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    Neisseria meningitidis (meningococcus)

    Also known as meningococcus, N. meningitidis, meningococcal bacteria

    Neisseria meningitidis, or meningococcus, is a bacterium that about 1 in 10 people carry harmlessly in the throat. Occasionally it invades and causes meningitis or bloodstream infection.[1][2] Even with antibiotics, 10 to 15 in 100 patients die.[3] US cases reached 463 in 2025, driven by serogroup Y, and MenB caused unusual outbreaks in England in 2026.[4][5]

    Editor reviewedStrict sourcingUpdated WikiHealth and medicine, Life sciences
    Key facts

    Neisseria meningitidis, known as meningococcus, is the bacterium behind meningococcal disease, a name for any infection it causes. The two most common forms are meningitis and bloodstream infection.[2] It is in the news in 2026 because US cases are above pre-pandemic levels and England had unusual MenB outbreaks among young people.[4][6] This page is not medical advice; talk to a clinician about symptoms or vaccination.

    Carriage and spread

    About 1 in 10 people carry N. meningitidis in the back of the nose and throat without being ill.[1] It spreads through saliva and respiratory secretions. It generally needs close or lengthy contact and is less contagious than cold or flu viruses.[7] UKHSA says carriage is more common among teenagers and students, who mix closely with many new people.[8] Close contacts of a case receive preventive antibiotics.[9]

    Disease and outcomes

    Meningococcal disease can begin like flu and worsen rapidly.[10] When the bacteria cause sepsis, a rash that does not fade under a pressed glass may appear, though not always.[11] Even with antibiotics, 10 to 15 in 100 people with meningococcal disease die, and one in five survivors has long-term disabilities.[3]

    Serogroups

    Meningococci are divided into serogroups, including MenA, MenB, MenC, MenW, MenX and MenY. Serogroups B, C, W and Y cause most US cases.[12] Vaccines target specific serogroups, so the strain matters. MenACWY vaccine does not protect against MenB.[13] In the African meningitis belt, serogroup A caused 80-85% of epidemics before a conjugate vaccine was rolled out from 2010. Mass campaigns cut confirmed serogroup A disease by 99% in vaccinated populations.[14]

    US cases have risen sharply since 2021. The CDC counted 463 confirmed and probable cases in 2025 (preliminary data), the second-highest total since 2013, with serogroup Y driving much of the increase.[4] Since 2019 the CDC has also detected serogroup Y isolates resistant to penicillin and ciprofloxacin.[15] Rates are highest in babies under 1 and in 16- to 23-year-olds.[16]

    England diagnoses about 300 to 400 cases a year.[17] In March 2026 a MenB outbreak in Kent caused fifteen cases within 48 hours, far faster than the usual 2 to 4 cases, and two people died.[6][5] Details are in the meningitis outbreaks tracker. Vaccines are compared in the meningitis vaccines guide.

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    Questions readers ask

    How does meningococcus spread?

    Through saliva and respiratory secretions. It generally needs close or lengthy contact and is less contagious than cold or flu viruses.[7]

    Who is most at risk?

    In the US, rates are highest in babies under 1, with a second peak in adolescence; 16- to 23-year-olds have the highest rates among adolescents and young adults.[16]

    Why are US cases rising?

    The CDC says cases have increased sharply since 2021 and now exceed pre-pandemic levels, with serogroup Y driving much of the rise.[4]

    Is meningococcus becoming resistant to antibiotics?

    Since 2019 the CDC has detected penicillin- and ciprofloxacin-resistant serogroup Y isolates in the US.[15]

    Does the MenACWY vaccine protect against MenB?

    No. MenACWY covers serogroups A, C, W and Y; MenB needs a separate vaccine or a pentavalent MenABCWY vaccine.[13][18]

    Sources

    · 18 claims from 5 publishers

    Each numbered claim is a statement we checked against the sources listed with it. Tap a number in the text to see its sources in place.

    1. [1]

      About 1 in 10 people carry N. meningitidis in the back of the nose and throat without being sick. confirmedas of 2026-10-11

    2. [2]

      Meningococcal disease is any infection caused by Neisseria meningitidis; its two most common forms are meningitis and bloodstream infection. confirmedas of 2026-10-11

    3. [3]

      Even with antibiotic treatment, 10 to 15 in 100 people with meningococcal disease die, and one in five survivors has long-term disabilities. confirmedas of 2026-10-11

    4. [4]

      The US reported 463 confirmed and probable meningococcal cases in 2025 (preliminary), the second-highest count since 2013; cases have risen sharply since 2021, driven largely by serogroup Y, and generally peak each year in January to March. confirmedas of 2026-09-29

    5. [5]

      A meningococcal disease outbreak in Kent, England, in March 2026 was linked to a MenB strain, and two people died. confirmedas of 2026-03-18

    6. [6]

      UKHSA called the Kent outbreak unusually fast, with fifteen cases emerging within 48 hours, whereas most outbreaks it manages involve 2 to 4 cases over a longer period. confirmedas of 2026-03-18

    7. [7]

      Meningococcal bacteria spread through saliva and respiratory secretions, generally require close or lengthy contact, and are less contagious than cold or flu viruses. confirmedas of 2026-10-11

    8. [8]

      UKHSA says carrying meningococcal bacteria is more common among young people, particularly teenagers and university students, because they spend a lot of time in close contact with new people. confirmedas of 2026-03-18

    9. [9]

      Close contacts of someone with meningococcal disease are given preventive antibiotics to clear the bacteria and reduce spread. confirmedas of 2026-10-11

    10. [10]

      Meningococcal disease can first look like a flu-like illness and then worsen rapidly. confirmedas of 2026-10-11

    11. [11]

      Meningococcal sepsis can cause a rash that does not fade when a glass is pressed against it, which can be harder to see on brown or black skin; not everyone gets a rash. confirmedas of 2026-10-11

    12. [12]

      There are several meningococcal strains, including MenA, MenB, MenC, MenW, MenX and MenY, and serogroups B, C, W and Y cause most US cases. confirmedas of 2026-10-11

    13. [13]

      MenACWY vaccine, given in UK schools in year 9 or 10, does not protect against MenB disease. confirmedas of 2026-06-12

    14. [14]

      Before a meningococcal A conjugate vaccine was deployed from 2010, serogroup A caused 80-85% of epidemics in the meningitis belt; mass campaigns cut confirmed serogroup A disease by 99% in vaccinated populations. confirmedas of 2026-10-11

    15. [15]

      Since 2019 the CDC has detected penicillin- and ciprofloxacin-resistant serogroup Y meningococcal isolates in the United States. confirmedas of 2026-09-29

    16. [16]

      Meningococcal disease rates are highest in babies under 1, with a second peak in adolescence; among adolescents and young adults, 16- to 23-year-olds have the highest rates. confirmedas of 2026-09-29

    17. [17]

      Around 300 to 400 cases of meningococcal disease are diagnosed in England every year. confirmedas of 2026-03-18

    18. [18]

      The US uses three types of meningococcal vaccine, MenACWY, MenB and pentavalent MenABCWY, each protecting against different serogroups. confirmedas of 2026-10-11

    Revision history (1)
    1. Page created.

    Created Oct 11, 2026. Last reviewed by an editor on Oct 11, 2026. Next scheduled review: Jan 11, 2027.

    Cite this page

    "Neisseria meningitidis (meningococcus)." ContentLora, updated Oct 11, 2026. https://contentlora.com/wiki/neisseria-meningitidis

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