There is the possibility of developing a universal vaccine against widespread pediatric infections

Develop a universal vaccine against different strains of Haemophilus influenzaea bacterium responsible for infectious diseases in children, would solve two problems at once: it would protect children from infections and reduce the use of antibiotics, against which the bacterium is developing resistance.

Research published in Nature Microbiology found that this possibility is not that far off because, unlike other bacteria, theH. influenzae shows reduced genetic variability in the different areas of the world where it is widespread. A “stability” that will make it easier to develop a vaccine that works everywhere.

THE’H. influenzae (which, despite its name, is a bacterium and not a virus and does not cause the flu) is a bacterium that colonizes, usually harmlessly, the nose and throat. However, it can move to other parts of the body causing infections of varying severity: from the most common such as ear infections or conjunctivitis, to the most serious such as pneumonia and meningitis, for a total of approximately 200 million cases of pediatric infections of various types per year.

There are 6 types of H. influenzaeindicated by the letters from a to f and distinguishable by the polysaccharide capsules (complex carbohydrates) that cover them. The most common is type b (Hib), which can cause meningitis and against which, fortunately, there already exists a highly effective vaccine. Bacteria that do not fall into group b give rise to less serious infections, such as ear infections, bronchitis or sinusitis, but are still responsible for a good portion of total infections, around 175 million cases per year, against which antibiotics are often used.

A collaboration of scientists from the Wellcome Sanger Institute (UK), the University of Oslo (Norway), the University of Oxford (UK) and Mahidol University in Thailand has carried out the first large-scale genomic sequencing study of samples of the bacterium collected anywhere in the world between 1962 and 2023, thus reconstructing a global picture of how the pathogen evolved and presents itself.

After studying nearly 10,000 samples of H. influenzaethe team concluded that the bacterium, unlike many other major respiratory pathogens, did not evolve regionally specific lineages. And that, despite having a marked tendency towards genetic recombination (i.e. the exchange of genetic material between different bacteria during reproduction), these genetic variations are constantly removed by natural selection, because the bacterium as a whole presents very low genetic variability.

This is excellent news because, as Anna Pöntinen, a biostatistician at the University of Oslo who co-signed the study, explains, «if there had been many different local variants, it would have been much more difficult to develop a vaccine. The results confirm our original hypothesis: it is possible to develop a universal vaccine to protect against all types of infections caused by Haemophilus». Reducing global dependence on broad-spectrum antibiotics.