Study examines whether RSV vaccine lasts ‘at least three winters’

A single dose of a respiratory syncytial virus (RSV) vaccine widely available in Australia offers protection against the disease to older adults for three seasons but decreases in efficacy over time, according to the results of a large-scale study.
 
Research looking at the efficacy of RSVPreF3 OA (sold as Arexvy) was published this month in The Lancet Respiratory Medicine journal.
 
The authors said the duration of protection from vaccination is unknown, with the study aiming to assess the vaccine’s efficacy and safety over three seasons.
 
The randomised controlled trial, which was funded by Arexvy manufacturer GSK, included 12,468 vaccine recipients and 12,498 who received a placebo.
 
The participants from across 17 countries in Africa, Asia, Oceania, Europe, and North America were enrolled between 25 May 2021 and 31 January 2022.
 
They were randomly assigned to receive either the vaccine or placebo for season one, then randomly re-assigned to receive either the vaccine or placebo in season two.
 
Serious adverse events were recorded in eight participants in the RSV single-dose group, 12 in the RSV revaccination group, and 12 in the placebo group. The article also notes that five deaths were related to the trial intervention, including three in the vaccine groups.
 
They concluded that a single dose was effective over three RSV seasons in people aged 60 years or older ‘despite a decrease in efficacy over time’.
 
Authors also noted that ‘further research is needed to establish the optimal revaccination strategy’.
 
According to the Immunisation Handbook published by the Department of Health and Aged Care, a single dose of RSV vaccine is recommended to protect people aged over 75.
 
It says the RSV vaccine may be given at any time of the year but is ideally offered before the start of the RSV season.
 
The two vaccines registered for use in adults aged 60 and above in Australia are Abrysvo and Arexvy, with the latter approved by the Therapeutic Goods Administration last year.
 
Vaccination is also recommended for those at greater risk of severe RSV disease aged over 60.
 
The Immunisation Handbook says there is ‘no brand preference for this age group’ and also notes that the ‘need for further doses has not yet been established’.
 
At the opposite end of the age spectrum, an ongoing program for nirsevimab (sold as Beyfortus) has also now been started in every Australian state and territory, offering a long-acting monoclonal antibody for infants who have not already received a maternal vaccine.
 
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respiratory viruses RSV vaccine