Moderna announced on Friday that the Food and Drug Administration (FDA) has postponed the approval of its vaccine for respiratory syncytial virus (RSV) to the end of May due to "administrative constraints" at the agency.

The FDA was initially expected to make a decision on the RSV shot on Sunday. However, Moderna clarified that the delay is not related to any safety, efficacy, or quality issues concerning the vaccine.

Investors are closely monitoring the upcoming approval as Moderna seeks to recover from the decline in its COVID-related business last year. If approved, the RSV shot would mark the company's second product launch in the U.S., following its COVID vaccine. Additionally, it would be the third RSV vaccine in the market after Pfizer and GSK introduced their shots last year.

Moderna's RSV vaccine remains on track for review by an advisory panel to the Centers for Disease Control and Prevention (CDC) during a meeting scheduled for June 26 and 27. This panel will vote on recommendations for the vaccine's use and target population before it can be launched in the market.

The RSV vaccine has been undergoing testing in older adults, who are more susceptible to severe RSV cases. RSV is responsible for thousands of deaths and hospitalizations among seniors annually, according to CDC data.

Dr. Stephen Hoge, president of Moderna, expressed gratitude to the FDA for their continued efforts and diligence. He stated that Moderna looks forward to assisting the agency in completing the review process and participating in the advisory meeting in June.

The approval of the RSV vaccine would showcase the versatility of Moderna's messenger RNA (mRNA) platform beyond COVID treatment. The company is leveraging this technology to address various diseases, including cancer and norovirus, a highly contagious stomach bug.

Investors have high expectations for Moderna's mRNA product pipeline, with shares of the company rising more than 20% this year after experiencing a significant decline in 2023.