Meningitis and Encephalitis

Maybe you’ve heard that the best way to prevent infections like encephalitis is to get vaccinated because then the bacteria and viruses that cause the infection won’t take hold. But did you know that vaccines actually cause encephalitis too? But more on that in a minute…

Meningitis and encephalitis are infections of the central nervous system. Meningitis is an infection of the meninges, part of the spinal column. Encephalitis is an infection of the brain. They can both cause serious damage or even death very quickly. But vaccinations won’t necessarily provide you the protection that the CDC has said they will.

Meningitis can be caused by bacterial, viral or even fungal infections, but vaccines target three types: pneumococcal bacteria, meningococcal bacteria, and haemophilus influenza B bacteria. There is currently a vaccine called Ixiaro for Japanese encephalitis that is licensed in the United States. Let’s take a look at some of the data for each type.

Meningococcal meningitis: The CDC has stated that the meningococcal vaccine is responsible for dramatically reducing deaths from meningococcal meningitis. The first meningitis vaccine was introduced in 1978 and was designated as the MPSV4 vaccine. In 2005 MCV4 type vaccines were introduced and are commonly used today. But what about countries where vaccination for meningococcal meningitis isn’t typically part of the vaccination schedule? Poland has kept records on meningococcal meningitis occurrence and deaths for several decades, but does not include the meningococcal vaccine as part of its schedule of vaccines and does not offer it free like other vaccines on its schedule. From 1970 to 2007, meningococcal deaths have cycled between upswings and downturns in Poland while incidence of meningococcal meningitis has remained quite consistent. Statistics show that between 1983 and 1992 there was an increase in meningococcal deaths over the previous decade, after a vaccine existed. Then in 1992, the death rate and incidence of meningococcal meningitis began to decline. In 2002, the death rate from meningitis reached a thirty year low (before the new vaccines were introduced) while the incidence of meningococcal meningitis went back up to where it was during the 1970’s stayed there. So we can see that independent of mass vaccination programs or even the existence of a vaccine, disease rates and deaths will rise and fall over the years. Who is most at risk for death from meningitis? Well Polish statistics show that while young children are more likely to contract the disease, the elderly are by far the most likely to die from it. The case fatality percentage for Polish children ages 0-19 is consistently 0-2% across all age groups, while 15% of cases in individuals aged 50-64 die from the disease and 21% of cases in individuals aged 65+ die. Just as with the flu, the elderly are most at risk because they often have underlying health issues that make them more susceptible to complications.

The National Meningitis Association reports that approximately 800- 1,200 people contract meningococcal meningitis every year and that of those around 10%-15% die and of those who survive about 1 in 5  have permanent disabilities. So taking some averages (10% death rate and 20% disability rate of 1,000 meningococcal cases), we have approximately 300 deaths or serious injuries from meningococcal disease every year. How does this stack up to the safety of vaccination? In 2013, the Vaccine Injury Compensation Program compensated 375 cases of vaccine injury or death. So you are about as likely to receive a pay out from the government for dying or being seriously injured by a vaccine as you are to die or be disabled by meningitis.

Pneumococcal meningitis: How much do vaccines impact the decrease of pneumococcal meningitis? Let’s take a look at some statistics from Europe. In Iceland, pneumococcal vaccination has been routinely administered to children since 2011. But in 1999-2000, Iceland (population 281,000 in the year 2000) saw only a single case of pneumococcal meningitis. Other countries like the Republic of Ireland (population 4 million in the year 2000) had similarly low numbers like 8 cases and Slovenia (population 1.9 million in the year 2000) had only 4. This was all before the introduction of routine vaccination for pneumococcal meningitis and represents the total number of cases, not even deaths. Other countries had bigger numbers like Italy with 76 cases and a large population of 57 million in the year 2000, while the Netherlands had the more cases (164) despite having a smaller population than Italy (15 million in the year 2000). Since there were no vaccination programs for pneumococcal meningitis in place for these countries, other factors must be influencing the rates of pneumococcal disease.

And what about the demographics of pneumococcal meningitis since the vaccine hit US markets in 2000? The pneumococcal vaccine hasn’t really eliminated pneumococcal disease, it’s just changed the epidemiology of it. Instead of babies getting the disease as used to happen quite frequently, now toddlers and school age children are contracting it.

