Meningitis, meningococcal disease, and vaccines

SciMoms recently shared the story of Patti and Alicia, parents whose teenage children passed away from Meningitis B. These moms founded the Meningitis B Action Project  to share their personal stories and raise awareness about an often overlooked vaccine: the MenB vaccine. Their brave act led me to realize how little I know about bacterial meningitis and meningococcal disease. In this post, I’ll take a closer look at the disease and which vaccines can prevent various causes of meningitis. 

What is meningitis?

Meningitis is the swelling of the protective tissue that surrounds the brain and spinal cord (the meninges). Meningitis can be infectious and caused by viruses, bacteria, fungi, or parasites. Some meningitis is non-infectious and caused by cancers, lupus, certain drugs, head injuries, or brain surgery. In this post, we will focus on viral and bacterial meningitis and the vaccines that can prevent them.

What is viral meningitis?

Viral meningitis (meningitis caused by a virus) is the most common form of meningitis. Thankfully, most people recover on their own. However, anyone with symptoms of meningitis should see a doctor right away to rule out other causes that can be treated and to make sure it is not a serious case. 

Symptoms of viral meningitis in babies include: fever, irritability, poor eating, sleepiness, lack of energy, or trouble waking up. In children and adults, additional symptoms include headache, stiff neck, eye sensitivity to light (photophobia), nausea, irritability, vomiting, and lack of appetite.

Children under five and people with weakened immune systems have a higher risk of getting these diseases. Babies under one and people with weakened immune systems are also at risk to have more severe illness.

The most common causes of viral meningitis are non-polio enteroviruses. Other viruses that can cause meningitis are mumps virus, measles virus, influenza virus, West Nile virus, lymphocytic choriomeningitis virus, and herpes viruses that include Epstein-Barr, herpes simplex, and the varicella-zoster virus that causes chickenpox and shingles. These viruses are contagious and can spread from person-to-person. Fortunately, most people who are infected with these viruses do not develop meningitis.

What is bacterial meningitis?

Bacterial meningitis is caused by bacteria. While the initial symptoms of viral and bacterial meningitis are similar, bacterial meningitis is unique because of the speed in which it can quickly impact an individual. The CDC highlights that “death can occur in as little as a few hours.” Most people recover from bacterial meningitis, but it can lead to long term damage, including hearing loss and brain damage. The bacteria that cause bacterial meningitis are also associated with sepsis. Sepsis is an extreme reaction to severe infection where the body starts fighting against itself leading to organ damage or failure or death. Because of the speed and potential severity, it is critical that anyone with symptoms of meningitis see a doctor immediately.

Symptoms of bacterial meningitis include flu-like symptoms that start suddenly and worsen very quickly. The most common symptoms are fever, headache, and a stiff neck. Other symptoms may include eye sensitivity to light (photophobia), nausea, vomiting, or confusion. It can be difficult to identify these symptoms in babies, so watch for slow or inactive behavior, irritability, vomiting, feeding poorly, or a bulge in the soft spots of their skull. Symptoms typically develop three to seven days after exposure. CDC recommends seeking medical attention immediately if you or your child develops these symptoms. 

Bacterial meningitis can be caused by multiple types of bacteria. The risk factors and who is most susceptible depend on the specific bacteria.

  • Streptococcus pneumoniae: children, particularly under the age of five, are at high risk from these bacteria, which are most often transmitted by coughing or sneezing to close contacts. 
  • Group B Streptococcus: Mothers can pass this bacteria during childbirth, and this can lead to meningitis in infants.
  • Haemophilus influenzae: These bacteria are primarily spread by coughing and sneezing to close contacts and infants and children are most at risk of infection. 
  • Listeria monocytogenes: These bacteria can cause listeriosis and are primarily transmitted via contaminated food. Pregnant women, newborns, or individuals with weakened immune systems are most at risk of contracting listeriosis. While listeriosis is generally mild in pregnant women, it can cause severe problems to a fetus or newborn.
  • Neisseria meningitidis: These bacteria can cause meningococcal disease, which we review in more detail in the next section.

(Post continues after infographic)

Infographic: SciMoms guide to meningitis and meningococcal disease. Causes of meningitis. Definition of meningococcal disease. Meningococcal vaccines.

What is meningococcal disease?

Meningococcal disease are illnesses caused by the bacteria Neisseria meningitidis, also called meningococcus. There are five subtypes, known as serotypes, of meningococcus.

When we hear about “bacterial meningitis” in the news or media, it is usually referring to meningococcal disease. This is because of the speed at which this disease can kill young, otherwise healthy, adults. 

Meningococcal infections are fairly common, with 1-10% of the population carrying the bacteria in their throats (this may be higher during an epidemic).  In some people, infection with meningococcus can be serious and deadly if the infection spreads to the brain (causing meningitis) or blood (bacteremia or septicemia). Symptoms of meningococcal disease that has spread to the brain and caused meningitis are the same as those listed above for bacterial meningitis. In the United States, the frequency of these infections is 0.11 per 100,000 individuals, representing approximately 350 cases per year. 

