Meningococcus – symptoms, treatment, meningococcal vaccine

The example of several spectacular local menigococcal epidemics in our country in recent years clearly shows how dangerous the infections caused by meningococcus are. Within a dozen or so hours after infection, the disease may develop dramatically and end in death. Mortality is around 10-15%, but can be as high as 80% in the case of septic shock.

Meningococcal infections

Epidemiological reports of the National Institute of Hygiene indicate an increase in the incidence of invasive meningococcal disease and the emergence of meningococcal strains with increased virulence. In 2009, there were 296 cases of the disease, almost half of which concerned children under 4 years of age. Unfortunately, most of these cases took the form of sepsis. Based on the analyzes, the incidence of meningococcal disease ranges from 1-3 per 100 inhabitants.

The optimistic thing about meningococcal infection is that these bacteria are fortunately relatively low-transmissible, so that in most cases of exposure to bacteria, infection and disease do not develop.

See also: Infectious diseases of childhood

An image of the meningococcus

Neisseria meningitidis, or meningococci, belong to the gram-negative pathogenic bacteria of a grain-like shape, which is why they are often also referred to as meningitis.

A characteristic feature of bacteria is that they have an outer shell made of various types of sugars. This diversity makes it possible to distinguish 13 serogroups of bacteria, among which serotypes A, B, C, Y and W135 cause the majority of cases of disease. The distribution of serotypes varies around the world and this information is important when prophylactic vaccinations are used before traveling to epidemic regions.

In Poland, serotype B is dominant and the share of serotype C is increasing, while serotype A is responsible for causing large epidemics in sub-Saharan Africa.

Type B strains of meningococci are mostly sporadic and less virulent in most cases, while epidemics are mainly caused by C strains, which have a high potential of virulence leading to sepsis.

Only humans are the natural reservoir of meningococcus, and these bacteria colonize the nasopharynx, causing asymptomatic carriage. The phenomenon of meningococcal carrier in the population is estimated at 2-20% and the highest percentage of carriers occurs in the age range of 15-24 yearswhile in closed communities, e.g. military barracks, prisons, kindergartens, dormitories or orphanages, carriage may reach even 40-70%.

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Meningococci – pathways of infection

Meningococcal infections most often affect children up to 5 years of age, and the highest number of infections is reported in the group of children up to 1 year of age. The second group where an increased number of infections is observed are adolescents and young adults.

Infection occurs through droplets or direct contact (coughing, sneezing, kissing, sharing a glass, etc.)

Meningococcal infections are characterized by a seasonal nature of their occurrence and in Poland the most cases are observed in the first months of the year.

In Poland, there are between 300 and 500 cases of ICHM (invasive meningococcal disease) every year, which shows that the number of cases is not high, but one should bear in mind how severe the disease is and how dangerous it is for the patient’s life. All this means that the possibility of prophylaxis through protective vaccinations should be taken seriously.

It should be remembered that meningococcus is more common in children and adults who have had close contact with people with invasive meningococcal disease (eg the risk of infection of a child whose co-home mate is 500–800 times higher than the average).

Meningococci – symptoms of infection

The incubation period of invasive meningococcal disease is on average 3-4 days.

Symptoms of infection can vary. The disease usually begins suddenly with fever, muscle aches and sometimes vomiting. After 4-6 hours, a temporary improvement may occur (temperature drop, symptoms disappearance), but then the clinical condition deteriorates. Depending on the form, symptoms of meningitis may appear: headache, convulsions, high fever, disturbed consciousness or symptoms of sepsis, the characteristic symptom of which is a hemorrhagic rash, usually beginning on the lower limbs.

The occurrence of a hemorrhagic rash in the course of fever should always raise alertness, and this fact should be an urgent cause for medical consultation. Additional symptoms of sepsis are also: rapid breathing, increased heart rate, high fever and progressive deterioration of the general condition. It should be emphasized that meningitis can progress to sepsis.

Meningococcal infections can take the form of:

1) invasive meningococcal disease – it is a severe systemic infection and we distinguish here:

1. meningitis
2. sepsis
3. Waterhouse-Friderchisen syndrome – fulminant sepsis with adrenal hemorrhagic necrosis
4. pneumonia with bacteremia
5. inflammation of the heart muscle, endocarditis or pericarditis
6. septic arthritis
7. bone marrow inflammation

2) non-invasive infections (rarely) such as:

1. conjunctivitis,
2. sinusitis,
3. otitis media.

