Australian Chief Medical Officer Professor Paul Kelly and infectious disease experts have defended getting 54 million doses of a Covid-19 vaccine made by the University of Oxford and pharmaceutical company AstraZeneca, amid fears that the vaccine may not be effective enough to achieve collective immunity.
The president of the Australian and New Zealand Society for Immunology, Professor Stephen Turner, told Nine media that Australia should halt the rollout of the AstraZeneca vaccine because it has “lower efficacy”.
“You cannot rely on it to establish collective immunity,” he said.
The chief of the Western Australian section of the Australian Medical Association, Dr Andrew Miller, who is an anesthesiologist, echoed the comments to the Australian, saying: ‘We need to pause and consider what the results will be before. to take next steps. “
Interim results from the Oxford / AstraZeneca Covid-19 vaccine trials have shown that the vaccine protects against symptomatic disease in 70% of cases, with vaccine efficacy of 62% for those who received two full doses and 90% for those who have. received half and then a full dose.
Kelly said on Wednesday that the AstraZeneca vaccine was effective, safe and of high quality.
“It’s very effective against serious illnesses,” Kelly said. “It will save lives. By using this vaccine, we will be able to protect a large part of the Australian population. He said Australia had also obtained doses of other candidate vaccines, including the Pfizer vaccine.
The Pfizer vaccine is a new type of vaccine, containing strands of genetic material called mRNA. When this enters the body’s cells, it asks them to make a piece of the “spike” protein which is unique to the virus. These harmless pieces of protein trigger an immune system response, so if they get infected with the real virus, the body will know how to attack.
The University of Oxford / AstraZeneca vaccine is a viral vector vaccine, containing a weak or inactivated virus that cannot cause disease. This virus contains genetic material of the inserted Covid-19 virus. Once the viral vector is inside human cells, the cells make a protein unique to the Covid-19 virus. This triggers the body to start building an immune response.
One of the advantages of the AstraZeneca vaccine is that it can be made in Australia, while the technology for mass production and cold chain storage of new mRNA vaccines is not available in Australia. Fifty-one million doses of the Novavax protein vaccine have also been secured, and Australia has joined the Covax Facility, which will purchase more doses of vaccine and other vaccines as they become available.
“These are all very good vaccines in terms of efficacy for symptomatic illnesses,” Kelly said.
“All three vaccines that have so far published their data in peer-reviewed journals, namely AstraZeneca, Pfizer and Moderna, all show a very significant effect against serious disease.
He said: “We have several eggs in the basket,” adding that the US, UK and others have also obtained millions of doses of the AstraZeneca vaccine. Australia was not forced to choose one vaccine over another, he said.
“We’ve had so few cases in Australia that we’re completely unimmunized,” Kelly said. “The choice is not whether one is better than the other, it’s the one that is available to give the maximum amount of vaccines to save lives and protect lives this year. And the answer to that is what we can provide here. We don’t have the capacity to make an mRNA vaccine on land. “
Guardian Australia understands that the Federal Government will be holding briefings within the next 24 hours with various stakeholders, healthcare professionals and researchers to explain the science behind Australia’s various vaccine candidates and to dispel any misinformation.
Professor Lyn Gilbert, chair of the Infection Control Panel, which provides independent, evidence-based advice to the federal government, said comments calling for a halt to AstraZeneca deployment were “misguided” .
“It is based on too little information on the effectiveness and duration of protection, or on the ability of any of the vaccines to prevent transmission; an assumption that there will be unlimited availability of what are considered to be the most effective vaccines which are currently mRNA vaccines such as the Pfizer vaccine, to everyone; and an unrealistic expectation that elimination of the virus is possible, ”Gilbert said.
Professor of infectious diseases and former World Health Organization adviser Peter Collignon called calls to stop the delivery of AstraZeneca as “mania”.
“If you look at Melbourne, if all of these people in nursing homes had been vaccinated with this AstraZeneca vaccine before this second wave, it would have saved about two-thirds of deaths,” he said. “It’s not perfect, I would like to have 90% or 100% efficiency. But with the first batch of vaccines, the dosing regimen may not always be optimally organized, and this will show after its wider deployment. “
He said some of the people calling for his shutdown were the same people or groups “who said three weeks ago, ‘Don’t delay deployment to Australia, deploy now.’ I think it went from one extreme to the other. ”
The Federal President of the Australian Medical Association, Dr Omar Khorshid, distanced himself from the comments of his WA counterpart. Khorshid said if the government could invest in other types of vaccines in addition to the three already guaranteed, it was too early to know whether any of the vaccines would stop the transmission of the virus as well as the serious illness.
“The government made deals with a number of companies long before there was any data on whether their vaccines were ever going to be made,” he said.
“And so far two of them appear to be available in Australia, and there are potentially more to come. And we don’t know which vaccine will be best for which different parts of the population, and that’s all data we’re going to learn more about over time.
Australia’s Immunization Technical Advisory Group co-chair Professor Allen Cheng said it was important to remember that the AstraZeneca vaccine has yet to be registered by Australia’s drug regulator, the Therapeutic Goods Administration. The Pfizer vaccine either.
“I think we are in a privileged position where we can be careful,” he said.
“Australia currently has access to 10 million doses of Pfizer vaccine to be administered over one year and 53 million doses of AstraZeneca vaccine to be administered approximately one million doses per week. We do not know to what extent they reduce transmission. The AstraZeneca vaccine did not reduce asymptomatic infection, and this was not examined in the Pfizer vaccine study.
“Even if the Pfizer vaccine were fully effective against transmission, covering 20% of the population over a year would be unlikely to achieve herd immunity. So the choice we have is not to use one or the other, but to use what we have – I think there is a benefit in protecting against disease, even if that does not reduce the transmission to the degree that we would like.