ATAGI updates post-infection vaccination advice

The Australian Technical Advisory Group on Immunisation (ATAGI) is now advising a three-month wait after confirmed SARS-CoV-2 infection before a further COVID-19 vaccine dose is administered, including for booster and winter doses.
 
The advisory group recommends the next scheduled dose be given as soon as possible after three months has elapsed.
 
Its advice comes with COVID-19 infections expected to rise in the coming winter season, and many people having already been infected in the community.
 
Speaking in a recent Department of Health (DoH) primary care COVID-19 webinar, Deputy Chief Medical Officer Professor Michael Kidd said that of the estimated 5.6 million Australian cases in total since the start of the pandemic, more than 5.2 million have been since the start of 2022.
 
Dr Lucas de Toca, DoH First Assistant Secretary, said that previous recommended timings between doses and infections had been ‘somewhat confusing’ and that the previous recommendation was ‘in the context of Delta versus Omicron’.
 
Previously ATAGI recommended patients should receive their first booster shot as soon as they had recovered from a COVID-19 infection, while those eligible for a further winter dose – such as people aged 65 and older – were advised to wait at least four months after infection.
 
The three-month recommendation means the waiting time is consistent in all cases.
 
The wait is intended to optimise protection, ATAGI states, with the longer gap ‘likely to lead’ to a better immune response and reduce the risk of reinfection for longer.
 
Dose intervals
ATAGI also changed advice for the primary COVID-19 vaccination course for the mRNA vaccines and now recommends an eight-week gap between first and second doses . 
 
However, with most of the population now vaccinated, this will affect very few people in Australia.
 
This supersedes previous advice of dose intervals for the mRNA COVID-19 vaccines of 3–6 weeks for Pfizer and 4–6 weeks for Moderna. 
 
‘The extended dose interval of eight weeks has been shown to improve the immune response to vaccination and therefore may improve effectiveness,’ ATAGI states.
 
The advisory group also notes the benefits of longer dose intervals potentially reducing the risk of myocarditis and pericarditis, aligning with World Health Organization recommendations based on an observed higher vaccine effectiveness and reduced risk of myocarditis and/or pericarditis with a longer interval.
 
A preprint study from Canada also found that for both Pfizer and Moderna, a higher rate of myocarditis and/or pericarditis was observed in people 12 years and older when the interval between dose one and two was 30 days or less.
 
When compared to an interval of 56 days or more, those who received dose two 30 days or less after dose one were around three times more likely to develop myocarditis and/or pericarditis. This risk was also greater when receiving Pfizer followed by Moderna at a 30-days-or-less interval.
 
The risk of myocarditis and pericarditis following the Novavax vaccine is currently unknown.
 
ATAGI particularly recommends the longer dose interval for people under the age of 40 who are at higher risk of developing myocarditis and/or pericarditis as a vaccine side effect.
 
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ATAGI boosters COVID-19 vaccine intervals