Durability of mRNA-1273 against COVID-19 in the time of Delta: Interim results from an observational cohort study

Abstract

Background We conducted a prospective cohort study at Kaiser Permanente Southern California to study the vaccine effectiveness (VE) of mRNA-1273 over time and during the emergence of the Delta variant. Methods The cohort for this planned interim analysis consisted of individuals aged ≥18 years receiving 2 doses of mRNA-1273 through June 2021, matched 1:1 to randomly selected unvaccinated individuals by age, sex, and race/ethnicity, with follow-up through September 2021. Outcomes were SARS-CoV-2 infection, and COVID-19 hospitalization and hospital death. Cox proportional hazards models were used to estimate adjusted hazard ratios (aHR) with 95% confidence intervals (CIs) comparing outcomes in the vaccinated and unvaccinated groups. Adjusted VE (%) was calculated as (1-aHR)x100. HRs and VEs were also estimated for SARS-CoV-2 infection by age, sex, race/ethnicity, and during the Delta period (June-September 2021). VE against SARS-CoV-2 infection and COVID-19 hospitalization was estimated at 0-<2, 2-<4, 4-<6, and 6-<8 months post-vaccination. Results 927,004 recipients of 2 doses of mRNA-1273 were matched to 927,004 unvaccinated individuals. VE (95% CI) was 82.8% (82.2–83.3%) against SARS-CoV-2 infection, 96.1% (95.5–96.6%) against COVID-19 hospitalization, and 97.2% (94.8–98.4%) against COVID-19 hospital death. VE against SARS-CoV-2 infection was similar by age, sex, and race/ethnicity, and was 86.5% (84.8–88.0%) during the Delta period. VE against SARS-CoV-2 infection decreased from 88.0% at 0-<2 months to 75.5% at 6-<8 months. Conclusions These interim results provide continued evidence for protection of 2 doses of mRNA-1273 against SARS-CoV-2 infection over 8 months post-vaccination and during the Delta period, and against COVID-19 hospitalization and hospital death.

COVID-19 Severity and Waning Immunity After up to 4 mRNA Vaccine Doses in 73 608 Patients With Cancer and 621 475 Matched Controls in Singapore

“…Vaccination-differentiated management measures directed toward reducing exposure of unvaccinated and partially vaccinated patients may have resulted in lower infection rates, although higher incidence of severe disease was still observed in unvaccinated and partially vaccinated individuals. This persisted into the omicron wave, despite the variant being associated with decreased severity compared with preceding variant strains …”

“…This persisted into the omicron wave, despite the variant being associated with decreased severity compared with preceding variant strains. [37][38][39][40][41][42] The findings of this cohort study provide evidence that patients receiving a third vaccine dose derive additional protection against severe infection from both the delta and omicron variants, consistent with results from previous studies. 16,[43][44][45][46][47][48] Between September 15, 2021, to November 11, 2022, of the total 4 756 102 doses administered to the study population, 4 462 301 (93.8%) were monovalent mRNA vaccines, 76 247 (1.6%) were bivalent mRNA vaccines and the remaining 217 554 (4.6%) were non-mRNA vaccines.…”

Vaccine effectiveness of the mRNA-1273 3-dose primary series against COVID-19 in an immunocompromised population: A prospective observational cohort study

“…The study setting is described in detail in prior publications utilizing similar data [15] , [16] . Briefly, Kaiser Permanente Southern California (KPSC) is an integrated health care system providing care to >4.6 million socio-demographically diverse health plan members in Southern California [17] .…”

“…Severe COVID-19 disease included COVID-19 hospitalization and COVID-19 mortality (death during COVID-19 hospitalization). COVID-19 hospitalization was defined as hospitalization with a SARS-CoV-2 positive test or a COVID-19 diagnosis, or a hospitalization occurring ≤7 days after a SARS-CoV-2 positive test and confirmed by pre-determined criteria or manual chart reviews [15] . We considered a SARS-CoV-2 infection incident if there was no evidence of a COVID-19 diagnosis code or SARS-CoV-2 positive test in the 90 days prior.…”

Clinical impact and cost-effectiveness of the updated COVID-19 mRNA Autumn 2023 vaccines in Germany

“…The safety and efficacy of both mRNA-1273 and BNT162b2 in reducing the risk of SARS-CoV-2 infection in the general population and in adolescents have been demonstrated in numerous phase 3 clinical trials [14][15][16]. Subsequent observational studies have provided evidence of the protection offered by two doses of both mRNA vaccines against SARS-CoV-2 infection and against COVID-19 hospitalisation and hospital death [17][18][19][20][21][22], despite the emergence of variants [23][24][25], although several observational studies have demonstrated that the differences in formulation impact vaccine effectiveness [17][18][19][20][21][22].…”