Against all flu strains
The new vaccine, which induces an immune response to a wide range of strains and subtypes of the influenza virus, has shown high effectiveness, forming a stable immune response, in clinical studies conducted by Mount Sinai Medical Center. A universal vaccine based on chimeric hemagglutinin produces antibodies targeting a fragment of the surface protein of the influenza virus that neutralize various strains. This vaccine has the potential to provide long-term protection after two to three immunizations, eliminating the need for annual revaccination.
According to the World Health Organization, seasonal influenza is a serious public health problem, leading to 650,000 deaths worldwide each year. The most striking example is the 1918 H1N1 pandemic, which killed about 40 million people. Vaccination is the best preventive weapon in the arsenal of public health against seasonal flu. Vaccines usually contain three or four strains of the influenza virus that are circulating in the human population. The disadvantage of the method is that the strains in the vaccines are selected according to forecasts, which often do not coincide with the strains that actually circulate in the population. The situation is aggravated if new pandemic viruses appear, since these outbreaks cannot be predicted and they occur suddenly, and the process of creating new vaccines takes at least six months, as a result of which a large part of the population remains vulnerable.
The chimeric vaccine solves this problem by affecting another part of the hemagglutinin protein, the main surface glycoprotein of the influenza virus, which binds to the receptors of the host cell. Conventional vaccines induce neutralizing antibodies that target the distal part of hemagglutinin – the globular head domain. The virus can avoid neutralization by changing this part of hemagglutinin through the process of antigenic drift. This genetic change leads to the appearance of immunity only to certain strains of the influenza virus, requires frequent changes in the composition and the reintroduction of seasonal vaccines. The new chimeric vaccine, on the contrary, is aimed at the proximal part of the hemagglutinin protein – the stem domain – and neutralizes various strains of the influenza virus both in animal models and in humans.
During phase 1 of the clinical trial, the safety and immunogenicity of the vaccine were evaluated. It was attended by 65 participants in the USA. It was found that the vaccine caused a strong immune response that persisted for at least 18 months after vaccination.
The vaccine design based on the stem domain of hemagglutinin has become the object of close attention of the research community. The elegance of this vaccine lies in the fact that it has not only a wide spectrum of action, but also versatility due to antibodies that can neutralize many types of influenza viruses. This universal vaccine can be especially useful for low- and middle-income countries that do not have the resources or logistics to vaccinate the population against influenza annually.
Article R.Nachbagauer et al. A chimeric hemagglutinin-based universal influenza virus vaccine approach induces broad and long-lasting immunity in a randomized, placebo-controlled phase I trial published in the journal Nature Medicine.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on Mount Sinai: Mount Sinai Researchers Advance a Universal Influenza Virus Vaccine.