MeNZB was a

vaccine A vaccine is a biological Dosage form, preparation that provides active acquired immunity to a particular infectious disease, infectious or cancer, malignant disease. The safety and effectiveness of vaccines has been widely studied and verifie ...

against a specific strain of group B

meningococcus ''Neisseria meningitidis'', often referred to as meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a ...

, used to control an epidemic of meningococcal disease in

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. Most people are able to carry the meningococcus bacteria safely with no ill effects. However, meningococcal disease can cause

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or ...

and

sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...

, resulting in brain damage, failure of various organs, severe skin and soft-tissue damage, and death. Immunisation with MeNZB requires three doses, administered approximately six weeks apart (except in newborns, who have them in conjunction with their 6-week, 3-month and 5-month injections). People who have been fully immunised may still carry the meningococcus bacteria and may still contract meningococcal disease.

Components

Each dose is 0.5 ml and contains: *25 mcg of outer membrane vesicles from the ''

Neisseria meningitidis ''Neisseria meningitidis'', often referred to as meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a ...

'' group B strain NZ98/254. The vaccine does not contain any whole

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

(alive or dead). The "outer membrane vesicles" it contains are a small part of the "skin" of the bacteria that let the immune system recognise and prepare for being infected with the real thing. MeNZB vaccine does not contain any human,

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...

, or bovine (cow) products,

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

products,

neomycin Neomycin is an aminoglycoside antibiotic that displays bactericidal activity against gram-negative aerobic bacilli and some anaerobic bacilli where resistance has not yet arisen. It is generally not effective against gram-positive bacilli and an ...

or the preservative

thiomersal Thiomersal (INN), or thimerosal (USAN, JAN), is an organomercury compound. It is a well-established antiseptic and antifungal agent. The pharmaceutical corporation Eli Lilly and Company gave thiomersal the trade name Merthiolate. It has been u ...

(mercury). There are no live meningococcal bacteria in the vaccine and it is not possible to catch the disease or become a carrier of the disease from the vaccine. *1.65 mg of

aluminium hydroxide Aluminium hydroxide, Al(OH)3, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is amphoteric, i.e., it has both basic and ...

(an

adjuvant In pharmacology, an adjuvant is a drug or other substance, or a combination of substances, that is used to increase the efficacy or potency of certain drugs. Specifically, the term can refer to: * Adjuvant therapy in cancer management * Analgesic ...

). The immune system will normally not mount an immune response to the outer membrane vesicles if they are presented alone. The presence of the adjuvant forces the immune system to respond to the membrane vesicles by acting to prevent their breakdown and elimination, while causing local tissue damage to provoke the desired immune reaction. *

histidine Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the de ...

(to stabilise the pH). The histidine pH buffer is to ensure the vaccine stays as close as possible to the pH of human body fluids. This is to ensure the immune system does not waste time trying to neutralise the vaccine instead of responding to the outer membrane vesicles. *normal

saline Saline may refer to: * Saline (medicine), a liquid with salt content to match the human body * Saline water, non-medicinal salt water * Saline, a historical term (especially US) for a salt works or saltern Places * Saline, Calvados, a commune in ...

. The saline (sterile salt and water) is also like packaging. It is required so that all of the above can be dissolved into a solution that can be injected. It is the same salinity (saltiness) as normal human body fluid. The antigen in MeNZB is prepared from B:4:P1.7b,4 (NZ 98/254 ) ''N. meningitidis'' strain, grown in a fermentor. The bacteria are grown in a synthetic culture medium containing sugar, essential amino acids and essential elements such as iron and potassium. The fermentation does not use bovine or porcine products. The cellular outer membranes are extracted with the detergent deoxycholate, which kills the bacteria. Outer membrane vesicles are purified out of the culture medium by ultracentrifugation, stabilised by histidine and then adsorbed to aluminium hydroxide Al(OH)₃ as an adjuvant. Purification is achieved by ultrafiltration/diafiltration.

Impact

Since its introduction in 2004 the vaccine has had a dramatic impact on the meningitis epidemic began in 1991. Between 2004 and 2006 New Zealand offered free MeNZB vaccination to anyone under the age of 20. Routine immunisation for babies and preschoolers continued until June 2008. The last phase of this programme, immunisation for people with a high medical risk, ended in March 2011. Reasons given for this halt of the programme include that the epidemic was coming to an end, and that immune protection given by the vaccine is only short-term. The primary analysis estimated MeNZB to have an effectiveness of 77% after 3 doses and a mean follow-up time of 3.2 years. As ''

N. gonorrhoeae ''Neisseria gonorrhoeae'', also known as ''gonococcus'' (singular), or ''gonococci'' (plural), is a species of Gram-negative diplococci bacteria isolated by Albert Neisser in 1879. It causes the sexually transmitted genitourinary infection gon ...

'' and ''N. meningitidis'' are closely related bacteria and have 80–90% homology in their genetic sequences some cross-protection by meningococcal vaccines against ''N. gonorrhoeae'' infections is plausible. A study published in 2017 showed that MeNZB vaccine provided a partial protection against

Gonorrhea Gonorrhea, colloquially known as the clap, is a sexually transmitted infection (STI) caused by the bacterium '' Neisseria gonorrhoeae''. Infection may involve the genitals, mouth, or rectum. Infected men may experience pain or burning with ...

. The vaccine efficiency was calculated to be 31%.

References

External links

New Zealand Ministry of Health immunisation information.

Immunisation Advisory Centre, University of Auckland. Evidence based information on meningococcal disease and MeNZB vaccine.

* ttp://www.scoop.co.nz/stories/GE0505/S00181.htm New Zealand Ministry of Health response to article linked above
Press release: Minister Misleads Kim Hill and Public on MeNZB(tm)

* ttp://www.immune.org.nz/default.asp?a=653&t=589&View=FullStory&newsID=36 Response to press release linked above: Unethical anti-science scaremongering
Press release: MeNZB(tm) Vaccination Campaign Starts Derailing

News article: Officials praise meningococcal B vaccine coverage

TV news item covering vaccination campaign

* ttp://tvnz.co.nz/view/page/411319/592791/ News article: Adverts inform parents on vaccine
Press release: MeNZB Early Indications Graph
{{Vaccines Meningococcal vaccines Subunit vaccines