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While the high effectiveness of the third dose of mRNA vaccine in healthy adolescents against Omicron BA.1 has been reported in some studies, little is known about the immune response triggered by the third booster dose in this cohort. 

In this study, the researchers looked at the antibody immune response and the cellular immune response against wild-type and Omicron (BA.1, BA.2 and/or BA.5) variants of SARS-CoV-2 before and after a third dose of the mRNA vaccine in healthy adolescents; and compared them to healthy adults’ immune responses. 

It is the first study to compare age effects on vaccine responses and cross reactivity of vaccine responses. 

What the team found is that teenagers made higher magnitude immune responses than adults in a number of ways. 

University of Melbourne Associate Professor Sophie Valkenburg, a Laboratory Head at the Doherty Institute, says it shows teenagers certainly benefit from a third dose booster. 

“Our study established that a third dose of the mRNA vaccine in its current formulation can significantly boost antibody responses and T cell responses in adolescents,” Associate Professor Valkenburg says. 

Not only that, researchers also found that the third booster dose resulted in superior immune responses in teenagers compared to adults. 

With adolescents at a high risk of SARS-CoV-2 infection which may be associated with hospitalisations, multi-system inflammatory syndrome and long COVID, this research gives greater certainty that teenagers benefit from a third dose vaccination to keep a higher level of immunity against Omicron. 

Peer review: Signal Transduction and Targeted Therapy https://doi.org/10.1038/s41392-022-01282-7
Funding: Health and Medical Research Fund Commissioned Research on the Novel Coronavirus Disease (COVID-19), Hong Kong SAR, Research Grants Council of the Hong Kong Special Administrative Region, China.