Moderna COVID-19 Vaccine Remains Very Effective 5 Months After 2nd Dose

Kaiser Permanente research shows that the Moderna COVID-19 vaccine is 87% effective in preventing COVID-19 infection and more than 95% effective in preventing severe COVID-19.

Kaiser Permanente study in Southern California, published Nov. 25, 2021 in The Lancet Regional Health – Americas, confirmed high effectiveness of the Moderna COVID-19 vaccine for up to 5 months after the second dose. Effectiveness was 87% against COVID-19 infection, 96% against COVID-19 hospitalization and 98% against death from COVID-19.

“This study provides reassuring evidence of the high effectiveness of the Moderna COVID-19 vaccine in preventing infection, hospitalization, and death from COVID-19,” said Katia Bruxvoort, PhD, adjunct researcher at the Kaiser Permanente Southern California Department of Research & Evaluation. “One of the important aspects of this study was that it included more than 700,000 adults who were racially and ethnically diverse and had a wide variety of underlying conditions, including chronic diseases, immune-compromising conditions, and autoimmune disorders.”

This study evaluated the 5-month effectiveness of the Moderna COVID-19 mRNA vaccine as part of a 5-year observational study at Kaiser Permanente, an integrated health care organization with 4.7 million members in Southern California.

The study included 352,878 recipients of 2 doses of Moderna COVID-19 vaccine, corresponding to 352,878 unvaccinated individuals based on age, gender, race and ethnicity. Vaccinated individuals received 2 doses of Moderna COVID-19 vaccine from December 18, 2020 to March 31, 2021. Individuals in both groups were followed until June 30, 2021.

During follow-up, COVID-19 infections occurred in 289 vaccinated patients and 1,144 unvaccinated patients. The efficacy of the vaccine against COVID-19 infection was 87%. COVID-19 hospitalization occurred among 13 vaccinated and 182 unvaccinated patients, and in-hospital COVID-19 deaths among 1 vaccinated and 25 unvaccinated patients. Vaccine efficacy against hospitalization from COVID-19 was 96% and vaccine efficacy against in-hospital deaths from COVID-19 was 98%. Vaccine efficacy against COVID-19 infection remained high across age, gender, racial and ethnic subgroups, with results ranging from 83% to 92%. Vaccine efficacy was higher against symptomatic COVID-19 (88%) than against asymptomatic COVID-19 (73%). From March to June 2021, there were 5,619 SARS-CoV-2 positive copies that were successfully sequenced. The most common variants were alpha (42%), epsilon (18%), delta (12%) and gamma (9%), with delta reaching 54% of variants by June 2021.

“This study adds evidence of the true effectiveness of Moderna COVID-19 vaccines, particularly among the general population,” said Hung Fu Tseng, PhD, a researcher with the Kaiser Permanente Southern California Department of Research & Evaluation and the senior author. of the study. “In addition, our follow-up of these fully vaccinated patients was until June 2021, a period that overlapped with the emergence of the delta variant in the United States. A long-term follow-up is underway to further evaluate the durability of the protection.”

Reference: “Real-world effectiveness of the mRNA-1273 vaccine against COVID-19: interim results from a prospective observational cohort study” by Katia J. Bruxvoort, Lina S. Sy, Lei Qian, Bradley K. Ackerson, Yi Luo, Gina S. Lee, Yun Tian, ​​Ana Florea, Harpreet S. Takhar, Julia E. Tubert, Carla A. Talarico, and Hung Fu Tseng, Nov. 25, 2021, The Lancet Regional Health – Americas.
DOI: 10.1016/j.lana.2021.100134

The study was funded by Moderna, Inc.