Sunday, November 16, 2008

Pneumococcal Meningitis Information

In the weeks and months that followed Abby's death, I devoted almost every moment of the day to researching Pneumococcal Meningitis. Here is a brief overview of the facts:

· What is meningitis?

o It is the inflammation of the membranes (called meninges) surrounding the brain and spinal cord. It can be caused by a number of viruses, bacteria, or fungi.

· What are the common types of bacteria that can cause meningitis and what vaccines are available?

o Haemophilus influenza type b- You don’t hear about this one too much anymore because children now receive an effective vaccine for Hib

o Neisseria meningitides – This is more commonly known as Meningococcal Meningitis. There are two vaccines that older children and adults can receive for some (but not all) of the strains: Memomune and MenactraT. If you have heard of meningitis outbreaks, this is the type that is usually involved. Anyone in contact with the infected person is usually given antibiotics as a precaution. There is an increased risk for college students living in dorms or military members living in barracks; essentially any group of people living in close quarters. Sub-Saharan Africa is sometimes referred to as the Meningitis Belt, as large epidemics usually occur during the dry season.

o Steptococcus pneumoniae- This is more commonly known as Pneumococcal Meningitis. There are presently 91 strains of this bacteria and Prevnar, a pneumococcal conjugate vaccine, has been available since the year 2000. It covers 7 strains: 4, 6B, 9V, 14, 18C, 19F, 23F. Wyeth, the maker of Prevnar is working on a new conjugate vaccine that will cover 6 additional strains: 1, 3, 5, 6A, 7F, 19A. There is also a pneumococcal polysaccharide vaccine, Pneumovax 23, which is not effective in infants, but given routinely to adults. It covers 23 strains: 1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F, 33F. Abby died from a strain not covered by any of the vaccines. She received all 4 of her Prevnar vaccine shots; however, protection against one strain does not offer any protection against another.

· How do people get the bacteria that cause meningitis?

o I can only speak for s. pneumoniae. It is a common bacterium that lives in the nasopharynx of up to 25% of the population. That number can increase to 40% in children. The bacteria can spread through the exchange of respiratory or throat secretions. Having the bacteria doesn’t mean that one will get sick. Pneumococcal infections can invade the lungs and cause pneumonia, invade the bloodstream and cause bacteremia, invade the sinuses and cause sinusitis, invade the ears and cause otitis media (middle ear infection), or invade the covering the brain and cause meningitis.

· Who is at risk for pneumococcal infection?

o Alaskan natives, American Indians, persons aged 65 and older, individuals with a weakened immune system, individuals without a functioning spleen, alcoholics, and children in large day-care centers. I have also read studies indicating that it is more common in males, children who were never breastfed, smokers, and more common during the winter months. For reference though, my daughter did not meet a single one of these increased risk factors.

· What are the symptoms of meningitis?

o Again, only speaking for pneumococcal meningitis. In persons over age 2, common symptoms are high fever, severe headache, stiff neck, vomiting, sensitivity to light, and in some cases, bruising and seizures.

o In infants, common symptoms are fever, vomiting, poor feeding, lethargy, and in some cases bruising and seizures.

· How is meningitis diagnosed and what is the treatment?

o A spinal tap (lumbar puncture) will be performed to take a collection of spinal fluid and grow bacteria from a sample.

o Treatment includes a number of antibiotics administered intravenously. A lengthy hospital stay is usually required for those that survive this disease. Due to the speed with which the bacteria multiply once in the bloodstream, a person can go from asymptomatic to critically ill within hours.

· What are some of the complications from meningitis?

o Death, brain damage, coma, hearing loss, mental retardation, paralysis, and seizures.

· How common are pneumococcal infections?

o Annually in the US, there are about 175,000 cases of pneumonia; 50,000 cases for bacteremia; and 3,000-6,000 cases of meningitis. According to the CDC, there are around 6,000 deaths annually from invasive pneumococcal infection (source: National Foundation for Infectious Diseases)

· What is the future development of vaccination?

o Wyeth is making progress on a pneumococcal conjugate 13-valent vaccine. It will cover 6 additional strains of the vaccine that the existing Prevnar (PCV-7 valent) vaccine does not cover. The original 7 strains (serotypes) were selected because they were the most common cause of invasive pneumococcal disease. The next 6 strains to be included are now becoming more common (This is called The Replacement Effect – e.g. now that the 7 most common have been taken out of the population due to the vaccine) and some have been found to be antibiotic-resistant. Additionally, work is being done to develop a vaccine that will cover all 91 strains. This work effort is being led by Dr. Richard Malley of Children’s Hospital of Boston. My opinion: bacteria have been around for millions of years. As smart as we think we are, bacteria continue to evolve and sadly, will never be eliminated.

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