'EMA will assess the vaccine's safety & efficacy.
Switzerland approved the Moderna vaccine on Tuesday and plans to immunize about 4% of its population using that and the Pfizer-BioNTech shot.
"Some of the correspondence has been manipulated by the perpetrators prior to publication in a way which could undermine trust in vaccines", the Netherlands-based agency said.
Pollard said that the impact of a vaccine could only be determined "when they're in people's arms".
It comes as the government races to strike new COVID-19 vaccine deals as it stares down criticism of the effectiveness of the AstraZeneca jab.
"However, the effectiveness of a vaccine [capable of creating herd immunity] must be at least 70 or 80%", said an expert of the Society for Infectious Diseases, a researcher at the University.
An 82-year-old man became the first person in the world to receive the Oxford-AstraZeneca jab as the United Kingdom rolled out the vaccine as part of its inoculation program earlier this month.
A scientist who led the development of the Oxford-AstraZeneca COVID-19 vaccine has warned Australia against delaying its rollout. German media has reported similar findings.
The AstraZeneca vaccine has the major advantages of being both easier to store than others and relatively low-priced, costing about 2.75 euros ($3.40) per dose.
The agency did not explain exactly what information was altered - but cybersecurity experts say such practices are typical of disinformation campaigns launched by governments. He proposed to suspend the planned rollout of vaccinations with AstraZeneca and purchase more effective ones.
"The great advantage of the AstraZeneca vaccine is it's being made here in Australia", Kelly said.
The team believes that Australia has managed well in controlling the spread of the pandemic.
Its success is largely attributable to closed borders and widespread compliance with social-distancing rules, along with aggressive testing and tracing programmes.
The Oxford-AstraZeneca vaccine is expected to be a key vaccine for many countries because of its low cost, availability and ease of use.
Australia recorded one new local coronavirus case in its most populous state of New South Wales on Wednesday.
In Queensland, hundreds of hotel quarantine guests were forced to restart their isolation after a handful of cases in the facility were linked to the highly contagious United Kingdom virus strain.