Local Researchers Conclude Moderna Remains Effective Up to 5 Months After Second Dose

Researchers at Kaiser Permanente in Pasadena said they have confirmed that Moderna’s COVID-19 vaccine is highly effective for up to five months after the second dose.

The vaccine is 87-percent effective against COVID-19 infection, 96-percent effective against hospitalization, and 98-percent effective against COVID-19 death, results of the research showed.

The study was funded by Moderna, Inc., which produces the vaccine called mRNA-1273 against COVID-19.

The results were published late last month in The Lancet Regional Health – Americas, a suite of open-access general medical journals publishing high-quality, evidence-based research focused on six regions of the world.

“This research provides reassuring evidence of the high effectiveness of the Moderna COVID-19 vaccine in preventing infection, hospitalization, and death from COVID-19,” Dr. Katia Bruxvoort, an adjunct investigator with the Kaiser Permanente Southern California Department of Research and Evaluation, said in a statement.

Bruxvoort said the study included more than 700,000 adults who were racially and ethnically diverse and had a broad range of underlying conditions, including chronic diseases, immuno-compromising conditions, and auto-immune conditions.

The research evaluated the five-month effectiveness of the Moderna COVID-19 mRNA vaccine as part of a five-year observational study within Kaiser Permanente.

Kaiser Permanente said the study included 352,878 recipients of two doses of Moderna COVID-19 vaccine matched to 352,878 unvaccinated individuals by age, sex, race, and ethnicity.

Vaccinated individuals received two doses of Moderna COVID-19 vaccine from December 18, 2020, to March 31 this year. Individuals in both groups were followed until June 30, 2021, the statement added.

“This study adds evidence of real-world Moderna COVID-19 vaccine effectiveness, particularly among the general population,” Dr. Hung Fu Tseng, senior author of the Kaiser Permanente study. “Additionally, our follow-up on these fully vaccinated patients occurred through June 2021, a period that overlapped with the emergence of the delta variant in the United States. Long-term follow-up is ongoing to further evaluate the durability of protection.”

A full report on the Kaiser Permanente study is available at www.sciencedirect.com.