Chilean RSV Vaccine to Begin Clinical Trials in Europe: Who Will Benefit?

One of Europe's health regulatory agencies has given the green light for a phase 2 clinical trial of the human Respiratory Syncytial Virus (RSV) vaccine. This vaccine is being developed by a team of Chilean researchers led by Dr. Alexis Kalergis, a professor at the Faculty of Biological Sciences at Pontificia Universidad Católica de Chile (UC Chile) and Director of the Millennium Institute of Immunology and Immunotherapy (IMII). 

But what does phase 2 entail?

Phase 2 of this clinical trial seeks to confirm the vaccine's safety and its ability to generate an immune response in a broader population, marking an essential step toward its final approval and widespread application. Adults over age 60, a group especially susceptible to developing severe RSV-related complications, will be included in this phase.

“This approach will not only deepen the evaluation of the formula but also gather relevant information that supports its potential implementation as an effective tool to protect the most vulnerable populations,” says Dr. Kalergis. 

Studies have shown that the respiratory syncytial virus (RSV) represents a significant health burden, causing around 3.4 million hospitalizations annually worldwide and nearly 5% of global acute lower respiratory infection episodes in infants and children under age 5. In a non-COVID year, RSV is the most prevalent respiratory disease nationwide, resulting in nearly 5,000 hospitalizations annually. 

According to Dr. Kalergis, “the approval of a phase 2 clinical study by one of Europe's health regulatory agencies is a historic moment for national science. This crucial step confirms Chile's position as an international leader in the fight against one of the main causes of serious respiratory diseases in infants, young children, and the elderly worldwide.” 

Preclinical Results and Initial Trials

Before this phase, the vaccine underwent rigorous preclinical studies in Chile and abroad, as well as a phase 1 trial in healthy young adults conducted in Chile. Dr. Kalergis went on to explain that “these results, which demonstrated the safety and efficacy of the vaccine, were crucial for obtaining EMA (European Medicines Agency) authorization to continue the trials in Europe.” If positive results are obtained in a phase 3 trial, the vaccine could be approved for widespread distribution.

The first Chilean vaccine against RSV is now closer to becoming a reality, thanks to support from both public and private funding, along with collaboration between UC Chile and the Angelini Group. 

“We hope that the results from this phase 2 trial will be favorable and allow us to move forward to a phase 3 clinical trial, in which a larger number of participants will be recruited to assess its efficacy against natural exposure to the virus,” adds Dr. Pablo González, professor at the Faculty of Biological Sciences, IMII researcher, and fellow leader of the study.  

For UC Chile researchers, this progress reflects Chilean science's commitment to global health. Dr. Susan Bueno, UC Chile academic and scientific director of the study, stated, “This advancement represents not only a milestone for Chilean science but also highlights the impact of international collaboration in medical research.”

Dr. Hernán Peñaloza, UC Chile academic, commented that: “European countries with advanced infrastructure and experience in clinical trials are strategic allies in validating this vaccine, which aims to protect the most vulnerable populations against RSV.”  

It is worth noting that the European Medicines Agency (EMA) is the authority responsible for evaluating medicines in the European Union. The EMA follows a review process for approving clinical trials, including vaccine development phases.