The prognosis for people with invasive meningococcal disease is poor. In the absence of early diagnosis, early antibiotic therapy and intensive medical care, the mortality rate reaches 70%. Permanent complications of the disease include: hearing impairment, neurological disorders (epilepsy, memory impairment), bone and joint damage, loss of fingers due to necrotic changes, and kidney damage.

Meningococci are not very contagious, and as a result, infection occurs only as a result of very close contact with the carrier, less often with the sick person.

It is worth noting that both meningococcal sepsis and meningococcal meningitis have a high risk of death. According to KOROUN data, in 2018 the overall death rate was 17,9%. In the case of seniors (over 65), it amounted to as much as 28,5%, and in children up to the age of 1, 15,8% 1.

Meningococcal – diagnosis and treatment of meningococcal infections

The diagnosis of the disease should be made as soon as possible, as it significantly improves the prognosis. The basis of diagnosis is the cultivation of meningococcus from blood, cerebrospinal fluid or a nasopharyngeal swab.

Suspicion of invasive meningococcal disease is an indication for urgent hospitalization – very often in intensive care units, and urgent and as soon as possible intravenous antibiotic therapy. The treatment mainly involves penicillin or third-generation cephalosporin antibiotics.

Meningococci – prophylaxis

Vaccination is the most recommended way to protect against meningococcus.

Due to the diversity of the bacterial serotypes, monovalent (containing one type) and polyvalent (containing several types) vaccines are available.

In Poland, a polyvalent vaccine against serotypes A + C (Meningo A + C Sanofi Pasteur) and monovalent vaccines against serotypes C (Neisvac-C Baxter and Meningitec Wyeth) are registered.

The available vaccine against serotypes A and C is an unconjugated polysaccharide vaccine and is recommended from the age of 2 during epidemics and when traveling to areas with high risk of developing meningococcal disease, mainly serotype A. This vaccine is characterized by a good, but short-term (approx. 5 years) with immunological protection.

Vaccines against serotype C are conjugate vaccines and can already be used in children over 2 months of age. These vaccines provide long-term immunity. The number of doses of the vaccine depends on the age at which vaccination begins: in children over 1 year of age, in adolescents and adults, one dose is sufficient, while in children under 1 year of age it is advisable to give 2 doses of the vaccine with an interval of 2 months and a booster dose in 2 months. age.

Vaccines are especially recommended for people at risk of:

1. children from 2 months to 6 years of age
2. adolescents from 11 to 24 years of age
3. people at risk of falling ill as a result of direct, permanent contact (e.g. nursery, kindergarten, soldiers, students, people traveling to endemic and epidemic regions).

Unfortunately, there is no universal vaccine against type B strains, and this is due to the similarity of the envelope sugars to human molecules and therefore does not generate an immune response in our body. Work is currently underway to develop a vaccine against B based on the use of genetic methods.

The second way to protect against meningococcal infection is called chemoprophylaxis, which consists in administering most often one dose of an antibiotic acting on meningococcus to people who have direct contact with the sick person.

Chemoprophylaxis is recommended for people who had close contact (they stayed at least 4 hours a day in the same room) or very close (even short-term – e.g. kissing, using the same toothbrush, eating from the same dishes or using the same cutlery) ) with an invasive meningococcal disease 7 days before the onset of the disease. Prophylaxis should be given preferably within 24 hours of contact, and up to a week after contact.

In chemoprophylaxis, it is recommended to administer one of the drugs:

1. rifampicin for 2 days orally,
2. ceftriaxone – once intramuscularly,
3. ciprofloxacin – once orally, but only in people over 18 years of age.

In addition, all contact persons are also recommended to be vaccinated against meningococci as soon as possible.

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The effectiveness of vaccination against meningococcus

Meningococcal vaccines are effective in stimulating the immune system. Almost all children develop protective levels of antibodies at the end of the vaccination course. It is also worth adding that Post-vaccination immunity in children from 1 year of age, adolescents and adults is likely to persist for a long time, as well as in adolescents and adults. In infants vaccinated at 1 year of age, the level of protection gradually decreases and a booster dose of vaccine is required by 2 years of age.

