Meningitis is a serious infection that causes inflammation of the membranes surrounding the brain and spinal cord. It can be caused by bacteria or viruses and leads to symptoms like headache, fever, and stiff neck. If left untreated, meningitis can result in permanent brain damage or even death.
What causes meningitis?
The most common causes of meningitis are:
- Viral infections like mumps, measles, and herpes
- Bacterial infections like Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae type B, and Listeria monocytogenes
- Fungal infections like Cryptococcus and Coccidioides
- Parasitic infections like toxoplasmosis
- Non-infectious causes like cancers and drug reactions
Viral meningitis is usually mild and clears up on its own. But bacterial meningitis is very serious and can be fatal if not treated immediately with antibiotics. Common bacteria that cause meningitis include Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type B (Hib).
Who is at risk of meningitis?
While anyone can get meningitis, certain groups are at higher risk:
- Infants less than 1 year old
- Children between 1-5 years old
- Teenagers and young adults 16-23 years old
- Older adults over 55 years old
- Those with weakened immune systems
- College students living in dorms
- Healthcare workers
- Those exposed during outbreaks
Infants and toddlers are at high risk as their immune systems are still developing. Teens and young adults have social behaviors like living in close quarters, smoking, and drinking alcohol that increase risk. Older adults have a weaker immune response. People with certain medical conditions like HIV/AIDS, diabetes, and those without a working spleen are also vulnerable.
How do you prevent meningitis?
The best way to prevent meningitis is through vaccination. There are vaccines available to protect against the common bacterial causes of meningitis:
- Hib vaccine – Protects against Haemophilus influenzae type B meningitis. Recommended for all children as a routine childhood immunization.
- Pneumococcal conjugate vaccine (PCV13) – Protects against 13 types of pneumococcal bacteria that can cause meningitis and other pneumococcal infections. Recommended for all children under 2 years and adults over 65 years.
- Meningococcal conjugate vaccine (MCV4) – Protects against 4 serogroups (A, C, W, Y) of Neisseria meningitidis. Recommended for all children at 11-12 years and a booster at 16 years. Also recommended for teens and young adults 16-23 years old.
- Meningococcal B vaccine (MenB) – Protects against serogroup B meningococcal disease. May be recommended for teens and young adults 16-23 years old.
Maintaining up-to-date vaccinations is crucial to prevent bacterial meningitis in infants, children, teens, and young adults. Older adults should also get recommended pneumococcal and meningococcal vaccines.
Who needs meningitis vaccines in the US?
The CDC recommends the following meningitis vaccination schedule in the US:
Infants and Children
- Hib vaccine at 2, 4, 6, and 12-15 months old
- PCV13 vaccine at 2, 4, 6, and 12-15 months old
- MCV4 first dose at 11-12 years old
Adolescents
- MCV4 booster at age 16 years
- MenB may be recommended at ages 16-18 years
Young Adults
- Those living in dorms or military barracks: MCV4 if unvaccinated
- Other 16-23 year olds may get MenB vaccine
Older Adults
- PCV13 and MCV4 if never vaccinated
In addition, anyone with high-risk medical conditions, without a working spleen, HIV, traveling to endemic areas, or exposed during an outbreak should get vaccinated. Overall, it’s important to stay updated per the CDC guidelines for your age group.
How effective are meningitis vaccines?
Meningitis vaccines are 85-100% effective at preventing meningitis caused by the bacteria they target:
| Vaccine | Targeted Bacteria | Effectiveness |
|---|---|---|
| Hib vaccine | Haemophilus influenzae type b | 95-100% effective |
| PCV13 vaccine | 13 types of Streptococcus pneumoniae | 85-90% effective |
| MCV4 vaccine | Serogroups A, C, W, Y Neisseria meningitidis | 85-100% effective |
| MenB vaccine | Serogroup B Neisseria meningitidis | 85-90% effective |
Getting vaccinated with the recommended meningitis vaccines is the most effective way to prevent bacterial meningitis caused by these pathogens. The protection lasts about 5-10 years depending on the vaccine.
How many doses of meningitis vaccine are needed?
The number of meningitis vaccine doses needed depends on a few factors:
- Age at first dose – More doses are needed if the first dose is at a younger age. For example, infants need 4 doses of Hib and PCV13 vaccine, while older children and teens need only 1-2 doses.
- Type of vaccine – Some vaccines require multiple doses to be effective, like Hib and PCV13. Others require only a single dose, like MenB.
