Comparative effectiveness of the sars-CoV-2 vaccines during delta dominance

Several vaccines with demonstrated efficacy for coronavirus disease 2019 (Covid-19) are available. The purpose of this study was to evaluate the COVID mRNA based and adenovector based vaccines' differential effectiveness during the time of circulation of the Delta variant and determine what impact this would have on population health and cost effectiveness.

We used de-identified claims in a research database that included vaccination status and Covid-positivity status. Individuals ≥18 years, fully vaccinated with Ad26.COV2·S/J&J/Janssen, mRNA-1273/Moderna, or BNT162b2/Pfizer-BioNTech by September 30, 2021, were included. Outcomes were SARS-CoV-2-infection, emergency department visits, outpatient visits, inpatient hospitalizations, intensive care unit (ICU) transfers, death, and hospice transfers through September 30, 2021.

Among ∼6.5 million fully vaccinated individuals in the UHC Medicare Advantage and our commercially insured research database, mRNA-1273 performed better than BNT162b2 for infection, composite-hospitalization (hospitalization/ICU transfer/hospice transfer/death), and composite-ICU transfer (ICU transfer/hospice transfer/death) caused by B.1.612.7 (delta) variant infection. 26 CE.COV2.S performed worse than BNT162b2 for infection, composite-hospitalization, and composite-ICU transfers. The number needed to vaccinate (NNV) with mRNA1273 to prevent one hospitalization at 90 days was 3130 compared to 26 CE.COV2·S and 15,472 compared to BNT162b2. The NNV with mRNA1273 to prevent one ICU transfer at 90 days was 6358 compared to 26 CE.COV2·S and 34,279 compared to BNT162b2. For every one million individuals vaccinated with BNT162b compared to mRNA-1273, the approximate incremental inpatient cost would be $405,000 and the approximate incremental ICU cost would be $662,000.

The two-dose mRNA vaccines' effectiveness significantly exceeded the single-dose Ad26.COV2·S vaccine's effectiveness from population health and cost-effectiveness perspectives. The mRNA1273 vaccine showed slightly more effectiveness than the BNT162b vaccine.