Fact check: The Covid bivalent vaccine affords protection.
The Cleveland clinic study has some surprising results, particularly if you expect the vaccine to be safe and effective.
The more vaccine doses you have had, the more likely you are to catch Covid.
The Cleveland Clinic gave the new bivalent vaccine to 51,017 of their employees. The really significant part of the results of this study is that the risk of COVID-19 increased with time since most recent prior COVID-19 episode and with the number of vaccine doses previously received.
This is now a peer reviewed study - the preprint was initially released to medrxiv on December 22, 2022.
The vaccine offered modest protection overall against COVID-19 while the BA.4/5 lineages were the dominant circulating strains, afforded less protection when the BQ lineages were dominant, and effectiveness was not demonstrated when the XBB lineage arrived.
Nabin K Shrestha and others, Effectiveness of the Coronavirus Disease 2019 (COVID-19) Bivalent Vaccine, Open Forum Infectious Diseases, 2023;, ofad209, https://doi.org/10.1093/ofid/ofad209 https://academic.oup.com/ofid/advance-article/doi/10.1093/ofid/ofad209/7131292
Abstract
Background
The purpose of this study was to evaluate whether a bivalent COVID-19 vaccine protects against COVID-19.
Methods
Employees of Cleveland Clinic in employment when the bivalent COVID-19 vaccine first became available, were included. Cumulative incidence of COVID-19 over the following 26 weeks was examined. Protection provided by vaccination (analyzed as a time-dependent covariate) was evaluated using Cox proportional hazards regression, with change in dominant circulating lineages over time accounted for by time-dependent coefficients. The analysis was adjusted for the pandemic phase when the last prior COVID-19 episode occurred, and the number of prior vaccine doses.
Results
Among 51017 employees, COVID-19 occurred in 4424 (8.7%) during the study. In multivariable analysis, the bivalent vaccinated state was associated with lower risk of COVID-19 during the BA.4/5 dominant (HR, .71; 95% C.I., .63-.79) and the BQ dominant (HR, .80; 95% C.I., .69-.94) phases, but decreased risk was not found during the XBB dominant phase (HR, .96; 95% C.I., .82-.1.12). Estimated vaccine effectiveness (VE) was 29% (95% C.I., 21%-37%), 20% (95% C.I., 6%-31%), and 4% (95% C.I., -12%-18%), during the BA.4/5, BQ, and XBB dominant phases, respectively. Risk of COVID-19 also increased with time since most recent prior COVID-19 episode and with the number of vaccine doses previously received.
Conclusions
The bivalent COVID-19 vaccine given to working-aged adults afforded modest protection overall against COVID-19 while the BA.4/5 lineages were the dominant circulating strains, afforded less protection when the BQ lineages were dominant, and effectiveness was not demonstrated when the XBB lineages were dominant.