Journal Article

Effectiveness of mRNA-1273 against delta, mu, and other emerging variants of SARS-CoV-2: test negative case-control study

Paila, Yamuna D, Tian, Yun, Tseng, Hung Fu, Aragones, Michael, Bruxvoort, Katia J, Takhar, Harpreet S, Sy, Lina S, Lee, Gina S, Talarico, Carla A, Florea, Ana, Ku, Jennifer H, Ackerson, Bradley K, Qian, Lei, Luo, Yi, Tubert, Julia E

2021

Overview

AbstractObjectivesTo evaluate the effectiveness of the mRNA-1273 vaccine against SARS-CoV-2 variants and assess its effectiveness against the delta variant by time since vaccination.DesignTest negative case-control study.SettingKaiser Permanente Southern California (KPSC), an integrated healthcare system.ParticipantsAdult KPSC members with a SARS-CoV-2 positive test sent for whole genome sequencing or a negative test from 1 March 2021 to 27 July 2021.InterventionsTwo dose or one dose vaccination with mRNA-1273 (Moderna covid-19 vaccine) ≥14 days before specimen collection versus no covid-19 vaccination.Main outcome measuresOutcomes included infection with SARS-CoV-2 and hospital admission with covid-19. In pre-specified analyses for each variant type, test positive cases were matched 1:5 to test negative controls on age, sex, race/ethnicity, and specimen collection date. Conditional logistic regression was used to compare odds of vaccination among cases versus controls, with adjustment for confounders. Vaccine effectiveness was calculated as (1–odds ratio)×100%.ResultsThe study included 8153 cases and their matched controls. Two dose vaccine effectiveness was 86.7% (95% confidence interval 84.3% to 88.7%) against infection with the delta variant, 98.4% (96.9% to 99.1%) against alpha, 90.4% (73.9% to 96.5%) against mu, 96-98% against other identified variants, and 79.9% (76.9% to 82.5%) against unidentified variants (that is, specimens that failed sequencing). Vaccine effectiveness against hospital admission with the delta variant was 97.5% (92.7% to 99.2%). Vaccine effectiveness against infection with the delta variant declined from 94.1% (90.5% to 96.3%) 14-60 days after vaccination to 80.0% (70.2% to 86.6%) 151-180 days after vaccination. Waning was less pronounced for non-delta variants. Vaccine effectiveness against delta infection was lower among people aged ≥65 years (75.2%, 59.6% to 84.8%) than those aged 18-64 years (87.9%, 85.5% to 89.9%). One dose vaccine effectiveness was 77.0% (60.7% to 86.5%) against infection with delta.ConclusionsTwo doses of mRNA-1273 were highly effective against all SARS-CoV-2 variants, especially against hospital admission with covid-19. However, vaccine effectiveness against infection with the delta variant moderately declined with increasing time since vaccination.

• Publisher: British Medical Journal Publishing Group,BMJ Publishing Group LTD
• Subject: 2019-nCoV Vaccine mRNA-1273 - administration & dosage / 2019-nCoV Vaccine mRNA-1273 - immunology / Adolescent / Adult / Aged / California / Case-Control Studies / Coronaviruses / COVID-19 - mortality / COVID-19 - prevention & control / COVID-19 - virology / COVID-19 vaccines / Disease / Drug stores / Effectiveness / Electronic health records / Female / Genomes / Hispanic people / Hospitalization - statistics & numerical data / Hospitals / Humans / Infections / Laboratories / Male / Middle Aged / mRNA / SARS-CoV-2 / Severe acute respiratory syndrome coronavirus 2 / Vaccination / Vaccination - statistics & numerical data / Vaccine Efficacy / Vaccines / Whole genome sequencing / Young Adult