In a recent study posted to the medRxiv* preprint server, the researchers assessed the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger ribonucleic acid (mRNA) booster vaccine on the SARS-CoV-2 Omicron variant.
The waning efficacy of the coronavirus disease 2019 (COVID-19) vaccines has led to the administration of booster vaccines to protect against infection and disease severity. However, there is insufficient knowledge regarding the effectiveness of the booster vaccine against SARS-CoV-2 Omicron BA.2 lineage.
The study and results
The researchers estimated the booster vaccine effectiveness and neutralizing activity induced against the SARS-CoV-2 Omicron BA.2 lineage in the present study.
The team obtained blood samples from a total of 84 physicians practicing at the Kobe University Hospital, Japan. The eligible participants had received their second BNT162b2 dose seven months prior and their booster vaccine dose almost two weeks after the beginning of the study. None of the participants reported a history of COVID-19 infection. A serum neutralizing assay was performed against BA.2 using an authentic virus.
The study results showed that the median age of the participating physicians was 44 years. Most of the participants had very low to no titer of neutralizing antibodies against the SARS-CoV-2 Omicron BA.2 lineage seven months after the primary vaccination with two BNR162b2 doses. However, the titer was observed to increase remarkably two weeks after receiving the booster vaccination.
The study findings showed that the COVID-19 booster vaccine sufficiently induced neutralizing antibodies against the SARS-CoV-2 BA.2 lineage. Furthermore, a booster dose of the BNT162b2 mRNA vaccine effectively elicited a significant cross-neutralizing response against other SARS-CoV-2 variants.
Overall, this indicated that the booster vaccine could successfully curb the rampant transmission of BA.2 and activate memory B cells to stimulate further epitopes that identify neutralizing antibodies that are conserved in all SARS-CoV-2 variants.
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.