Universal Flu vaccine
Influenza virus epidemics harm the health and take the lives of many people around the world every year. The main problem is that vaccines protect against the disease only when they exactly match the strains circulating in the population. However, antigenic drift can cause significant discrepancies between the vaccine and circulating strains, this significantly reduces the effectiveness of the vaccine, and it takes months to create an up-to-date vaccine.
A team led by researchers from the Icahn School of Medicine at Mount Sinai has released interim results of a randomized, blind, placebo-controlled phase 1 trial of a universal influenza vaccine based on the so-called chimeric hemagglutinin (cHA) in healthy adult volunteers at two centers in the United States.
The hemagglutinin protein is located on the capsid (outer shell) of the influenza virus and carries the virus inside the host cell. It consists of two parts: a rapidly changing "head" and a single "stem" for different strains. The researchers focused their efforts on developing a vaccine against hemagglutinin stem. The study, conducted in collaboration with the international non-profit organization PATH, the Cincinnati Children's Hospital Medical Center, the Duke Early Phase Clinical Research Department and the University of Chicago, was supposed to test the ability of chimeric candidates of a universal influenza vaccine based on type I hemagglutinin (H1) to induce broadly cross-reactive antibodies targeting the stem part of hemagglutinin-expressing viruses flu.
The study participants were randomized to one of three hemagglutinin-based chimeric vaccine regimens or to one of two placebo groups. The vaccine regimens included: 1) chimeric intranasal live attenuated vaccine based on hemagglutinin H8/1 on day 1, followed by non-adjuvant chimeric H5/1 intramuscular inactivated vaccine on day 85;
2) the same scheme, but with the inactivated adjuvant vaccine AS03;
3) AS03-adjuvant chimeric H8/1 intramuscular inactivated vaccine, followed by AS03-adjuvant chimeric H5/1 intramuscular inactivated vaccine.
The researchers assessed the titers of antibodies (immunoglobulins G) to epitopes H1, H2, H9 and H18), the response of plasmablasts and the level of memory B cells in peripheral blood. They found that the greatest response was caused not by a weakened live, but by an inactivated vaccine. At the same time, each vaccination scheme was accompanied by a detectable immune response.
The antibodies that appeared in the blood as a result of vaccination cross-reacted not only to the influenza virus circulating at the time of the study, but also to the subtypes of avian influenza virus and bat flu. Given the powerful immune response after a single vaccination, it can be assumed that one vaccine is enough to protect a person from a potential influenza pandemic.
This is the first fundamental study that shows that high titers of anti-stem antibodies to hemagglutinin in humans can be caused by a rationally developed vaccine, and opens up prospects for the further development of universal vaccines against the influenza virus.
According to the research group, all vaccination regimens were well tolerated by the participants, no safety problems were observed. The study will be completed at the end of 2019.
Article by D. Bernstein et al. Immunogenicity of chimeric haemagglutinin-based, universal influenza virus vaccine candidates: interim results of a randomized, placebo-controlled, phase 1 clinical trial published in the Lancet Infectious Diseases journal.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru Based on EurekAlert: Mount Sinai researchers bring us one step closer to universal influenza vaccine.