Spray or patch, the search for further vaccines useful against Covid-19 knows no crisis. Because if we already have extremely safe and effective products on the market, there are numerous attempts to develop vaccines that can further improve the fight against the virus. Having more vaccines available is essential in dealing with Sars-Cov-2: from stimulating “different components” of the immune system to greater ease of administration, vaccination research has never been as buzzing as with this pandemic.
To beat Omicron, new vaccines are needed. And poor countries must be immunized
by Antonio Cassone
MRNA vaccines
The goal of vaccination, whatever it is, is to provide our body with an image – as truthful as possible – of the infectious agent causing the disease. The advantage is simple: not having to administer the virus in its entirety, what is obtained is the same immune response that would be generated by encountering the infectious agent in its entirety without developing the disease. With those based on mRNA, the vaccines available today in our country, what is supplied to our cells is the only information necessary to produce the spike protein, a decidedly reduced portion compared to the intact virus. Once produced, it is recognized by the immune system just like the virus. An innovative strategy – but with regard to the fight against cancer, the mRNA approach has been underway for many years – which is making it possible to avoid thousands of deaths from Covid-19.
Modern, booster increases antibodies against Omicron 37 times
… and those using the “classic” method
However, alongside mRNA technology, the administration of Nuvaxovid, the Novavax “protein” vaccine, has recently been started in Europe. In this case the final goal is always the same, what changes is the way in which the immune system is stimulated. To do this, however, the US company used a different method, very common for other types of subunit vaccines: first, a portion of DNA containing the information necessary to produce the spike protein was inserted inside a “baculovirus” .
Subsequently in vitro some cells that act as reservoirs are infected with the virus. Once inside, the baculovirus releases the genetic material useful for the production of the spike. This, as with viral vector vaccines, is produced and then released outside the cell. Once a sufficient amount of spike protein is obtained, this is extracted, purified and compacted giving rise to viral nanoparticles containing up to 14 spikes. These particles, added to an adjuvant molecule capable of stimulating the immune system, are thus ready to be injected.
Novavax vaccine, Ema’s ok
The T-cell patch
But when our body comes into contact with a harmful external agent such as Sars-Cov-2, it produces an immune reaction consisting of two phases: the non-specific one – already present at birth and not dependent on previous encounters – and the specific one, directed precisely. against that particular external agent. The latter is essentially mediated by two types of cells: B lymphocytes and T lymphocytes. The former are responsible for the production of antibodies, the latter for the cellular response to the virus. In both cases, following an infection or vaccination, specific memory cells are created that are able to be activated in the event of an encounter with the pathogen.
As for the vaccines on the market today against Covid-19, the main response that is triggered is the antibody one. And it is precisely for this reason that we are trying to understand how to massively activate the response to T cells. Like antibodies, in the genesis of long-term immunity, there is the response mediated by T cells. in fact, unlike the B responsible for the production of antibodies, they have the precise task of recognizing the cells infected by the virus.
To better stimulate the T-cell response, researchers from British biotech Emergex are working to develop a vaccine with this function. The underlying mechanism is completely different from the vaccines used today against Sars-Cov-2. To be administered, by means of a patch with micro-needles, will be synthetic molecules that mimic some viral proteins capable of specifically stimulating only T cells. The experiment will begin on January 3 on 26 volunteers.
A spray vaccine against Covid
by Aureliano Stingi
The vaccine as a nasal spray
Looking closely at the different actors of the immune response, saying “antibodies” does not account for the complexity of the immune response. Vaccines administered intramuscularly have proved particularly useful in inducing the production of neutralizing IgG, IgM and serum IgA (in the blood). However, what is being observed is a reduced neutralization of the virus at the level of the respiratory mucous membranes, this explains why even vaccinated people – albeit to a much lesser extent – can transmit the virus. For this reason, vaccines capable of stimulating the IgA response at the level of the mucous membranes are being studied. As? By administering the vaccine through a nasal spray. At present, experiments in animal models would seem to indicate the goodness of this approach. However, there is still a long way to go. But be careful to think that all these “alternative” approaches are in contrast with the vaccinations available today. If and when these vaccines see the light, the goal is not at all to add new products against Covid-19 but to provide useful tools to further improve immunity in the long term.
Covid: so it changed us forever
by Daniela Minerva
.