MenAfriVac is 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 ...
developed for use in
sub-Saharan Africa
Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...
for children and adults between 9 months and 29 years of age against meningococcal
bacterium
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 ...
''
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 A. The vaccine costs less than US$0.50 per dose.
History
Epidemics of meningococcal A meningitis, which is a bacterial infection of the thin lining surrounding the brain and spinal cord, have swept across 26 countries in sub-Saharan Africa for a century, killing and disabling young people every year. The disease is highly feared on the continent; it can kill or cause severe brain damage in a child within hours. Epidemics usually start at the beginning of the calendar year when dry sands from the
Sahara Desert
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, photo_caption = The Sahara taken by Apollo 17 astronauts, 1972
, map =
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begin blowing southward.
The largest
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 ...
epidemic
An epidemic (from Ancient Greek, Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of patients among a given population within an area in a short period of time.
Epidemics ...
in African history swept across sub-Saharan Africa from 1996 to 1997, numbering 250,000 new cases and taking 25,000 lives. Three years later, the
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
(WHO) held a technical consultation in Cairo, Egypt with African ministers of health and global health leaders to discuss meningitis and the development of a new vaccine.
At that meeting, representatives from eight African countries issued a statement saying that the development of a meningococcal vaccine to prevent epidemics was a high priority for them, and concluded that a
conjugate meningococcal vaccine would have the potential to prevent future epidemics. They estimated that the new vaccine could become available in three to seven years for US$0.40 to $1 a dose, providing protection for at least ten years.
A year later, in 2001, the
Bill & Melinda Gates Foundation
The Bill & Melinda Gates Foundation (BMGF), a merging of the William H. Gates Foundation and the Gates Learning Foundation, is an American private foundation founded by Bill Gates and Melinda French Gates. Based in Seattle, Washington, it was l ...
provided a ten-year, $70 million grant to establish the
Meningitis Vaccine Project, a partnership between PATH and WHO. The foundation charged the new project with development, testing, licensure and mass introduction of a meningococcal conjugate vaccine.
In 2002, the collaboration supported reinforced meningitis surveillance activities in 12 countries in Africa:
Benin
Benin ( , ; french: Bénin , ff, Benen), officially the Republic of Benin (french: République du Bénin), and formerly Dahomey, is a country in West Africa. It is bordered by Togo to the west, Nigeria to the east, Burkina Faso to the north ...
,
Burkina Faso
Burkina Faso (, ; , ff, 𞤄𞤵𞤪𞤳𞤭𞤲𞤢 𞤊𞤢𞤧𞤮, italic=no) is a landlocked country in West Africa with an area of , bordered by Mali to the northwest, Niger to the northeast, Benin to the southeast, Togo and Ghana to the ...
,
Cameroon
Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...
,
Central African Republic
The Central African Republic (CAR; ; , RCA; , or , ) is a landlocked country in Central Africa. It is bordered by Chad to the north, Sudan to the northeast, South Sudan to the southeast, the DR Congo to the south, the Republic of th ...
,
Chad
Chad (; ar, تشاد , ; french: Tchad, ), officially the Republic of Chad, '; ) is a landlocked country at the crossroads of North and Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic ...
,
Côte d'Ivoire
Ivory Coast, also known as Côte d'Ivoire, officially the Republic of Côte d'Ivoire, is a country on the southern coast of West Africa. Its capital is Yamoussoukro, in the centre of the country, while its largest city and economic centre is ...
,
Ethiopia
Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...
,
Ghana
Ghana (; tw, Gaana, ee, Gana), officially the Republic of Ghana, is a country in West Africa. It abuts the Gulf of Guinea and the Atlantic Ocean to the south, sharing borders with Ivory Coast in the west, Burkina Faso in the north, and To ...
,
Mali
Mali (; ), officially the Republic of Mali,, , ff, 𞤈𞤫𞤲𞥆𞤣𞤢𞥄𞤲𞤣𞤭 𞤃𞤢𞥄𞤤𞤭, Renndaandi Maali, italics=no, ar, جمهورية مالي, Jumhūriyyāt Mālī is a landlocked country in West Africa. Mali ...
,
Niger
)
, official_languages =
, languages_type = National languages[Nigeria
Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...](_blank)
and
Togo
Togo (), officially the Togolese Republic (french: République togolaise), is a country in West Africa. It is bordered by Ghana to the west, Benin to the east and Burkina Faso to the north. It extends south to the Gulf of Guinea, where its c ...
. The surveillance indicated an increased risk of outbreaks in the future and the continued need for a vaccine. MenAfriVac became available for widespread use in
African meningitis belt
The African meningitis belt is a region in sub-Saharan Africa where the rate of incidence of meningitis is very high. It extends from Senegal to Ethiopia, and the primary cause of meningitis in the belt is ''Neisseria meningitidis''.
The belt wa ...
countries in 2010.
Distribution in Mali and Niger was assisted by
Médecins Sans Frontières
(MSF; pronounced ), also known as Doctors Without Borders, is a humanitarian medical non-governmental organisation (NGO) or charity of French origin known for its projects in conflict zones and in countries affected by endemic diseases. M ...
.
Effectiveness evaluation
A 2013 article published in ''
The Lancet
''The Lancet'' is a weekly peer-reviewed general medical journal and one of the oldest of its kind. It is also the world's highest-impact academic journal. It was founded in England in 1823.
The journal publishes original research articles, ...
'' reported that the MenAfriVac vaccination campaign in Chad reduced meningitis incidence by 94%. In three regions of Chad, approximately 1.8 million people from 1 to 29 years old received a single dose of the vaccine in December 2011.
