Vaccines will not prevent infection by Covid

Professor John Shine - Covid vaccines will be safe and effective. Photo / supplied

Australian Academy of Science president Professor John Shine last week addressed "significant misunderstandings" and differing views regarding the effectiveness of first-generation Covid-19 vaccines.

"It is crucial that the distinction be made between a vaccine's effectiveness at protecting from severe disease versus its effectiveness at stopping transmission," he said.

Australia's current vaccination strategy was aimed at reducing the severity of disease – "Put simply, to reduce the number of exposed individuals getting very sick or dying." Those who were vaccinated would be protected from the worst of Covid-19, but would not be protected from becoming infected.

None of the vaccines that had been approved for use had demonstrated that they could stop transmission of SARS-CoV-2, with no conclusive data available as yet.

Australians could be confident that vaccines approved for use by the Therapeutical Goods Administration would be safe and effective at reducing the risk of developing severe Covid-19, however.

"Australia has become a pandemic success story," Shine added.

"The majority of individual Australians' willingness to follow public health directions, and a laudable commitment from governments to listen to experts and allow science to guide policy, has been mostly responsible for this success.

"Australia is in a fortunate position, as we are not facing the Covid-19 transmission rates currently experienced by the USA, the UK, European countries and others worldwide. Our hospitals are not operating at capacity, and death and community transmission rates of Covid-19 are low. We are not experiencing conditions that would require vaccination roll-out via emergency use authorisation. As such, our nation will benefit from growing data on vaccine dose and effectiveness as they are implemented in countries with the greatest need."

In terms of preventing infection to the point requiring hospitalisation, the AstraZeneca and Pfizer vaccines were equally effective, but public confusion had arisen around the implications of 62 per cent or 95 per cent effectiveness of first-generation Covid-19 vaccines in terms of protecting against the development of mild to moderate Covid-19 symptoms.

"Either vaccine is amply effective to prevent severe disease, the outcome we all fear most and the primary goal of Australia's vaccination strategy," he said.

"The approval and deployment of Covid-19 vaccines alone will not bring an end to the pandemic. Consequently, public health measures such as practising good hygiene, high levels of testing, contact tracing and physical distancing must continue in 2021.

Australians should get vaccinated," he added.

"Administering first-generation vaccines will be critical to reducing the number of people infected with Covid-19 who then progress to hospitalisation, intensive care or death. It will allow us to avoid a major wave of illness like that currently being experienced in the Northern Hemisphere.

"Lifting public health measures will only be possible following further research, adequate worldwide vaccination and the control of spread at an international level. In this context, the Australian government's commitment to the World Health Organisation, COVAX and supporting our Pacific and South-East Asian neighbours to obtain access to vaccines is highly commendable.

"Australians can be reassured that the current Australian government vaccination strategy is informed by experts and the best available science. Only science will solve this."