Pneumonia : towards a new broad-coverage vaccine
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Published the 21.10.2017 at 20h16
Antibiotic resistance is a war. On one side, humanity. Developing antiobiotiques, she has managed, in less than a century, to drastically reduce the number of deaths due to infectious diseases. On the other, the bacteria : under pressure, they mutate and develop resistance mechanisms to antibiotics. A real arms race, where the humans have no interest to take on too much of a delay.
It is in this context that researchers from the university of Buffalo (New York) are working to develop a new vaccine against pneumonia. Responsible for the death of one million children per year (WHO, 2015), pneumonia is mainly due to a bacterium : streptococcus pneumoniae (S. pneumonia). For the time being, the available vaccines can protect against the best 23 strains of pneumococci, among the most virulent.
Wide coverage, good efficiency
But it is feared that the non-target strains come to grow, or as new strains of antibiotic resistant to make their appearance. However, the existing vaccines have limited performance. Polysaccharide vaccines (Pneumo-23, Pneumovax) have a coverage wide enough but a reduced efficiency, near-zero before the age of two years. As for the conjugate vaccines (Prevnar-13), they are more effective but their coverage is narrower (13 strains).
The new vaccine developed at the university of Buffalo, said liposome, has the vocation to combine high efficiency and wide coverage. Tested in animals, it has been able to induce a vigorous immune response on 72 pneumococcal strains.
Unlike conjugate vaccines, which need to combine each antigen targeted to a protein of portage, vaccines, liposomes, encapsulate all the antigens needed in tiny spheres (liposomes), which are capable of amplifying themselves the immune response. It is so much easier and less expensive to add new strains as and when the need arises.
“Traditional vaccines completely destroy the targeted bacteria,” says Charles H. Jones, co-author of the study. “But with this new vaccine in development, we can monitor the bacteria and attack only if they stand out of the microbiota to cause disease. This is important because leaving the bacteria are not harmful in peace, we prevent other harmful bacteria take their place. “
Remains to test and validate this prototype in man, and, in case of positive results, to industrialize its production. It will still take many years to reach an eventual finished product, but it is the hope of a new weapon in the frenzied race, which pits the man to his hosts tiny.