Positive Topline Results Announced from Pivotal Efficacy Trial of mRNA Vaccine for RSV


Moderna’s mRNA-1345 vaccine targets RSV in older adults.

Moderna has announced positive topline results from a phase 3 pivotal efficacy study of mRNA-1345, the company’s investigational mRNA vaccine targeting respiratory syncytial virus (RSV) in older adults.1

Data from the ConquerRSV clinical trial (NCT05127434) showed that the primary efficacy endpoints of the study, including vaccine efficacy, had been met. Data were reviewed by an independent data and safety monitoring board, and showed a vaccine efficacy of 83.7% (95.88% CI, 66.1% to 92.2%; P <.0001). Based on these results, Moderna “intends to submit for regulatory approval in the first half of 2023,” according to a press release.1

ConquerRSV is a randomized, double-blind, placebo-controlled study including approximately 37,000 adults aged 60 and older across 22 countries. The interim data analysis was based on 64 cases of RSV-associated lower respiratory tract disease with 2 or more symptoms; 55 cases occurred in the placebo group, compared with 9 in the mRNA-1345 group. Among cases with 3 or more symptoms, 17 and 3 cases were noted in the placebo and vaccine groups, respectively.

The ConquerRSV trial is currently ongoing, with additional efficacy analyses planned.

“Today’s results represent an important step forward in preventing lower respiratory disease due to RSV in adults 60 eyars of age and older,” said Moderna CEO Stéphane Bancel. “These data are encouraging, and represent the second demonstration of positive phase 3 trial results from our mRNA infectious disease platform.”

Respiratory diseases, Bancel added, are “a major public health priority given they have a significant health impact and are a leading cause of hospitalization.”

“RSV significantly affects the health of older high-risk adults, particularly those with comorbidities,” added Abdullah Baqui, principal investigator at the Bangladesh study sites and a professor in the department of international health and director of the International Center for Maternal and Newborn Health at the Johns Hopkins Bloomberg School of Public Health. “This trial will help to understand the role of severe acute respiratory infections in older adult populations and inform the future implementation of vaccines in adults in lower-resource areas.”

Moderna intends to submit these data for peer-reviewed publication and present at upcoming scientific meetings.


  1. Moderna announces mRNA-1345, an investigational respiratory syncytial virus (RSV) vaccine, has met primary efficacy endpoints in phase 3 trial in older adults. News release. Moderna. January 17, 2023. Accessed January 17, 2023. https://investors.modernatx.com/news/news-details/2023/Moderna-Announces-mRNA-1345-an-Investigational-Respiratory-Syncytial-Virus-RSV-Vaccine-Has-Met-Primary-Efficacy-Endpoints-in-Phase-3-Trial-in-Older-Adults/default.aspx
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