Haemophilus Influenzae B: Haemophilus Influenzae B (Hib) is a bacteria that causes meningitis and respiratory illness, especially in young children. Health authorities say that it can cause neurological damage very quickly, even when antibiotics are administered. There have been a number of vaccines for Hib over the years, with varying degrees of efficacy and varying quality of research. The first Hib vaccine (often called PRP for its use of a polysaccharide capsule substance) was developed in 1985 and was heralded as the major step forward in meningitis prevention. Unfortunately, the vaccine was less than effective and studies found that children who had received the PRP Hib shot were actually more likely to contract Hib. (Randall Neustaedter The Vaccine Guide pg. 188). New types of vaccines utilizing conjugate proteins were developed for Hib in the early 1990’s, though in fact rates of the disease had already been declining. One study of Hib in Los Angeles declared that Hib had been eliminated from the immunized population (which they defined as children enrolled in the Southern California Kaiser Health Plan) and even stated that decline of Hib in the year before the new conjugate Hib vaccine was licensed (1990) was due to the vaccine even though it hadn’t been released yet. (Randall Neustaedter The Vaccine Guide pg. 190, summary of the study can be found here.)

How about statistics from Europe? In 1999-2000, the Republic of Ireland and the Netherlands both had routine Hib vaccination programs. However, these countries had some of the higher incidence rates of Hib. The Netherlands had 20 cases of Hib for the population, resulting in a crude incidence rate of 0.13 and the Republic of Ireland had 2 cases of Hib for the entire population resulting in a crude incidence rate of 0.06. Some countries without a routine program for Hib vaccination (like Slovenia with 14 cases for population of 1.9 million in the year 2000) did have a relatively high crude incidence rate (0.70 for Slovenia). Others like Greece and Italy had crude incidence rates of 0.04 and 0.05 respectively. The country in this chart with the lowest crude incidence of Hib was Norway at 0.02, again with no routine Hib vaccination program in place at the time. So while the Hib vaccine has been credited with declining rates of the disease, the evidence shows that it is not the cut-and-dried solution we have been led to believe.

Japanese Encephalitis: There are a few curiosities particular to the usage of the Japanese encephalitis vaccine Ixiaro in the United States. For starters, if you go across the border to Canada, guidelines are very different. According to Canadian public health officials,” No efficacy or effectiveness data exist for the Vero cell culture-derived JE vaccine, Ixiaro.” Because of this, the Japanese encephalitis vaccine is not authorized for use in children and infants in Canada. A direct quote from the Public Health Agency of Canada states”… [the Japanese encephalitis] vaccine is not authorized for use in persons less than 18 years of age due to little safety and efficacy data in this population.” In fact, public health officials in Canada warn that the Japanese encephalitis vaccine is only one part of the strategy for the prevention of Japanese encephalitis. In contrast, the Center for Disease Control in America just licensed Ixiaro for usage in children ages 2 months to 16 years on June 19, 2013. The CDC sites two cases of Japanese encephalitis that occurred in children, one of which occurred in an American child who visited the Philippines and was fatal. The other case though, was a Burmese boy who was traveling from a refugee camp in Thailand to the United States and made a complete recovery. These represented only the fifth and sixth cases of Japanese encephalitis documented in America between 1992 and 2011. (The others were adults visiting family.) The number of children who have visited Asia prior to 2013 and returned home without any further incident must be taken into account when examining the CDC’s recommendations for vaccinating children. The CDC also notes in the editorial to this report that individuals with family abroad rarely seek counsel on vaccination before traveling, and are often unvaccinated for Japanese encephalitis. The number of people who have travelled to Asia visit family between 1992 and 2011 must also be taken into account when considering the six cases of Japanese encephalitis the CDC has on record. While it is not impossible for someone who is unvaccinated to contract the disease, it is extremely rare.

Proponents of the theory that vaccination prevents encephalitis should also understand that vaccines are known to cause autoimmune encephalitis, a disease which can quickly cause disability or death. The Merck Manual Home Edition states that autoimmune encephalitis can be caused by “A virus or vaccine triggers a reaction that makes the immune system attack brain tissue (an autoimmune reaction).”

 

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