Latest findings can lead to the development of a vaccine to protect against common ear infection

Owwww, howls your child while holding its ear and crying. Recent findings can lead to the development of a vaccine to protect against a very common type of ear infection.

Every year, around 700 million people worldwide suffer from ear infection, many of them children. A quarter of these cases are caused by the bacterium Haemophilus influenzae (Hi). In spite of its name, this bacterium has nothing to do with influenza as the latter is caused by a virus.

'Ear infections are often painful and can in the worst case lead to impaired hearing. And there is also another very serious threat rearing its head', says Jukka Corander, professor at the Institute of Basic Medical Sciences at the University of Oslo: the high incidence of ear infections is resulting in a massive use of antibiotics.

'Ear infections are the most common reason why antibiotics are prescribed for young children. The problem is that the frequent use of antibiotics is resulting in resistance, in other words, one or more types of antibiotics no longer kill the bacteria', he explains.

A vaccine will be able to reduce the use of antibiotics

Corander and his colleagues are therefore very keen to find ways of avoiding the use of antibiotics. A key step would be to develop a universal vaccine to combat the Haemophilus bacterium. But first, Corander and his team of researchers had to carry out research on a potentially major stumbling block hindering the development of such a vaccine.

If we would uncover many different variants of the bacterium from region to region in the world, it would be more difficult to make a universally effective vaccine for use against all types of infections caused by it."

Jukka Corander, professor, Institute of Basic Medical Sciences, University of Oslo

The researchers had to find out more about Haemophilus

In order to gain a deeper understanding of the genetic variation occurring in this species, the team collected thousands of samples from both healthy and sick children over a number of years from one single area in Thailand where the rate of Hi infections is high for several reasons.

Researcher Anna Kaarina Pöntinen is the first author of the paper. She reveals that they were able to map even the finest variation in the genetic material of the species using modern DNA sequencing technology.

Vaccines are easier to develop when a bacterium does not vary from area to area

The researchers then compared these samples with thousands of samples from different parts of the world. In the new study, published in Nature Microbiology, Pöntinen presents some good news:
'Our study shows that, unlike other bacteria that are major causes of respiratory infections, there is no significant genetic variation in Haemophilus influenzae from region to region. This is good news, since if there had been many different variants, it would have been much more challenging to develop a vaccine. Our findings endorse our original hypothesis: that we can develop a universal vaccine to protect against all types of infections caused by Haemophilus', she asserts.

Funding is needed in order to develop a vaccine

Pöntinen and Corander are pleased by the findings and say they are now trying to obtain funding so that they can start work on developing a vaccine.

'We found an alarming amount of antibiotic resistance in our genetic material and were able to show that this resistance has spread around the world. This means that there is an urgent need for such a vaccine. The Haemophilus bacterium should also soon be included in a number of systems monitoring the development of antibiotic resistance. Up until now, Haemophilus influenzae has gone rather under the radar in the systems set up to monitor serious infections, but the World Health Organization WHO has recently improved the situation in its GLASS system', reveals Corander.

But he also says that there are no published reports yet after the update, so the severity of the global situation regarding multi-drug resistant Hi infections remains unknown to date.

The vaccine can also prevent pneumonia and sinus infections

The Haemophilus bacterium can also cause pneumonia, sinusitis, conjunctivitis and meningitis. Pneumonia due to the Haemophilus bacterium was the third most common cause of death amongst small children in low-income countries, as revealed by an extensive study published in 2024.

The reason why the researchers in this case are focusing on ear infections is because of their high incidence rate, which in turn imposes more selection pressure on the bacteria and generally leads to an increasing resistance to antibiotics.

Antibiotics may stop working

Anna Kaarina Pöntinen warns that if we do not stop the current overuse of antibiotics, we risk having no way of treating people when they get sick and in the future people can die of diseases that are curable today.

'With several subtypes of Haemophilus, there is now in practice only one type of antibiotic left that works. This medicine is expensive and therefore poses a problem for people who fall ill in low-income countrie's, explains Pöntinen.

Jukka Corander, who is also associate faculty at the Wellcome Sanger institute, led the study together with professor Paul Turner from Oxford University.

The study was funded by the Trond Mohn Research Foundation, the Wellcome Trust in England, the European Research Council, and the Horizon2020 program for researcher mobility.