The dangers of meningococci
Meningococci can cause serious infections, including meningitis, which is an inflammation of the membranes surrounding the brain and spinal cord. These bacteria of the Neisseria meningitidis genus are responsible for around a quarter of bacterial meningitis in France, but they can also cause other serious invasive infections, such as blood infections.
In France, meningococci caused 560 cases of invasive infections in 2023, an increase of 72% compared to 2022. There are several groups of meningococci, the most virulent of which are groups A, B, C, W, , and Y, which can cause epidemics, particularly in children and young adults.
How are meningococci transmitted?
Meningococci are transmitted mainly through close contact with a person carrying the bacteria, often via droplets of saliva emitted when coughing, sneezing, or kissing. Approximately 10% of the population, particularly adolescents and young adults, are healthy carriers of these bacteriathat is, they harbor them in their throat or nose without developing symptoms.
The danger arises when, under certain conditions, the bacteria crosses the mucous membrane of the nose and enters the blood, where it can trigger serious infections such as meningitis or septicemia.
What are the symptoms of these diseases caused by meningococci?
Invasive meningococcal infections are serious illnesses that can affect anyone, but they particularly strike young children, adolescents, young adults, the elderly, and immunocompromised individuals.
Among these infections, meningitis is one of the most commonmanifested by typical symptoms such as high fever, neck stiffness, severe headache, nausea, vomiting and increased sensitivity to light. However, symptoms can vary, especially in very young children or the elderly.
Furthermore, meningococcal septicemia is a generalized infection where the bacteria spreads through the blood and affects various organs. The most severe form of this infection is purpura fulminans, which can lead to a rapid deterioration in health and is manifested by the appearance of red or purplish spots on the skin.
Invasive meningococcal infections are life-threatening emergencies which require immediate treatment. They can lead to a rapid deterioration of the general condition and cause serious complications, even fatal, if they are not treated without delay. Faced with such symptoms, it is crucial to immediately contact 15 or consult your doctor to receive emergency treatment.
Different vaccines to protect against meningococci
There are three main types of vaccines to protect against invasive meningococcal infections.
• The first is a vaccine targeting only group C meningococcushistorically administered routinely to babies (Neisvac® or Menjugate®).
• The second vaccine is intended to prevent infections caused by group B meningococcuswhich remains one of the main causes of serious bacterial meningitis, particularly in young children. Until now, this vaccine, known as Bexsero®, was recommended but not obligatory for babies aged 3 months and over.
• Finally, the third type of vaccine (Nimenrix®, Menquadfi™ or Menveo®) offers protection against four groups of meningococci (A, C, W, and Y)which, until now, were not included in routine vaccination recommendations for the general population in France.
New recommendations for vaccination against meningococci
For vaccination against meningococci groups A, C, W and Y
The new recommendations for vaccination against meningococci in France aim to respond to the evolving health threats posed by these bacteria. After a lull observed during the pandemic thanks to barrier gestures, the data collected in 2022/2023 show an active resumption of the circulation of meningococci in the country.
While invasive infections linked to group C meningococcus have become rarer, largely thanks to compulsory vaccination of babies, a worrying increase in infections linked to groups W and Y has been noted. These strains, particularly group W, were found to be very virulent, with an increased risk of mortality.
To respond to this new threat, the vaccine which only protected against group C meningococcus will be replaced by a vaccine (1) also covering groups A, W and Y, thus becoming compulsory for all babies under one year old. . This decision aims to expand the protection of young people against these dangerous strains which, until now, have not been systematically targeted by routine vaccination. The new recommendations indicate that for infants who have already received a first dose of meningococcal C vaccine, it is possible to continue the vaccination schedule by administering the ACWY vaccine for the booster, instead of the second dose initially planned against group C . It is therefore not necessary to start the entire vaccination schedule from the beginning.
Vaccination against meningococci A, C, W and Y is extended to adolescents aged 11 to 14, whether or not they were vaccinated against type C when they were babies, with the possibility of catch-up for young adults up to ‘at 24 years old.
As for children aged 1 to 10 years, it is not necessary to vaccinate them outside of the protocols already in place, except in special circumstances (immunocompromised children, etc.).
By adapting the vaccination protocol, health authorities hope to slow the spread of these meningococci and reduce the number of serious cases, particularly among infants, who are particularly vulnerable to these infections.
For vaccination against meningococcus group B
The vaccine, previously recommended but not obligatory, will become obligatory for all babies from January 2025 (1). This decision was taken by health authorities to strengthen protection against meningococci B, which are the main cause of invasive infections and meningitis, particularly in infants and very young children.
Although adolescents and young adults aged 15 to 24 are more affected than the rest of the population, they are less affected by group B meningococcus than children under 5 years old. This is why health authorities have not deemed it necessary to recommend vaccination of all adolescents against meningococcus Bunlike types W and Y. However, the High Authority of Health proposes that vaccination against meningococcus B be reimbursed for young people aged 15 to 24 who still wish to be vaccinated.
What about adults over 25?
For those outside the age groups mentioned above, vaccination is not systematically recommended. However, it can be considered in high risk situationsas for immunocompromised people, those exercising high-risk professions (such as laboratory researchers working on meningitis), travelers going to regions where meningococci are actively circulating, or even for those who have been in close contact with people with invasive meningococcal infection. In these cases, it is advisable to contact your doctor to determine whether vaccination is necessary.
(1) A decree is being prepared to set the date of entry into force (which should be January 1, 2025) of the new vaccination obligations recommended by the High Authority for Health.
