Making vaccines immune to heat
Most vaccines need to be kept cool during transport and storage, but this can be hard to accomplish. EU-funded researchers keen to tackle this healthcare challenge have developed heat-tolerant and even needle-free formulations of an HIV-1 vaccine candidate. They expect their processes to work for many other vaccines as well.
© #191404568 | Author: EdNurg, 2018 fotolia.com
Many people are unaware that even short-time exposure is enough to damage the product, says Sylvain Fleury of Swiss biotechnology company Mymetics SA. A spoiled vaccine may not work, failing to offer the expected protection and it might not actually be safe, he adds.
And yet, it is anything but rare for vaccine to be lost to this vulnerability. Cold chain breaches occur even in areas where the necessary logistics are available. They are an even greater risk in parts of the world that dont benefit from this prerequisite.
Fleury is the initiator and scientific coordinator of MACIVIVA, an EU-funded project launched to bring vaccines in from the cold. Focusing on solid formulations holds the key, according to the partners involved in this endeavour backed by the EU and the Swiss government. The project is led by Mymetics SAs Dutch sister company Mymetics BV.
The consortium is setting up pilot lines for the production of thermostable powder-based vaccines in the form of nasal sprays, oral capsules and sublingual tablets, as an alternative to heat-sensitive liquid vaccines. By the time MACIVIVA ends in November 2018, this task will be completed, Fleury reports.
The example on which the project focused is a vaccine candidate that could, one day, help to fight the AIDS epidemic. It targets HIV-1, the globally more common of the two types of HIV, Fleury notes. In addition to being more widespread than HIV-2, which is more specific to West Africa, HIV-1 is also generally more virulent, he adds.
Like most vaccines, the initial liquid formulation of this vaccine candidate had to be stored at 4 to 8 °C (no more, but no less either, to avoid damage from freezing). MACIVIVAs solid formulations of this vaccine candidate have already been shown to be stable at temperatures of up to 40 °C for at least two months, Fleury reports, and studies covering even longer time spans are planned.
A solid solution
Commercial solid-form vaccines already exist, Fleury notes. However, these products also have to be cooled, he explains.
And many of these solid powder vaccines have to be reconstituted into a liquid before use. In contrast, the powder vaccines proposed by MACIVIVA are meant to be used straight out of the box.
The candidate vaccine taken forward by the project focused is based on influenza virosomes particles derived from the membrane of dead flu viruses that can be filled or covered with substances used to treat or prevent disease.
Virosomes have no genetic material and are not infectious. They cant replicate, but they can imitate: those used by MACIVIVA are, in effect, fake viruses dressed up as HIV-1. They are deployed to prompt the immune system into producing antibodies for protection.
MACIVIVAs formulations are designed to do so where antibodies might be needed most urgently during the early stages of HIV infection, Fleury adds. Different types of immunisation a nasal spray or a pill rather than an intramuscular jab, for example could elicit immune responses of different strengths, in different parts of our body, he explains.
For HIV, it is important to induce antibodies not only in the blood, but also in the mucous membranes, where HIV-1 is likeliest to enter the body more particularly, in the genital and intestinal tract, says Fleury. Vaccine-induced mucosal antibodies could act as a front line defence.
MACIVIVAs alternative delivery forms are well suited to this purpose, Fleury adds. Connections within the immune system mean that nasal, oral and sublingual formulations can stimulate the production of mucosal antibodies in the targeted areas, he explains.
Look, no needles!
Administering MACIVIVAs powder-based products wouldnt require trained personnel. Once prescribed, vaccinations could be handled by the patients themselves, although supervision would be needed to ensure that they are carried out correctly, Fleury notes. Isolated communities without electricity in areas with patchy healthcare provision are not the only ones that would stand to benefit.
The HIV-1 vaccine candidate was developed by Mymetics prior to the project, Fleury explains. Results so far are very encouraging, he says, but trials and far more work will be required to turn it into a finished product, and funding for the next stages of the vaccines development has yet to be found.
The project has helped to take this particular vaccine forward, but this outcome, in a way, is icing on the cake. MACIVIVA focuses on the processes themselves, and it has developed solutions that could, in theory, also work for many other vaccines, Fleury notes although adjustments would be needed for every new vaccine application.
MACIVIVAs achievements build on excellent teamwork within the consortium, Fleury adds. Partners from three countries were involved, and most of them had never interacted before. We all learned a lot from each other, he concludes.