Universal flu vaccine trialled by NHS
A large trial of NHS patients is now underway to investigate the efficacy of a new universal flu vaccine, which researchers hope will protect more people against influenza, particularly older people. Last season’s (2016–17) influenza vaccine was effective in only 40% of people overall, and was found to have no significant effectiveness in ≥65-year-olds. This is believed to be because the immune system weakens with age, in addition to the vaccine being ineffective against certain strains of the virus.
The trial is being conducted by the University of Oxford, supported by the National Institute for Health Research (NIHR). About 10,000 NHS patients aged over 65 years registered at six GP practices in Berkshire and Oxfordshire will be invited to take part and the recruitment target is 500. The patients will receive their regular annual flu vaccination in combination with either the new universal vaccine or a placebo injection. As well as examining the efficacy of the new vaccine in flu prevention, the study will also look at the severity and duration of illness in those who still get the flu.
The new vaccine, called MVA-NP+M1, uses a different mechanism of action to currently used flu vaccines. Existing vaccines use the proteins haemagglutinin and neuraminidase, which lie on the surface of flu cells to stimulate the body’s immune system to produce antibodies. However, these surface proteins change with new strains of the virus, and so the flu vaccine needs to be changed annually. Sometimes, even by the time the vaccine has been produced, the strain of the virus that is causing the most illness has also changed.
In contrast, the new vaccine uses the core proteins of the virus, which remain virtually unchanged in all influenza A viruses (the type that are responsible for the most morbidity and mortality). Moreover, the new vaccine stimulates the immune system to boost influenza-specific T cells rather than antibodies, which can help fight more than one type of flu virus. The researchers also hope that protection from the new vaccine will last longer than a year, meaning that in the future, flu vaccinations may only need to be given once every five years, for example. The current trial is expected to take two years to complete, and if the vaccine is found to be safe and effective, it could be licensed for wider use.