New Research Finds Moderna COVID-19 Vaccine “Highly Effective” Against All SARS-CoV-2 Virus Variants

Research by Kaiser Permanente shows that a 2-dose Moderna vaccine is highly effective against hospitalization with COVID-19, but protection against delta infection diminishes over time.

Kaiser Permanente research published today (Dec. 15, 2021) in The British Medical Journal showed that 2 doses of Moderna COVID-19 vaccine were highly effective against all SARS-CoV-2 variants; however, vaccine efficacy against the delta variant declined moderately with increasing time after vaccination.

“We conducted a previous study demonstrating the high effectiveness of the 2 dose Moderna COVID-19 vaccine, but when the delta variant became predominant in early summer 2021, questions arose about its effectiveness against variants,” he said. the lead author of the study. , Katia Bruxvoort, PhD, adjunct researcher at the Kaiser Permanente Southern California Department of Research & Evaluation.

“This study confirmed efficacy against all variants during the study period, although we found a decrease in efficacy against delta infection over time, from 94% efficacy in the first 2 months after vaccination to 80% efficacy at 6 months . The protection against hospitalization by the delta variant remained high with an effectiveness of 98%.”

At Kaiser Permanente in Southern California, molecular diagnostic tests for SARS-CoV-2 are free to members who request them, regardless of whether they have COVID-19 symptoms. Testing is also done prior to hospitalization and many medical procedures. Beginning in March 2021, Kaiser Permanente in Southern California began sending positive SARS-CoV-2 samples from both symptomatic and asymptomatic people to a contracted lab for whole genome sequencing.

This study, funded by Moderna, included 8,153 people who tested positive for SARS-CoV-2, with samples collected from March 1 to July 27, 2021. Among them, 91.3% were unvaccinated, 1.4% had 1 dose of Moderna COVID-19 vaccine, and 7.3% had received 2 doses of Moderna COVID-19 vaccine.

Variants were identified for 5,186 of those samples; 39.4% were delta, 27.7% alpha, 11.4% epsilon, 6.9% gamma, 2.2% iota, 1.4% mu and 11.1% other variants. At the time of this study, the omicron variant had not yet been detected in the Southern California region.

The researchers compared people who tested positive with those who tested negative. Researchers found:

Effectiveness of the 2-dose Moderna COVID-19 vaccine against infection by variant: Delta: 86.7% Mu: 90.4% Alpha: 98.4% Other identified variants: 96 to 98% People taking the 2-dose Moderna COVID-19 vaccine were highly protected against COVID-19 hospitalization associated with the delta variant: Vaccine efficacy against delta hospitalization was high at 97.5% Vaccine effectiveness against hospitalization for non-delta variants was not estimated because hospitalizations with non-delta variants were not found among vaccinated people Among people who had received the 2 doses of Moderna COVID-19 vaccine, there were no hospital deaths Vaccine efficacy of 2 doses of Moderna COVID-19 vaccine against delta infection was 87.9 % in people aged 18 to 64 and 75.2% in people aged 65 and over

“While this study provides reassuring evidence of the effectiveness of 2 doses of Moderna COVID-19 vaccine in preventing COVID-19 infection and hospitalization due to variants, including delta, it also has implications for booster shots,” said lead author of the study, Hung Fu Tseng, PhD, a researcher with the Kaiser Permanente Southern California Department of Research & Evaluation. “The findings of moderately reduced vaccine effectiveness of the Moderna COVID-19 vaccine over time against delta infection support current booster dose recommendations.”

Reference: “Effectiveness of mRNA-1273 against Delta, Mu and other emerging variants: a test-negative study” December 15, 2021, The British Medical Journal.