Understanding the RSV Threat

Respiratory Syncytial Virus (RSV) is a common, highly contagious virus that primarily affects the respiratory system. While frequently enough presenting as a mild cold, RSV can lead to severe complications, particularly in vulnerable populations. Infants and older adults face the greatest risk of developing bronchiolitis and pneumonia, requiring hospitalization.

Each year, RSV infections result in a ample number of hospitalizations. Data indicates that in the EU, approximately 160,000 adults are hospitalized annually due to RSV, with a staggering 92% of these cases occurring in individuals aged 65 and over.Switzerland sees between 3,000 and 6,000 RSV-related hospital admissions each year.

Even older people and patients with immune deficiency can develop a serious course of illness and pneumonia, which leads to hospitalization more frequently enough.

Stefan Kuster, chief physician infectiology at the St.Gallen cantonal hospital

Mresvia: A novel mRNA Vaccine

The recent approval of Moderna’s Mresvia vaccine (mRNA-1345) by Swissmedic represents a pivotal moment in the fight against RSV. This is the first mRNA vaccine approved in Switzerland and the EU for a disease other than COVID-19, showcasing the versatility of mRNA technology.

Mresvia works by delivering an mRNA sequence that codes for a protein found on the surface of the RSV virus. This prompts the body to produce neutralizing antibodies, which then block the virus from penetrating host cells, preventing infection.

Distinguishing Mresvia from Infant Vaccine Trials

It’s crucial to differentiate mresvia from previous attempts to develop an mRNA RSV vaccine for infants. While Moderna explored a similar vaccine (also mRNA-1345) for infants at lower dosages,clinical trials were halted due to observed side effects. Mresvia, though, has demonstrated positive results in Phase 3 trials involving approximately 37,000 adults aged 60 and over across 22 countries, with no serious side effects reported.

Existing RSV Prevention strategies

Mresvia joins other approved RSV vaccines targeting older adults, including protein-based options from Pfizer (Abrysvo) and GSK (Arexvy), both approved as summer 2024. Abrysvo is also approved for use in pregnant women to protect their newborns.

Currently, the Federal Office of Health and the Ekif Vaccination Commission recommend Abrysvo and Arexvy for adults aged 75 and over, as well as individuals aged 60 and over who are at increased risk of complications. Abrysvo is recommended for pregnant women aged 18 and over during the last trimester (October to February) if their due date falls before the end of March.

Considerations and future Implications

While these vaccines offer promising protection, cost coverage remains a key consideration. Currently, RSV vaccinations are not covered by mandatory nursing insurance, and the assumption of costs is under review.

For infants, a monoclonal antibody product called Beyfortus (nirsevimab) is available, administered shortly after birth. This provides immediate protection against RSV, bypassing the need for the infant to develop their own antibodies. Side effects are minimal, typically limited to redness at the injection site.