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Availability And Storage Of Vaccines In Community Pharmacies
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Conjugate Vaccines
Certain bacteria have polysaccharide outer coats
that are poorly immunogenic. By linking these outer coats to proteins
(e.g., toxins), the immune system can be led to recognize the
polysaccharide as if it were a protein antigen. This approach is used in
the Haemophilus influenzae type B vaccine
Experimental Vaccines
A number of innovative vaccines are also in development and in use, they include;
Dendritic cell vaccines
The
combine dendritic cells with antigens in order to present the antigens
to the body’s white blood cells, thus stimulating an immune reaction.
These vaccines have shown some positive preliminary results for treating
brain tumors (Kim and Liau, 2010) and are also tested in malignant
melanoma (Anguille, et al., 2014).
Recombinant Vector
By combining
the physiology of one micro-organism and the DNA of the other, immunity
can be created against diseases that have complex infection processes
DNA vaccination
An
alternative, experimental approach to vaccination called DNA
vaccination, created from an infectious agent’s DNA, is under
development. The proposed mechanism is the insertion (and expression,
enhanced by the use of electroporation, triggering immune system
recognition) of viral or bacterial DNA into human or animal cells. Some
cells of the immune system that recognize the proteins expressed will
mount an attack against these proteins and cells expressing them.
Because these cells live for a very long time, if the pathogen that
normally expresses these proteinsis encountered at a later time, they
will be attacked instantly by the immune system. One potential advantage
of DNA vaccines is that they are very easy to produce and store. As of
2015, DNA vaccination is still experimental and is not approved for
human use (Arce-Fonseca,et al., 2015)
T-cell receptor peptide vaccines
These
are under development for several diseases using models of valley
fever, stomatitis, and atopic dermatitis. These peptides have been shown
to modulate cytokine production and improve cell mediated immunity.
Targeting of identified bacterial proteins
Targeting
of identified bacterial proteins that are involved in complement
inhibition would neutralize the key bacterial virulence mechanism (Meri,
et al., 2008).
While most vaccines are created using inactivated or
attenuated compounds from micro-organisms, synthetic vaccines are
composed mainly or wholly of synthetic peptides, carbohydrates, or
antigens.
Valence
Vaccines may be monovalent (also called
univalent) or multivalent (also called polyvalent). A monovalent vaccine
is designed to immunize against a single antigen or single
microorganism (Scot, 2004)). A multivalent or polyvalent vaccine is
designed to immunize against two or more strains of the same
microorganism, or against two or more microorganisms (Sutter et al.,
1999). The valency of a multivalent vaccine may be denoted with a Greek
or Latin prefix (e.g., tetravalent or quadrivalent). In certain cases a
monovalent vaccine may be preferable for rapidly developing a strong
immune response (Neighmond, 2010).
Heterotypic
Also known as
Heterologous or “Jennerian†vaccines these are vaccines that are
pathogens of other animals that either do not cause disease or cause
mild disease in the organism being treated. The classic example is
Jenner’s use of cowpox to protect against smallpox. A current example is
the use of BCG vaccine made from Mycobacterium bovis to protect against
human tuberculosis (Scot, 2004).
1.2 Challenges to Vaccine Utilization in Nigeria
Recent
WHO estimates indicate that close to amillion children (868,000
children) under the age office years die in Nigeria each year and this
placesNigeria in the second position in terms of globalannual childhood
deaths after India (Ayene, 2014). The continued low uptake of
immunization threatens Nigeria’s efforts at meeting the Millennium
Development Goal (MDG) 4, which aims to significantly reduce child
mortality. Vaccine preventable deaths comprise about twenty percent of
childhood deaths (FBA Systems Analyst, 2005). There is no doubt that the
major challenges to effective vaccine utilization or routine
immunization in Nigeria ranges from religion, political, lack of storage
facilities amongst others as discussed below.
Politics
Politics
is most often related to the art and the activities employed to
governing a country or society but it can also within good reason be
extended to the practice and theory of influencing other people on a
civic or individual level (Abdulraheem, et al., 2011). Governance
includes the processes of determining policies to address different
problems, including health challenges that arise within a state. In the
context of routine immunization, politics is relevant to the development
of the health system. Questions regarding what policies to adopt with
regard to health issues such as routine immunization have political
undertone (Anyene, 2014). Policies regarding the primary health care
system within which routine immunization is undertaken in Nigeria is
linked to politics. Political issues such as leadership of Local
Government Areas (LGA), allocation to the LGAs et cetera, eventually
affects primary health care, as that level of government is mostly
responsible for it. It is also important to note in Nigeria that the
politics of routine immunization is broadly spread from the top,
starting with the Federal Executive Council, the Legislature (NASS),
Minister of Health and the Federal Ministry of Health, the Governors,
the Commissioners and the State Ministries of Health, to the Local
Government Chairmen and all 774 local governments in Nigeria.
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