There are 53.8 million doses of the AstraZeneca vaccine on order. It, too, requires two injections per person, given several weeks apart.

A headline from The Australian sums up the panic: ‘‘Vaccine ‘not good enough to stop the coronavirus’.’’

Is it true? The fact is, we don’t know for sure how well the AstraZeneca vaccine works.

The complaints from doctor groups is based on data from an interim report published in The Lancet in early December.

The researchers concluded the vaccine was “safe and efficacious … if deployed with high coverage.”

But, as The New Daily reported, the numbers were tricky.

Oxford/AstraZeneca claimed to have produced a vaccine with an efficacy of up to 90 per cent. Better still, it could be had “for the price of a cup of coffee”.

Then it was revealed that the overall efficacy of the vaccine was 70.4 per cent. So … what did these numbers mean?

In effect, there were three trials. Two groups – one in the UK, one in Brazil – were given two standard doses, a month apart, with OK results.

The UK trial had an estimated 60.3 per cent efficacy; the Brazil trial had an estimated efficacy of 64.2 per cent. Averaged out, the combined efficacy was 62.1 per cent.

In a third trial of about 3000 people in the UK, participants were accidentally given a half-strength dose in the first injection.

When it became clear that side effects such fatigue and headaches were milder than expected, the mistake was revealed.

On the upside, when the participants received the second full-strength injection, 90 per cent of the group were protected against the virus. However, none of the participants were older than 55.

The problems remaining are these: The extent to which the vaccine reliably works, especially in older people, remains unclear; the range of efficacy data from three trials is significant; and the manner in which the company managed disclosure of a mistake in one of the trials has led to a feeling the company can’t be entirely trusted.

At the time, The New Daily concluded: “… with the company having seriously muddied the water in the meantime, Australians deserve a clearer understanding of the vaccine’s reliability before proceeding taking it in the arm en masse.”

A month after this mess became apparent, Australian doctors have seized upon that 62.1 per cent efficacy rate to claim the government has bet the farm on the wrong horse – and we should buy up the Pfizer or Moderna jab instead.

Except we can’t for reasons outlined above.

Canada just doubled its order of the Pfizer mRNA vaccine from 20M to 40M doses. Why can’t Australia also negotiate increased supply of high-efficacy #COVID19 vaccines? https://t.co/pRuQBnRm28

— Benjamin Veness 😷 (@venessb) January 13, 2021

What a pickle.  Could AstraZeneca  redeem itself?

According to Melissa Millard, a spokeswoman from AstraZeneca, there are are four issues to keep in mind:

1. Trials are continuing to establish the optimum dose. It may be that, as found in the accidental discovery, that a half dose reliably facilitates a 90 per cent efficacy rate. Further trials on dosage could possibly improve that result
2. A fuller data set than that found in the Lancet interim report has been submitted to the TGA. It’s not yet publicly available. And more data is being continually generated
3. Any approval from the TGA will be provisional, as it will be for the Pfizer vaccine, “because it’s based on an extraordinary set of circumstances”
4. Second and third-generation vaccines are expected to eventually replace those being deployed this year.

People in the UK are already receiving the AstraZeneca vaccine, which is being described as “central to the government’s plans for ending social distancing in the UK and returning to some sort of normality”.

The UK has “invested in seven different vaccines, but the biggest order is for 100 million doses of the AstraZeneca jab, most of which will be manufactured in the UK”.

The World Health Organisation has optioned up to 900 million doses.

Is there another option?

Australia has ordered 51 million doses of the dark-horse Novavax vaccine.

The company is a small, innovative vaccine maker based in Maryland that has never brought a vaccine to market.

When the pandemic took hold, it quickly emerged with a vaccine made from moth cells that appeared to knock out the the coronavirus spike protein.

It reportedly “outshone major competitors on key measures in monkey and early human tests”.

Novavax twice delayed its Phase III trial that is meant to prove efficacy on a big scale. The company began enrolling participants in late December. Interim results are said to become available in the first half of 2021.

Meanwhile, some hard data is to become available from a Phase IIb trial in the next fortnight.

One problem: It relies on contract manufacturers to meet its target of a billion doses.

As The New Daily reported on Thursday, CSL – the Australian company manufacturing the AstraZeneca vaccine for local use – could possibly end up manufacturing the Novovax vaccine. But it can’t make both at the same time.

For the moment then, AstraZeneca – with all its unknowns – is pretty much our only option to protect most of the population from becoming seriously ill. Which it appears to do.

On Thursday night, a statement from the Australian Academy of Science said:

“In preventing severe COVID-19 that requires hospitalisation, both the AstraZeneca and Pfizer vaccines are equally effective.

“Accordingly, the Academy supports the current Australian Government vaccination strategy, informed by the best available expertise and science.”