Pfizer Shares Good News About RSV Vaccine for Adults With Weak Immune Systems

Pfizer recently shared exciting results from a phase 3 clinical trial of its vaccine, ABRYSVO, which aims to protect people from RSV (respiratory syncytial virus). The trial showed that the vaccine works well in adults with weakened immune systems. A single dose of the vaccine helped protect against both RSV-A and RSV-B, which are common types of the virus.

The trial, called the MONeT study, looked at 203 adults with serious health conditions, such as lung cancer, kidney failure requiring dialysis, and those who have received organ transplants. The study tested both one and two doses of the vaccine, but the single dose had the best results. The safety of the vaccine matched what was seen in earlier trials.

Pfizer has also received approval from the FDA for a new way to package ABRYSVO, making it easier to store and prepare the vaccine. This adds to Pfizer’s growing list of approvals for ABRYSVO, including in Europe, the UK, Canada, and other countries.

How Did We Get Here?

In August 2023, Pfizer’s RSV vaccine was approved in the U.S. for use in pregnant women to protect their babies from RSV. The vaccine is given to mothers during their pregnancy, between 32 and 36 weeks, to help protect newborns from severe RSV infections in the first six months of life.

This approval was based on results from a trial called MATISSE. In this study, the vaccine was 81.8% effective in preventing serious RSV-related illness in babies. The study involved over 7,000 participants in 18 countries and showed a big drop in severe RSV cases among babies born to vaccinated mothers.

More recently, in April 2024, Pfizer shared more good news from the MONeT trial. This study looked at adults aged 18 to 59 who are at high risk for severe RSV-related lung infections. The trial showed that the vaccine boosted the body’s defenses against both RSV-A and RSV-B and was safe, matching results seen in an earlier study involving older adults.

About ABRYSVO

ABRYSVO is designed to protect people aged 60 and older from serious RSV infections. It’s also used in pregnant women to help protect their newborns from RSV. RSV is a virus that can cause serious lung problems, especially in older adults and people with certain health issues.

Looking ahead, Pfizer plans to present its latest findings from the MONeT trial to regulators, hoping to expand the vaccine’s use for people with weakened immune systems. Pfizer is also working on trials to use ABRYSVO in children aged 2 to 18 years. With these efforts, Pfizer aims to protect more people at high risk from RSV-related illnesses.

An original version of this article was published on sister site Contagion.

References

1. ^{Pfizer Announces Top-Line Results of ABRYSVO® for RSV in Immunocompromised Adults. Published August 12, 2024. Accessed August 12, 2024.https://www.pfizer.com/news/press-release/press-release-detail/pfizer-announces-top-line-results-abrysvor-rsv}
2. ^{Pfizer Announces Positive Top-Line Results from Phase 3 Study of ABRYSVO® in Adults Aged 18 to 59 at Increased Risk for RSV Disease. Pfizer Press release. April 9, 2024. Accessed August 12, 2024. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-announces-positive-top-line-results-phase-3-study-1}
3. ^{Bigica A. FDA Approves Pfizer's Maternal RSV Vaccine Abrysvo to Protect Infants. August 21, 2023. Accessed August 12, 2024. https://www.contagionlive.com/view/fda-approves-pfizer-maternal-rsv-vaccine-rsvpref-abrysvo-to-protect-infants}