The benefit-risk profile of the Omicron-adapted BNT162b2 COVID-19 vaccine is favorable for previously boosted individuals aged 12 years and older, according to results of a study published in Clinical Infectious Diseases.
In an ongoing phase 2/3 randomized trial (ClinicalTrials.gov Identifier: NCT05472038), researchers assessed the immunogenicity and safety of an Omicron-adapted COVID-19 booster (BNT162b2-Omi.BA.4/BA.5). Eligible study patients were aged 12 years and older and had received a third dose of the original BNT162b2 vaccine 5 to 12 months prior to enrollment. The Omicron-adapted vaccine was administered to all patients as a second booster dose. The researchers divided patients into 2 cohorts. In the first cohort, patients aged 12 to 17 years received a 30-ug dose, and those aged 18 to 55 years and those older than 55 were randomly assigned 1:1 to receive either 30- or 60-μg doses. In the second cohort, patients aged 18 years and older received a 30-μg dose.
The final analysis included 939 patients; demographic characteristics were well balanced across age and vaccine cohorts (43% men; 82% White; 12% Hispanic). Overall, 36% of patients had obesity, and 68% had evidence of prior COVID-19 infection.
At 1 month following vaccination, the Omicron-adapted bivalent vaccine was superior to the original BNT162b2 vaccine in terms of neutralizing titers in patients older than 55 years, with a model-adjusted geometric mean ratio (GMR) of 2.91 (95% CI, 2.45-3.44). Further analysis of patients in this age group indicated that the vaccine was noninferior to the original BNT162b2 vaccine with respect to seropositivity rates (adjusted difference, 26.77%; 95% CI, 19.59-33.95).
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[T]he totality of these immunogenicity and safety results suggest an anticipated improved clinical benefit against COVID-19 due to Omicron BA.4/BA.5 with bivalent BNT162b2-Omi.BA.4/BA.5…
Noninferior immune responses to the ancestral SARS-CoV-2 strain were also observed among patients older than 55 years who received the Omicron-adapted booster. In regard to immune responses to Omicron BA.4/B.5, noninferiority was observed between patients older than 55 years and those between 18 and 55 years.
Administration of the Omicron-adapted booster at a 30-μg dose elicited robust immune responses among patients across all age groups, whereas a 60-μg dose elicited robust immune responses in those aged 15 to 55 years and those older than 55 years.
Of note, BA.4/B.5 geometric mean titers at 1 month following vaccination were higher among patients across all age groups who were positive vs negative for COVID-19 infection at baseline.
In the safety analysis, the most common local and systemic reactions were pain at the injection site and fatigue, respectively. Mild to moderate reactogenicity events were more common among younger (age range, 12-55 years) vs older patients (age, >55 years), as well as in those who received the 30-μg dose. Overall, the rate of adverse events ranged between 6.1% and 8.2% across all patient groups.
Limitations of this study include the short follow-up period, the predominance of White patients, and the inability to assess vaccine efficacy due to the lower number of COVID-19 diagnoses.
According to the researchers, “[T]he totality of these immunogenicity and safety results suggest an anticipated improved clinical benefit against COVID-19 due to Omicron BA.4/BA.5 with bivalent BNT162b2-Omi.BA.4/BA.5…”
Disclosure: This research was supported by Pfizer and BioNTech, and multiple study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
This article originally appeared on Infectious Disease Advisor
