the selection within the brief time period might be between a 70% efficacious vaccine or no vaccine.
All of us stand to learn from a method that protects extraordinarily susceptible teams from extreme illness and goals to quickly generate immunity in the remainder of our neighborhood.
There may additionally be different vaccines that turn out to be accessible. Australia is a part of COVAX which may distribute quite a lot of vaccines, and it additionally has an settlement for a vaccine made by Novavax, pending the result of section 3 medical trials. There could possibly be different vaccines that emerge or different agreements developed, and Australia’s technique will little question reply to that.
Nonetheless, each the Pfizer and AstraZeneca vaccines are important instruments in our public well being toolkit, with very important roles to play in defending the complete Australian inhabitants. We’ll additionally have to proceed to make use of different public well being instruments like testing and make contact with tracing.
Factoring in effectiveness, availability and distribution challenges, a method that makes use of a mixture of the 2 vaccines for Australia is one of the best of each worlds.
Shane Huntington additionally contributed to this text. He’s Deputy Director, Technique and Partnerships, College of Drugs, Dentistry and Well being Sciences, College of Melbourne.