Large Healthcare Workers Study: Pfizer mRNA Booster Vaccine Fails to Protect Against Symptomatic Infection After 30 Days

What happens to COVID-19 booster effectiveness after a period of time after vaccination? A team of public health researchers from the nation of Georgia sought to find out, investigating COVID-19 vaccine effectiveness among a group of healthcare workers during the Omicron Period. A critical effort to better inform and direct vaccination policy, the researchers in this study led by Caleb L. Ward Public Health Institute of Georgia and colleagues measured COVID-19 vaccine effectiveness against laboratory-confirmed symptomatic infection in HCWs in the country of Georgia from January – June 2022, during a period of Omicron circulation. The study results were uploaded to medRxiv so still need to be peer-reviewed. Conducting the cohort study of HCWs in six hospitals in Georgia, they started enrolling the participants by early 2021. Participants completed weekly symptom questionnaires. Symptomatic HCWs were tested by RT-PCR and/or rapid antigen test (RAT). Participants were also routinely tested, at varying frequencies during the study period, for SARS-CoV-2 by RT-PCR or RAT, regardless of symptoms. Serology was collected quarterly throughout the study and tested by electrochemiluminescence immunoassay for SARS-CoV-2 antibodies. Ward and colleagues estimated absolute and relative vaccine effectiveness of a first booster dose compared to a primary vaccine series as (1-hazard ratio)*100 using Cox proportional hazards models. The conclusion was that in the nation of Georgia, a first booster dose vaccine effectiveness against symptomatic SARS-CoV-2 infection among HCWs was moderately effective but waned very quickly during Omicron. Increased efforts to vaccinate priority groups in Georgia, such as healthcare workers, prior to periods of anticipated high COVID-19 incidence are essential for vaccination with this class of vaccine to work at all. The findings don’t bode well for Pfizer, the majority vaccine used for booster. In fact, after 30 days, the mRNA vaccine has a negative impact when measuring absolute vaccine effectiveness. This is frankly, an ominous result. 

What are the findings?