In many cases, taking antibiotics in time can prevent the worsening of infection and the onset of meningitis. However, the World Health Organization highlights that meningococcal disease is lethal in 8-15% of cases even when treatment is given in time, and death often occurs within 1-2 days after symptoms first appear. If not treated, it is “fatal in 50% of cases and may result in brain damage, hearing loss or disability in 10% to 20% of survivors.”

Meningococcus spreads between people who are in close contact for prolonged periods through respiratory droplets or throat secretions. It spreads through smoking, kissing, sneezing, coughing, or living in close contact. Consequently, infection is more common among those living in close quarters, like dorms and barracks, and in mass gatherings. In the US, this is why we often hear about bacterial meningitis outbreaks in groups of college students and young adults.

Meningococcal disease also occurs in infants and is a significant cause of meningitis in this age group. A recent study determined that meningococcal disease occurs in around 2 or 3  per 100,000 infants each year.

Outside of the US, meningococcal disease is more common in certain geographic regions, particularly in a region in sub-Saharan Africa that includes Chad, Burkina Faso, Ethiopia, Niger, and other nations. This region is known as the “African meningitis belt”, where there are several meningococcal disease outbreaks a year. 

What vaccines prevent meningococcal disease?

There are 5 types (serotypes) of meningococcus. Vaccine age and dose requirements vary around the world, depending on the prevalence of each serotype in each region. In the US, there is a combination vaccine for four of these (MenACWY) and a separate vaccine for the fifth (MenB). Meningitis B and the MenB vaccine were the topic of our original post that we mentioned at the top of this article. This section will focus on the recommendations specific to the US.

Meningococcal Disease Vaccines: MenACWY

The MenACWY vaccine prevents infection from meningococcus A, C, W, and Y. This vaccine is built into the CDC’s recommended immunization schedule and is given in two doses: the first between ages 11 to 12, and the second at 16 years of age. This booster at 16 provides protection while teens are most vulnerable. Additionally, the CDC recommends that adults that are at high risk of infection also get vaccinated. 

Meningococcal Disease Vaccines: MenB

The MenB vaccine prevents infection from meningococcus B. In the US, the vaccine is recommended for children above the age of ten if they are at increased risk of getting meningococcal disease, as determined by their pediatrician. This would include children who are immunocompromised. For everyone else, the CDC suggests getting vaccinated between the ages of 16 to 18. However, this vaccine is not part of the regular vaccination schedule, and parents may have to request the vaccine from their doctor. 

Although the overall risk of getting meningococcal disease from meningococcus B is low for most individuals, its impact when these rare cases occur is very high. When the severity of harm is high, our risk tolerance should be lower. The fatality rate is high and, even if an individual survives, the chances that they will suffer lifetime damage is also high. In comparing risks, the vaccines are effective and the risk of vaccine side-effects is very low. Consequently, parents and teenagers should ask about the MenB vaccine, particularly if kids are headed to college dorms, or other group living situations, where meningococcal disease outbreaks most often occur. 

What vaccines prevent other causes of meningitis?

Hib vaccine

The Hib vaccine prevents infection from Haemophilus influenzae type b. This bacteria is the leading cause of meningitis in children under the age of five. The Hib vaccine is given in three or four doses, where the doses are given at two months, four months, and 12 to 15 months of age. If four doses are given, an additional dose is provided at six months. Whether three or four doses are given will depend on the brand of vaccine. This vaccine is part of the CDC recommended vaccine schedule.

Pneumococcal vaccine

The Pneumococcal vaccine (available as PCV13 or PPSV23) prevents infection from the bacteria Streptococcus pneumoniae. This bacteria causes pneumococcal disease, whose symptoms and complications include infection of tissues surrounding the lungs, heart, and brain. The latter leads to meningitis. The PCV13 vaccine is recommended for children under the age of two in a series of four doses. This vaccine is also part of the CDC recommended vaccine schedule.

MMR (Measles Mumps Rubella Vaccine)

When measles or mumps occur in children, meningitis is one of the potential complications that can arise. Although meningitis caused by measles is rare, one in seven cases of mumps lead to meningitis. Luckily, the MMR vaccine prevents both diseases and is safe and effective. This vaccine is given in two doses: the first dose occurs between 12-15 months and the second occurs between years four to six. This vaccine is also part of the CDC recommended vaccine schedule.

Vaccines save lives

Meningitis, particularly meningococcal disease, can be lethal or cause lifelong disability. Fortunately, we can prevent many bacterial and viral causes of meningitis by vaccinating our children according to the vaccine schedule and requesting the MenB vaccine.

Patti and Alicia are raising awareness about the meningococcal vaccines because their daughters had received only one (MenACWY) of the two types of vaccines. They were not aware that these two vaccines prevent disease caused by different serogroups of meningococcus. They thought that their children were protected. My heart breaks for them and for their loss, and I hope this article helps raise awareness in their honor and memory. You can learn more about them and their work at the Meningitis B Action Project.