MeningitisPatient friendly summary

  • In summer, UVB light appears to reduce the risk of meningococcal disease and meningitis by producing vitamin D.
  • Vitamin D may lower the risk of meningococcal disease and meningitis by strengthening the body’s immune system.

Meningococcal disease (MD) is caused by a bacterial infection. It carries a high mortality rate if left untreated. The bacteria is best known as causing meningitis.

However, it may also cause sepsis, a widespread blood infection. Sepsis is more damaging and dangerous.

Meningococcal disease is a major cause of illness, death, and disability worldwide.     

Risk factors

The most important risk factors are:

  • Contact with someone who has meningococcal disease
  • Low vitamin D blood levels            

Sunlight exposure and meningococcal disease risk

The rates of meningococcal disease infection coincide with the seasons:

  • Studies in many countries found that meningococcal disease/meningitis rates peak in the winter. They often overlap with influenza, which also peaks in the winter. There is less ultraviolet-B (UVB) light in the winter. There is also strong evidence that UVB levels influence the rate of influenza through production of vitamin D.
  • In New Zealand, the peak infection rate is in the rainy season. This is also in the winter.
  • Mali, a West African country, is in the northern tropics. Outbreaks of meningococcal meningitis peak between February and late May of each year. There is less UVB light at this time.
  • Data from the U.S. Centers for Disease Control and Prevention found that meningococcal meningitis peaks in January.
  • African-Americans have a higher rate of meningoccal deaths than white Americans. Darker skin absorbs UVB readily before it reaches the lower layer where vitamin D is producted. Therefore, people with darker skin produce less vitamin D.
  • A study in Philadelphia compared the effects of various pollution indices and UVB light on meningococcal disease rates. UVB light was the only factor that had a significant effect.

Vitamin D and meningococcal disease

Vitamin D levels

There are no reported papers comparing vitamin D levels and the effects on meningococcal disease. However, it seems very likely that solar UVB reduces the risk of meningococcal disease by producing vitamin D.

How vitamin D works

Most likely, vitamin D reduces the risk of meningococcal disease by strengthening the immune system. Vitamin D’s active form, calcitriol, stimulates production of cathelicidin and defensins. These proteins have antibacterial and antiviral effects. They may also neutralize bacterial toxins.


There are no reported studies using vitamin D to prevent meningococcal infections or meningococcal disease.

However, the disease peaks in the winter. This strongly suggests that keeping vitamin D levels above 40 ng/mL (100 nmol/L), especially in the winter, may reduce the risk of both diseases.


Vitamin D may be useful in treating meningococcal infections at the early stages. People who get the disease are likely to have low vitamin D levels at the time of infection. They might benefit most from taking high doses of vitamin D, up to 50,000 international units (IU) (1250 mcg)/day for several days. Then lower doses of vitamin D, 5000 IU (125 mcg)/day, might be taken for the duration of the illness. Within a day or two, vitamin D converts to calcitriol.

Find out more...

We will be adding a detailed evidence summary on this topic in the near future.  Please check back soon to find out more.

Page last edited: 17 May 2011