Health Minister Greg Hunt (Image: AAP/James Ross)

Herd immunity from COVID-19 is the long-term goal, the Australian government has confirmed — but its initial focus is to deliver protection and make vaccines available as soon as possible.

But the lower efficacy rate of AstraZeneca’s vaccine, which will be used to vaccinate the majority of Australians, has raised concerns around whether this is even possible. Trial results suggest it has an efficacy rate of 62.1% in two standard doses. Efficacy increases to 90% with a low dose followed by a standard dose.

In comparison, standard doses of Pfizer and Moderna’s mRNA vaccines have shown 95% and 94% efficacy, respectively.

Should herd immunity be the goal — and is it possible?

What is the government saying? 

None of the major vaccine candidates have been out long enough to know long-term transmission effects — that is, if people vaccinated against COVID-19 can still carry the virus and pass it onto other people. We also don’t know how long a vaccine will be effective for. 

The data we do have shows the vaccines, including AstraZeneca’s, prevent serious illness — so getting as many Australians vaccinated as possible is key.

“Herd immunity is often referred to as between 60 and 66%, but our goal is to make sure that, amongst the adult population, that we have a very, very high take-up rate,” Federal Health Minister Greg Hunt said last week. 

He added the AstraZeneca vaccine was considered a better candidate due to the issues around distributing an mRNA vaccine, like Pfizer’s and Moderna’s, which need to be stored at -70 degrees.

Is this enough?

Australia has high vaccination rates — even during the pandemic last year, vaccination rates for five-year-olds reached record highs of 94.9%. 

But the lower the efficacy of a vaccine, the more people will need to get vaccinated for it to be effective, Swinburne University’s School of Health Sciences dean Professor Bruce Thompson tells Crikey. 

Focusing on severe illness, he added, should be a priority.

“3% of people who develop the disease die, and 10 to 15% had rapidly accelerating disease,” he said. “Taking the vaccine means you don’t get severe illness, go to hospital, or are hammering at death’s door. 

“Ultimately if we can get over 60% of the population vaccinated that should make a profound difference in terms of us living with COVID.”

Whether this is enough to open Australia’s state and international borders remains to be seen.

“I think it will make a difference … The whole population will be in the same boat,” Thompson said.

Will the government make it mandatory?

The government quickly backtracked on comments made by Prime Minister Scott Morrison in August when he suggested the vaccine would be “as mandatory as you can possibly make it”.

So it will be voluntary, but just because the government isn’t mandating vaccinations, that doesn’t mean private companies won’t. Corporations can legally make vaccines a condition for working or using a service like attending an event or catching a flight. Qantas CEO Alan Joyce has already flagged that passengers travelling internationally might have to prove they have been vaccinated against COVID-19. 

Thompson stressed vaccine mandates were pretty normal.

“The flu vaccine was mandated to visit aged care homes during the height of COVID-19, and it’s normal to ask people to get vaccinated before they can see a new baby,” he said.

“We just need to normalise this vaccine too as a standard process, and we know when we don’t, it kills people.”