While vaccination has not been investigated to reduce the individual risk of a child falling ill, in countries where vaccination of children with conjugate vaccines has become widespread, a significant reduction in invasive meningococcal disease has been observed. It should also be mentioned that meningococcal vaccines are effective in preventing meningococcal accumulation in the throat (ie carrier) and thus reducing the risk of infection to other people.

Safety of meningococcal vaccines

It should be mentioned that meningococcal vaccination is safe and the risk of serious reactions is low, as is the case with other commonly used vaccines.

Very rarely, but minor local reactions may occur, such as: tenderness and pain at the injection site or redness. There may also be general reactions, including: decreased appetite, irritability and sleep disturbances. They occur in about 10 percent of vaccinated people. Even less frequently (1–10%) the following occurs: vomiting, fever, pain in muscles and limbs. These symptoms are short-lived and go away on their own.

More often than with conjugate vaccines, reactions such as fever or pain at the vaccination site are observed when vaccinated with the menigococcal B protein vaccine. This is especially true when used simultaneously with other vaccines.

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When should I get the meningococcal vaccine?

It is best to start the meningococcal vaccination in the first or second year of life. In the first case, after vaccination, the level of protective antibodies will gradually decrease, which means that a booster dose should be given after the age of 12 months.

With age, the risk of developing meningococcal disease decreases, but the disease can also occur in older people and is then burdened with the highest mortality rate, exceeding 30%. This ensures that it is never too late to be vaccinated.

If you have not had a meningococcal vaccination at a young age, it is no problem to get vaccinated at a later age, especially in older children, adolescents and young adults. The vaccines are given by injection into a muscle. Importantly, they can be administered simultaneously with most other vaccines.

Meningococci – booster vaccination

In the case of meningococci, the vaccine immune memory that makes the body’s immune system recognize the enemy and produces antibodies turns out to be insufficient. The meningococcal vaccine given to infants may not be effective during adolescence. These bacteria attack quickly. Therefore, the antibody concentration must be maintained continuously for some time after vaccination to ensure adequate protection.

Due to the speed of the meningococcus, there is a risk that the sick person will die before their body can make antibodies. This gave rise to the idea that babies vaccinated against meningococcus during infancy should receive a booster dose of vaccines during adolescence to ensure that sufficient antibody levels are maintained to stop the disease from progressing.

Experts: the vaccine is an effective defense against meningococcal C group

Is there a fee for meningococcal vaccination?

Vaccination against meningococcus belongs to the group of recommended vaccinations and is payable.

There is a free option when an epidemic occurs, then the sanitary and epidemiological authorities carry out ad hoc vaccination campaigns in environments of the highest risk at the expense of the state. It is also worth mentioning that some local governments also carry out free vaccinations.

Find out more: Mandatory and recommended vaccinations – how much does it cost?

Is meningococcal vaccination mandatory?

In Poland, there is no obligation to vaccinate against Neisseria meningitisalthough it is recommended. It should be remembered that although meningococcal disease is often undiagnosed, due to its course, it can end tragically. Therefore, it is worth taking care of protecting yourself and your relatives against meningococcus and taking advantage of the possibility of preventive vaccination.

Find out more: Recommended vaccinations – is it worth it?

Meningococci are pneumococci

Sometimes meningococci are confused with pneumococci and are treated as a single pathogen. However, this is a misconception because these bacteria belong to completely different species. In the case of pneumococci, they belong to the species named Streptococcus pneumoniae and the gram-positive group, and meningococcus belongs to the species Neisseria meningitidis and gram-negative group. In addition, when using Gram staining, these bacteria differ in color, which is due to the different structure of the cell wall.

More importantly, both species cause different diseases. In the case of pneumococci, they are responsible for pneumonia and invasive pneumococcal disease, and in the case of meningococci, they mostly cause a very specific rash, meningitis, and sepsis. From the legal point of view, in the case of pneumococci, compulsory (reimbursed) preventive vaccinations have been performed on children in Poland since 2017, and in the case of meningococci, protective vaccinations are only recommended (payment obligation) by the Ministry of Health.

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