ATAGI reveals how quickly Covid-19 vaccine effectiveness can wane from second dose

The effectiveness of Covid vaccines can drop from 80 per cent to zero in just four months, the Australian Technical Advisory Group on Immunisation (ATAGI) has warned. 

The alarming decrease in effectiveness in both the Pfizer or AstraZeneca vaccines, has triggered ATAGI to recommend booster shots after just three months, as Omicron continues to ravage Australia. 

New advice from the Immunisation body shows initial protection of 36 per cent to 88 per cent is estimated to wane rapidly to 0 to 34 per cent approximately four months out from the second dose.

This means a person who has received both doses could lose up to 50 per cent protection against Covid in just 120 days. 

Vaccine effectiveness against the risk of hospitalisation with Omicron was also found to drop, falling to 52 per cent.

ATAGI said a Pfizer booster shot appears to restore ‘moderate levels’ of effectiveness against symptomatic Omicron cases by 71 to 76 per cent.  

A booster dose was also found to increase vaccine effectiveness against hospitalisation to 88 per cent.  

‘Receipt of a primary schedule and a booster dose will provide individual protection from infection and hospitalisation with the Omicron variant, although these effects will wane,’ ATAGI said in a statement. 

‘It is known that protection against onward transmission also wanes over several months after completing the primary series for the Delta variant. This may be similar with the Omicron variant.

A person who has received both doses of AstraZeneca and Pfizer could lose up to 50 per cent protection against Covid-19 in just 120 days (pictured, Sydney-siders enjoy the hot weather in December)

‘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.’ 

On Thursday, the Federal Government updated its vaccine policy based on new advice from the national drug regulator. 

Under the new policy Australians will no longer be classed as ‘up to date’ on their Covid vaccinations if they have not had a booster six months after their second jab.

While National Cabinet stopped short of mandating a third job for those in essential roles, aged care workers will be required to get a booster dose or face the sack.  

Australians will no longer be classed as ‘up to date’ on their Covid vaccinations if they have not had a booster six months after their second jab (pictured, a resident receives their Covid-19 vaccine at a Sydney clinic in September)

‘Under the new advice, a person is ‘up to date’ if they have completed all the doses recommended for their age and individual health needs,’ Health Minister Greg Hunt said.

‘ATAGI recommend that everyone aged 16 years and older receive a booster dose three months after their primary course, to maintain the best protection and an ‘up to date’ status.

‘Further, ATAGI has advised that if it has been longer than six months since a person’s primary course and they haven’t had a booster, they will no longer be considered ‘up to date’ and instead will be considered ‘overdue’.’