Booster dose of BNT162b2 mRNA vaccine induces a high cross-neutralizing response against SARS-CoV-2 variants

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.

Conclusion

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.

*Important notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Written by

Bhavana Kunkalikar

Bhavana Kunkalikar is a medical writer based in Goa, India. Her academic background is in Pharmaceutical sciences and she holds a Bachelor's degree in Pharmacy. Her educational background allowed her to foster an interest in anatomical and physiological sciences. Her college project work based on ‘The manifestations and causes of sickle cell anemia’ formed the stepping stone to a life-long fascination with human pathophysiology.