Moderna Says Vaccine 90% Effective After 6 Months

Ralph Ellis

April 14, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Moderna says its coronavirus vaccine provides strong protection up to 6 months after a second dose.

"Updated cases show continued strong efficacy, including greater than 90% against cases of COVID-19 and greater than 95% against severe cases of COVID-19, with approximately 6 months median follow-up post dose 2," the company said in a statement.

When the FDA granted Moderna emergency use authorization in December, data showed the vaccine was 94% effective.

The pharmaceutical company cited phase III clinical studies conducted through April 9 involving more than 900 cases, including more than 100 severe cases.

Moderna said the results are preliminary and it will share further results throughout the year. The results, though not published in a scientific journal, are consistent with a report in the New England Journal of Medicine which found 33 people who got the Moderna vaccine had a strong antibody response after 6 months, the Moderna statement said.

Earlier this month, Pfizer said its vaccine produced with European partner BioNTech provided strong protection after 6 months.

Pfizer said its vaccine was 91.3% effective against COVID-19 in an analysis of 927 symptomatic people through March 13, as shown by real-world data compiled since the vaccine was given emergency use authorization. The vaccine provided 100% protection against severe disease after 6 months.

This compares to 95% efficacy reported in the interim results announced Nov. 18, 2020.

In its statement, Moderna said the company is running clinical trials on around adolescents 12-17 years old and is enrolling participants 11 years and younger for clinical trials. Dosage will be increased for the younger children if lower doses prove safe, Moderna said.

It's not clear how the Moderna vaccine's effectiveness will hold up against coronavirus variants, but Stéphane Bancel, the Moderna CEO, said the company will address that problem.

"We are looking forward to having the clinical data from our variant-specific booster candidates, as well as clinical data from the phase II-III study of our COVID-19 vaccine in adolescents," Bancel said. "The new preclinical data on our variant-specific vaccine candidates give us confidence that we can proactively address emerging variants. Moderna will make as many updates to our COVID-19 vaccine as necessary until the pandemic is under control."


Moderna. "Moderna Provides Clinical and Supply Updates on COVID-19 Vaccine Program Ahead of 2nd Annual Vaccines Day"