Flu super vaccine is successful in the 1st phase of testing – 04/27/2023 – Health

The search for a vaccine against the influenza virus, which causes the flu, which is highly effective and can be used against all types of the virus has been the focus of research by several groups of scientists for years.

One of the main problems in the development of a universal vaccine candidate is that, every year, the strain of influenza in circulation changes, making the immunizer used in people each season outdated in relation to the new strain.

Therefore, researchers from the National Institute of Allergy and Infectious Diseases (NIAID), linked to the US National Institutes of Health, and the Icahn School of Medicine at Mount Sinai Hospital, in New York, developed what they call a “super vaccine”, capable of producing antibodies against a wide range of forms of the influenza virus.

Using the technology known as nanoparticles —lipid particles containing proteins or parts of the virus against which it is desired to produce antibodies—, the scientists arrived at a set of two formulations to evaluate the safety and immune response of a vaccine against influenza A capable of protecting also against other strains.

The secret for the new vaccine is in the hemagglutinin, the letter “H” of the types of influenza (H1N1, H5N1, H3N8 etc). It is the main protein that binds the virus to host cells.

Hemagglutinin (or HA) is the target of the virus against which vaccines normally seek to induce an immune response, since it is its binding to cells that can lead to infection. The problem with already licensed flu vaccines is that they seek a defense against the “head” of the hemagglutinin (which is shaped like a hat), which has a considerable variable in terms of the strains in circulation, making the immunity produced in the season past is no longer effective with the circulation of new strains.

The research published in the journal Science Translational Medicine last Wednesday (19) sought to induce an immune response against the “body” (or stem) of the hemagglutinin based on the protein obtained from influenza A type H1. Scientists saw that this protection was conserved and lasted for more than a year after vaccination.

“Influenza still causes more than 52,000 deaths per year in the US, and about 400,000 deaths per year. Therefore, constantly updated flu vaccines must be ‘customized’ to target the changing virus,” the authors wrote in the article. .

As the central part of the hemagglutinin is conserved in the different types of influenza, the vaccine also produced a memory immune response against the other viruses. According to a second experiment carried out by the researchers, type B defense cells (which produce antibodies when a pathogen comes into contact with the organism) induced the production of neutralizing antibodies against different parts of the virus, thus suggesting a “universal” protective response “.

“The main protective response focused on the central hemagglutinin region, but we also observed that the antibodies had neutralizing action against a wide range of influenza type 1 virus subtypes,” said Karin Bok, director of NIAID’s vaccine research group, and current head of the agency’s Pandemic and Emergencies Response and Prevention.

The research consisted of a phase 1 clinical trial, when seeking to evaluate the safety and immune response of the vaccine, in 52 healthy adults from April 2019 to March 2020. Initially, the study included vaccinating all individuals with a dose and a booster after four months, but only 35 showed up to receive the booster due to Covid restrictions in early 2020.

According to Bok, this is the first clinical study that sought to understand the role of specific antigen against the hemagglutinin stem. “We are in the process of studying in detail the immune response resulting from the administration of this vaccine in humans, including defense T cell responses”, she said, in an interview with Sheet.

The immune response generated by T cells, or lymphocytes, usually comes later in the immune process, and is specialized in attacking cells infected with the virus.

With the new technologies that have come with the development of Covid vaccines, researchers hope it will not be difficult to produce the flu vaccine candidate at scale.

“This nanoparticle-based vaccine technology is not yet used in any vaccine currently approved in the US. The prototype is the first of its kind to use a ferritin [adjuvante] as a support to present specific antigens against influenza”, said the researcher.

“The production of this vaccine could be easily replicated by immunization factories with the capacity to manufacture proteins or mRNA technology”, he added.