- Time since previous dose – Booster doses may be recommended if a long time has elapsed since the previous dose to ensure protection.
- High-risk conditions – Additional doses may be needed for those at highest risk like asplenia patients and HIV individuals.
Below is a summary of the routine meningitis vaccine dosing schedule:
| Vaccine | Infants | Children | Adolescents | Young Adults | Older Adults |
|---|---|---|---|---|---|
| Hib | 3-4 doses (2, 4, 6, 12-15 mos) |
1 dose after 12 mos if unvaccinated |
– | – | – |
| PCV13 | 3-4 doses (2, 4, 6, 12-15 mos) |
1 dose after 24 mos if unvaccinated |
– | – | 1 dose |
| MCV4 | – | – | 2 doses (11-12 yrs, 16 yrs) |
1-2 doses if unvaccinated |
2 doses if unvaccinated |
| MenB | – | – | 2 doses | 2-3 doses | – |
In summary, infants and young children receive multiple doses of Hib and PCV13 vaccines as part of routine childhood immunizations. Older children, adolescents, and adults may need catch-up vaccinations if previously unvaccinated. Certain high risk groups may need additional doses.
Should you get a meningitis booster shot?
Meningitis booster shots may be recommended in certain situations:
- Before age 16 – A 2nd dose of MCV4 is recommended at age 16 years to boost protection in teens.
- Before college – An MCV4 booster is recommended if the last dose was before age 16. First-year dorm residents need at least 1 MCV4 dose.
- After MCV4 at ages 11-15 – A booster after 5 years is recommended up till age 21 years.
- Asplenia patients – Revaccination every 5 years with MCV4 and MenB may be advised.
- HIV individuals – MCV4 and MenB boosters every 5 years may be recommended.
- After Hib or PCV13 – Boosters are generally not needed except in high-risk cases.
Routine boosters for MCV4 meningococcal vaccine may be recommended for adolescents and high-risk groups. Hib and PCV13 boosters are uncommon. Consult your doctor to determine if you need a meningitis booster shot based on your vaccination history, age, and medical conditions.
How long does meningitis vaccine last?
The duration of protection provided by meningitis vaccines is:
- Hib vaccine – 5 years (booster not routinely needed)
- PCV13 – 5 years (booster not routinely needed)
- MCV4 – 5 years
- MenB – 1-3 years
Hib and PCV13 offer decent long-lasting protection. MCV4 and MenB immunity tends to wane quicker. MCV4 requires a booster dose after 5 years, especially in teens and high-risk groups. MenB may require re-vaccination every 1-3 years for sustained protection.
Can you get meningitis after vaccination?
Yes, it is possible to get meningitis even after vaccination but the risk is significantly lower. Reasons include:
- Getting an uncommon Streptococcus pneumoniae strain not in PCV13 vaccine
- Getting infected before full immunity from vaccine developed
- Exposure shortly before booster dose was due
- Waning immunity in high-risk groups
- Failure to complete multi-dose series
- Vaccine failure in small percentage
Vaccines reduce but don’t eliminate risk entirely. Continuing recommended dosing schedules and boosters, especially in high-risk settings like college dorms, helps sustain immunity. Prompt antibiotic treatment is still needed for suspected meningitis even after vaccination.
What are the side effects of meningitis vaccine?
Meningitis vaccines are generally safe but may cause mild side effects like:
- Soreness, redness, swelling at injection site
- Mild fever
- Fussiness, drowsiness in babies
- Headache, muscle aches
- Fatigue
- Loss of appetite
Rare side effects can include seizures, non-stop crying for 3+ hours in babies, and severe allergic reaction (anaphylaxis). These happen very infrequently.
The benefits of protection against meningitis outweigh the small risk of side effects. Except for severe allergic reaction, side effects are generally mild and resolve in a few days. Speak to your doctor about any concerns with vaccines.
Conclusion
Meningitis is a concerning infection that can lead to lasting neurological problems and even death. Getting vaccinated is the best defense against bacterial meningitis.
Infants, children, teens, and select adults should follow CDC guidelines for routinely recommended meningitis vaccines like Hib, PCV13, MCV4, and MenB. The number of doses needed depends on the vaccine and age group.
Booster doses of some vaccines may be advised after 5 years or before college. But in general, 2-4 vaccine doses in childhood provides decent long-term protection.
Vaccination significantly reduces but doesn’t eliminate meningitis risk entirely. But the protection against this potentially devastating illness makes keeping up-to-date with immunizations very important.
