Infant and Children | July 27, 2014 | Author: The Super Pharmacist
Bacterial meningitis is a severe, highly contagious, and sometimes fatal infection of the covering of the brain called the meninges. Most cases are caused by the bacterium, Neisseria meningitidis. Neisseria meningitidis can also cause a severe infection in the blood known as septicemia.
There are five main “strains” or types of this bacterium: A, B, C, Y, and W. infection with certain strains is more common in certain parts of the world that it is in others. For instance, strains B, C, and Y cause most disease in the United States, while the B form is the most common cause of bacterial meningitis in the UK and Ireland.
In 2014, Australia approved a vaccine for the B form of the bacterium called the meningococcal B vaccine, or simply Men B. The Men B vaccine was developed by Novartis, a multinational company based in Switzerlandand, marketed under the brand name Bexsero®. While this vaccine represents a technological breakthrough that will ultimately benefit many regions of the world, many questions remain about its use in Australia.
Meningococcal B infection, just like other forms of the meningococcal bacteria, can cause severe and even deadly effects.
The two main clinical syndromes are meningitis and septicemia, which are infection of the covering on the brain and spinal cord or infection in the blood, respectively. In some cases, patients experience both clinical syndromes.
People who contract this infection often experience high fever, nausea, vomiting, headache, muscle aches, rash, and impaired concentration that generally occur rather rapidly. In severe cases, patients may experience leg pain, cold hands and feet, and changes in skin color—all of which are worrisome signs. As the infection rapidly progresses, patients may experience severe hypotension or shock.
One of the more disturbing consequences of Meningococcal B infection is that it interferes with the blood's ability to clot properly, leading to two conditions called disseminated intravascular coagulation and purpura fulminans.
Disseminated intravascular coagulation causes the patient to clot inappropriately in some regions of the body while bleeding inappropriately in others.
Purpura fulminans, which may occur in as many as one out of four people with meningococcal septicemia, is recognised by widespread bruising, bleeding, and even gangrene in the skin. Since Neisseria meningitidis is a bacterium, antibiotics can be helpful; however, even with antibiotic treatment the mortality rate from meningococcal infection is unacceptably high.
Between 3 and 15% of people with the infection die from the illness, even with antibiotic treatment. This is likely due to several reasons; patients or parents may not recognise meningitis immediately, physicians and healthcare providers may not recognise meningitis immediately, the infection progresses extremely rapidly and may be overwhelming by the time antibiotics are started, and drug-resistant strains of Neisseria meningitidis have been identified.
Since antibiotic treatment of meningococcal infection is not always successful in the consequences of the disease are so severe, prevention through vaccination is highly preferable.
The Australian Department of Health collects detailed information on infectious disease rates in the country, including vaccine-preventable diseases. The number of meningococcal infections—of all types—more than doubled in Australia between 1991 and 2001, peaking at nearly 700 cases in 2002. The steep drop in cases that occurred in 2002 was the result of a national meningococcal C vaccination program.
Meningococcal B infections are now the most common form of meningitis infection in Australia, responsible for roughly 200-250 cases each year.
In 2011, for example, meningococcal B disease was responsible for 84% of all Neisseria meningitides infections (for which the type was determined) making it the most common form of meningococcal infection in Australia. Therefore, the B form of the meningococcal bacterium is an important cause of disease in Australia.
The Men B vaccine is created using inactivated bacteria. Because it is inactivated, the vaccine does not cause disease.
As with any immunisation, there is a risk that the patient will experience pain and tenderness near the injection site and may experience fever, headache, and malaise for brief time after the injection.
In vaccine trials, the rates of serious consequences were the same in both the treatment (Men B vaccine) and control (placebo; water) groups.
While the vaccine is relatively new and long-term studies have not been performed, early results suggest that the Meningococcal B vaccine is quite safe.
It is widely accepted that paracetamol should be used following administration to reduce the potential for fever complications.
Trials of the vaccine have been extremely promising; children and teenagers have developed a strong immune response to the vaccine, which is considered an excellent result. Current estimates are that the Men B vaccine will protect against 70 to 80% of all cases of meningococcal B infection in Australia, and perhaps more. It is also unclear how long immunity will last in vaccinated patients. The ultimate effectiveness will depend on how many people receive the vaccine; however, the success of the type C meningococcal vaccine in Australia bodes extremely well for the meningococcal B vaccine.
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