Current vaccines used to protect Australians from Covid-19 can wane from 80 per cent to as little as zero in just four months.
The latest advice released by the Australian Technical Advisory Group on Immunisation (ATAGI) revealed the early estimates of vaccine efficiency indicated “lower initial vaccine effectiveness” with just two doses of the Pfizer or AstraZeneca vaccine against the Omicron variant.
It means a double-dosed person could lose about 50 per cent of their protection within 120 days, according to the expert panel.
Vaccine effectiveness against hospitalisation with Omicron showed a “a similar pattern” of waning, falling to 52 per cent.
But ATAGI said there was an 88 per cent increased effectiveness against hospitalisation from a booster dose.
“There have been no safety signals of concern for an earlier booster dose given from three months after the primary series where this is used overseas,” the expert immunisation panel said in a statement.
“It is expected that a booster will increase protection against symptomatic infection and this should lead to a parallel increase in protection against transmission, therefore providing some indirect protection to the wider population.”
Under ATAGI’s latest advice, a person must have all doses recommended for their age and individual health in order to be deemed “up to date” and those who waited more than six months to get their booster shot would be classified as “overdue”.
It was also recommended that anyone aged 16 years and older receive a booster dose three months after their primary course.