Vaccinating 70% of the population in that age group is enough to create "
herd immunity
Herd immunity (also called herd effect, community immunity, population immunity, or mass immunity) is a form of indirect protection that applies only to contagious diseases. It occurs when a sufficient percentage of a population has become imm ...
".
During the 2012 meningitis season no cases of the meningococcus sub-type serogroup A caused disease in places where mass vaccination took place. Carriers of serogroup A were found to decrease by more than 97% post-vaccination. Surveillance is needed to continue for several more years to establish the length of effective period of the vaccine and whether other meningococci serogroups may surge to replace serogroup A.
In November 2015, a special collection of 29 articles was published in the journal ''
Clinical Infectious Diseases
''Clinical Infectious Diseases'' is a peer-reviewed medical journal published by Oxford University Press covering research on the pathogenesis, clinical investigation, medical microbiology, diagnosis, immune mechanisms, and treatment of diseases ...
''—with guest editors from
Public Health England
Public Health England (PHE) was an executive agency of the Department of Health and Social Care in England which began operating on 1 April 2013 to protect and improve health and wellbeing and reduce health inequalities. Its formation came as a ...
and the former Meningitis Vaccine Project about the steps taken for the development, introduction, and evaluation of MenAfriVac. Immunization with MenAfriVac has led to the control and near elimination of deadly meningitis A disease in the African "meningitis belt". In 2013, only four laboratory-confirmed cases of meningitis A were reported by the 26 countries in the meningitis belt. But scientists warned that unless countries within the belt incorporate the meningitis A vaccine in routine immunization schedules for infants, there is a risk that the disease could rebound in 15 years' time. One of the journal studies found that a childhood vaccination strategy will be much cheaper than reacting to future epidemics with disruptive and costly case management and mass vaccination campaigns.
Eradication
In 2015, the caseload of the illness fell to zero in 16 countries that used MenAfriVac in mass vaccination campaigns. Ten other countries have not launched vaccination programs. Epidemics were expected to return in about 15 years unless MenAfriVac becomes a routine childhood vaccination as WHO recommended.
The tetanus toxoid protein used in the vaccine increased the share of people with long-term
tetanus
Tetanus, also known as lockjaw, is a bacterial infection caused by ''Clostridium tetani'', and is characterized by muscle spasms. In the most common type, the spasms begin in the jaw and then progress to the rest of the body. Each spasm usually ...
immunity from 20% to 59%, although it is not strong enough to stand alone against tetanus.
Neonatal tetanus
Neonatal tetanus (''trismus nascentium'') is a form of generalised tetanus that occurs in newborns. Infants who have not acquired passive immunity from an immunized mother are at risk. It usually occurs through infection of the unhealed umbilical ...
kills nearly 50,000 newborns a year in sub-Saharan Africa. Rates of neonatal tetanus fell by 25% in countries following a MenAfriVac campaign.
Manufacture
The Meningitis Vaccine Project partnered with
SynCo Bio Partners, a Dutch biotech company, and the US government's
Center for Biologics Evaluation and Research
The Center for Biologics Evaluation and Research (CBER) is one of six main centers for the Food and Drug Administration, U.S. Food and Drug Administration (FDA), which is a part of the U.S. Department of Health and Human Services. The current Dir ...
to develop MenAfriVac, and the
Serum Institute of India
Serum Institute of India (SII) is an Indian biotechnology and biopharmaceuticals company, based in Pune. It is the world's largest manufacturer of vaccines. It was founded by Cyrus Poonawalla in 1966 and is a part of Cyrus Poonawalla Group.
O ...
to manufacture it.
MenAfriVac is a
freeze-dried
Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process that involves freezing the product and lowering pressure, removing the ice by sublimation. This is in contrast to dehydration by most conve ...
vaccine of a
polysaccharide
Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wa ...
from a type of ''Neisseria meningitidis'' called group A. The polysaccharide has been purified by
affinity chromatography
Affinity chromatography is a method of separating a biomolecule from a mixture, based on a highly specific macromolecular binding interaction between the biomolecule and another substance. The specific type of binding interaction depends on the ...
and bound to a
carrier protein
A membrane transport protein (or simply transporter) is a membrane protein involved in the movement of ions, small molecules, and macromolecules, such as another protein, across a biological membrane. Transport proteins are integral transmembrane ...
called
tetanus toxoid
Tetanus vaccine, also known as tetanus toxoid (TT), is a toxoid vaccine used to prevent tetanus. During childhood, five doses are recommended, with a sixth given during adolescence.
After three doses, almost everyone is initially immune, but a ...
(TT). The TT is prepared by extraction by
ammonium sulfate precipitation Ammonium sulfate precipitation is one of the most commonly used methods for large and laboratory scale protein purification and fractionation that can be used to separate proteins by altering their solubility in the presence of a high salt concentra ...
and the toxin is inactivated with
formalin
Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section Fo ...
from cultures of ''
Clostridium tetani
''Clostridium tetani'' is a common soil bacterium and the causative agent of tetanus. Vegetative cells of ''Clostridium tetani'' are usually rod-shaped and up to 2.5 μm long, but they become enlarged and tennis racket- or drumstick-shaped when ...
'' grown in a modified
Mueller–Hinton agar
Mueller–Hinton agar is a microbiological growth medium that is commonly used for antibiotic susceptibility testing, specifically disk diffusion tests. It is also used to isolate and maintain ''Neisseria'' and ''Moraxella'' species.
It typi ...
.
References
External links
{{PATH (global health organization)
Meningitis
Meningococcal vaccines
Conjugate vaccines