A vaccine that protects against one of the most widespread of the numerous viruses responsible for the “common cold” is showing promise in a new clinical trial.
Common colds are caused by hundreds of different viruses, including an array of rhinoviruses, coronaviruses, influenza viruses, adenoviruses, and the human respiratory syncytial virus (RSV). The vaccine in development is specifically geared towards this last virus, RSV, a pathogen so infectious it infects practically everyone by the time they're 3 years old.
While most people experience a mild cold-like illness for a week or so and then recover, RSV kills tens of thousands of infants and older adults globally each year. In infants, it’s also the main cause of bronchiolitis, a condition responsible for around 1 in 6 UK hospital admissions for kids, and the main cause of pneumonia in children under 1 in the US. So, for many people, an RSV infection is much more than a mildly annoying case of the sniffles; a vaccine for the disease could prevent thousands of deaths and unnecessary hospitalizations.
Reporting in the Journal of Infectious Diseases, researchers from Danish pharmaceutical company Bavarian Nordic showed their vaccine is safe and effective at protecting against RSV.
It works by introducing a small amount of RSV's surface proteins and internal antigens into the body, allowing the immune system to learn to recognize and respond to the virus. In a randomized and placebo-controlled phase 2 clinical trial involving 420 adults over the age of 55, the researchers showed the vaccine was able to produce a broad and durable antibody and T cell responses against both RSV subtypes. It also appears to keep up this immune response for at least 6 months and can be boosted at 12 months.
In other words: so far, so good. To follow up on these findings, the same researchers will be carrying out a phase 3 trial in elderly people over 60 in 2021. All being well, Bavarian Nordic says it hopes to get the vaccine approved and available by 2024.
Scientists have been working towards an RSV vaccine for over 50 years, although the field has experienced somewhat of a chequered past. Back in the 1960s, an experimental RSV vaccine was given to babies that actually increased the chances of developing a severe infection and hospitalizations. It later became clear that the vaccine was triggering the creation of poorly designed antibodies, which ended up causing an overzealous immune response when the body was infected with RSV. While many lessons were learned from this, the failed study has continued to be a blot on the story of the RSV vaccine.
“A big concern for the scientists involved in RSV vaccine development is to make sure we do not repeat the same situation again,” Dr Fernando P Polack, a scientist from the INFANT Foundation in Buenos Aires who closely studied the 1960s RSV vaccine failure, told Reuters in 2008.
[H/T New Scientist]