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Effectiveness of the monovalent XBB.1.5 COVID-19 vaccines: A systematic review and meta-analysis
Hsin Ma1, Yi-Yu Chen2, Wei-Liang Shih3
1Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan; Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.
Insights
The monovalent XBB.1.5 vaccine offered significant protection against severe COVID-19 outcomes before the JN.1 variant emerged. Updated vaccinations are crucial to maintain defense against new SARS-CoV-2 strains.
Area of Science:
- Immunology
- Virology
- Public Health
Background:
- Coronavirus disease 2019 (COVID-19) remains a concern despite the end of its pandemic status, with XBB as the predominant SARS-CoV-2 variant.
- Population immunity levels raise questions about the effectiveness of current monovalent XBB.1.5 vaccines.
Purpose of the Study:
- To evaluate the effectiveness of the monovalent XBB.1.5 COVID-19 vaccine in adults during the 2023-2024 season.
- To assess vaccine effectiveness (VE) against infection, hospitalization, and death from SARS-CoV-2.
- To analyze VE trends over time and against emerging variants like JN.1.
Main Methods:
- Systematic review of studies published up to November 30, 2024, sourced from PubMed, Embase, Web of Science, and Cochrane Central.
- Inclusion of 21 studies with over 53 million participants.
- Random-effects model meta-analyses were performed.
Main Results:
- Initial VE against infection, hospitalization, and death was 52.9%, 64.4%, and 77.3%, respectively, declining by month five.
- Effectiveness against the JN.1 variant showed a significant drop: 47% for infection, 32% for hospitalization, and 26% for death.
- VE against hospitalization was comparable between individuals over 60 and under 60 years old.
Conclusions:
- XBB.1.5 vaccines provided substantial protection against severe COVID-19 prior to the JN.1 variant's dominance.
- The study highlights the necessity of updated COVID-19 vaccinations to counter evolving SARS-CoV-2 variants and maintain public health protection.
Background:
Coronavirus disease 2019 (COVID-19) remains a public health concern even after its pandemic status officially ended on May 5, 2023, when XBB became the globally predominant SARS-CoV-2 variant. Amid population immunity, the benefit of the monovalent XBB.1.5 vaccines remains uncertain.
Methods:
This systematic review searched PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials through November 30, 2024, for studies evaluating the effectiveness of XBB.1.5 vaccines in adults during the 2023-2024 season. Meta-analyses were conducted using a random-effects model (PROSPERO registration: CRD42024513730).
Results:
Twenty-one eligible studies, with a total of 53,396,781 participants, were included. Vaccine effectiveness (VE) in the first month post-vaccination was 52.9 % (95 % CI: 47.6 %-57.6 %) against SARS-CoV-2 infection, 64.4 % (95 % CI: 59.3 %-68.9 %) against COVID-19-related hospitalization, and 77.3 % (95 % CI: 67.1 %-84.3 %) against COVID-19-related death. However, by the fifth month, VE declined to 26.7 %, 52.3 %, and 69.4 %, respectively. Notably, against the JN.1 variant that replaced XBB in December 2023, VE against infection, hospitalization, and death dropped significantly by 47 % (from 53.7 % to 28.3 %), 32 % (from 67.8 % to 46.2 %), and 26 % (from 77.3 % to 57.1 %), respectively. VE against hospitalization in individuals aged >60 years was not inferior to that in those aged <60 years (57.2 % versus 49.2 %; subgroup difference, p = 0.24).
Conclusion:
XBB.1.5 vaccines provided substantial protection against severe COVID-19 outcomes in the 2023-2024 season prior to the emergence of the JN.1 variant. These findings underscore the need for updated COVID-19 vaccinations to maintain protection against evolving SARS-CoV-2 variants.
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