Closing in on a vaccine for RSV
UI researchers continue the progress by developing nextgen, nanoparticle nasal vaccines for RSV
Steve Varga, UI expert on RSV, breaks down what you need to know about the virus and recent progress in vaccine development.
Respiratory syncytial virus, or RSV, is already the leading cause of hospitalization for infants in the U.S., but this year is shaping up to be particularly bad, with pediatric hospitalizations rising rapidly across the country. Unlike flu and COVID-19, which both have safe and effective vaccines that can prevent serious illness, there is currently no vaccine for RSV. However, that may soon change with several promising vaccine candidates and other antiviral therapies at or near the end of phase 3 clinical trials.
Steve Varga, PhD, UI professor of microbiology and immunology, and pathology, who has been studying RSV infection and immunology for almost two decades, breaks down what you need to know about the virus and the recent progress in vaccine development.
What is RSV?
Respiratory syncytial virus (RSV) causes infections of the respiratory tract and lungs. RSV is so common that most children have been infected by 2 years of age, with every child being exposed to the virus by early childhood.
Why is it such a dangerous virus for very young babies?
RSV causes severe infections in young children, particularly those less than 12 months of age. Most severe infections occur in otherwise healthy children. However, children born premature, with a low birth weight, or who have underlying health issues, such as congenital heart defects, run an increased risk of developing severe disease after an RSV infection. Children are especially vulnerable to severe infection because of the smaller size of the airways in their lungs, which can become blocked by mucus that is produced by the body in response to the infection.
In addition to the very young, adults over the age of 65, especially those with one or more health issues, are also at increased risk for RSV.
Why has it been so hard to develop a vaccine for RSV?
Scientists have been trying to develop a vaccine for RSV since the 1960’s, when a formalin-inactivated, killed virus vaccine was developed and tested. Unfortunately, that vaccine caused children to experience worse disease when they were naturally infected by RSV. The terrible failure of that vaccine trial was such a shock to the scientific community that it effectively halted RSV vaccine development for decades. It also led to many of the new safeguards for conducting and monitoring clinical trials that are used today to ensure the safe development of vaccines and therapies. Since then, immunology has also advanced significantly, and scientists now know why the original vaccine failed.
What is the current state of vaccine development?
A major scientific breakthrough occurred a few years ago when scientists determined how to effectively target a key protein on the surface of the virus called the fusion (F) protein. This finding paved the way for the development of several new vaccines against RSV that have recently completed or will soon complete phase 3 clinical trial testing in humans. These initial vaccines will likely be for use either in older adults or in pregnant mothers to protect the child and may make it to market within the next 1-2 years.
Antibodies that can be given to infants to prevent severe RSV infection are also being developed and may also complete testing and make it to market in the next 1-2 years.
What does the future hold?
Although we are likely to have our first RSV vaccine in the next 1-2 years, vaccine development will continue in order to develop vaccines that have the potential to last longer, can be used in young children, or may be more effective than the initial vaccines. My laboratory is working on what could be a second-generation, nanoparticle-based vaccine for RSV that would be administered in the nasal passages to induce better protection in the lung.
Is there anything else you want to highlight?
Although we do not yet have a vaccine for RSV, we do have good, effective vaccines against other respiratory viruses such as influenza and SARS-CoV-2 (that causes COVID-19). I would encourage everyone to get vaccinated against these viruses, which can cause severe disease in both children and older adults.