Immunization and vaccination are the most important intertwin public health interventions and cost-effective strategies aimed at preventing or reducing both the morbidity and mortality associated with infectious diseases which affect mostly the quality of life of children, pregnant women and travelers. Immunization is the process by which the body is immune or have the ability to resist infectious diseases through administered vaccines which stimulate body’s own immune system for protection or fortification against subsequent infections, diseases or agent called immunogen. The goals of immunizations are to protect you and your neighbours from getting infectious vaccine preventable diseases and to enjoy sustained seamless quality health.
Vaccination is the administration of potent vaccine into the body to help improve the immune system to the point of developing protection against specific infectious diseases. It is an active form of immunization. Remember that vaccinations administered by expert health care professionals in standard health facilities are safer than infectious diseases. In simple terms, vaccination is the scheduled administration of vaccines parenterally, orally or by spraying into the body while immunization is the security the body enjoys by factor of the protection induced by the stimulated immune system upon the administration of relevant vaccines. Specific vaccines are produced against target infectious diseases.
For the purpose of this public document, do excuse the use of immunization and vaccination interchangeably. Generally, immunizations or vaccinations protect target populations from infectious diseases by introducing vaccines that trigger immune response which tricks the body to think that it had been exposed to a disease to fight naturally. Vaccines contain, in killed or highly weakened form, the same antigens or parts of the antigens that cause the diseases they are fighting. Immunity (the ability of the body to defend itself against diseases caused by certain bacteria or viruses) may occur naturally (after exposure to the bacteria or viruses). Expert health care professionals can provide immunity through vaccinations.
In general terms, the primary benefits of immunizations are to reduce mortality and morbidity; promote quality life, good health and survival amongst children and women especially. Immunization is a key factor in lowering incidences of diseases and frequent visits to the hospitals by children and adults, thereby maximizing the use of time and money. A deadly disease of public importance which causes paralysis and death among children is poliomyelitis, still found in developing parts of the world particularly among people who have never had the poliovirus vaccine, who missed doses of the vaccine or travelers to areas where poliomyelitis is still prevalent.
Types of immunization
There are two types of immunization. They are:
Active immunization: This involves administering an immunogen which can be live/attenuated, killed/inactivated, toxoid or subunit in origin. Active immunization occurs when a living body is exposed to an immunogen in a controlled way that the body can learn to protect itself from further or future infections. Artificially acquired active immunity can be stimulated by a vaccine containing antigen. Active immunization stimulates the body’s natural defense mechanisms which responds to a vaccine by producing substances such as antibodies and white blood cells. The antibodies and white blood cells recognize and attack the specific bacteria or virus inside the vaccine. So, any time someone is exposed to a specific bacteria or virus, the body efficiently and automatically produces antibodies and other substances to prevent or lessen the attack of infections or diseases. The effectiveness of vaccine depends on the immune system’s ability to replicate and elicit response that adequately mimic the natural infection.
Passive immunization: Here, pre-formed antibodies of the immune system are usually administered directly into individuals who are recently exposed to infections. Vaccine-provided antibodies or lymphocytes made from animals or human donors can confer passive immunity. Passive immunization with serum or globulin (antibodies) from immune persons has been administered to protect people from viral infections. This type of immunization is good for people whose immune system does not respond sufficiently to an infection, who acquire an infection before completing vaccination or people whose occupations easily expose them to infections. Passive immunization occurs physiologically and lasts for few weeks within which the body gets rid of the injected antibodies. It can be used to transfer antibodies from pregnant mothers to their children in order to protect the baby before and shortly after birth. Artificial passive immunization is passed through injection especially in cases of recent outbreak of a particular disease and for an emergency treatment of toxicity as in tetanus infection.
Types of vaccines for immunization
There are four major types of vaccines. They include:
- Live-attenuated vaccines: Are against Measles, Mumps, Rubella (MMR), Rotavirus, Yellow fever, Smallpox, Varicella and Influenza. It is very important to note that for safety concerns, vaccines containing live organisms or viruses should be avoided or delayed in AIDS patients, pregnancy or patients taking immunosuppressants.
- Inactivated vaccines: Contain live but weakened organisms or viruses. The examples are Bacilli Calmette Guerin (BCG) vaccine against Tuberculosis, Oral polio vaccine, Oral Cholera vaccine and Oral typhoid vaccine.
- Subunit, recombinant, polysaccharide or conjugate vaccines: These vaccines are produced through recombinant Deoxyribonucleic acid technology. They include vaccines against: Haemophilus influenzae type b (Hib) disease, Hepatitis B, Human papillomavirus, Whooping cough (part of the DTP combined vaccine), Pneumococcal disease, Meningococcal disease and Shingles.
- Toxoid vaccines: Are altered form of toxins produced from toxins, poisons or chemicals secreted by certain bacteria or virus that has been weakened or made harmless. The secretion from the harmless virus or bacteria elicits immune response against the harmful effects of the toxin, infection or disease caused by bacteria or virus that produce the toxins. The examples of toxoids are: Whooping cough (Pertussis), Diphtheria and Tetanus vaccines.
Routes of vaccine administration
Vaccines and antibodies are normally administered:
- By injection into muscle (intramuscularly)
- By injection under the skin (subcutaneously)
- By injection into the vein (intravenously)
- Into the nose by spraying
- Orally as drops
Importance of immunization
At about the end of the fourteenth century before the inauguration of the use of immunization, vaccination or inoculation to stimulate immunity, people were immune to some infectious diseases after surviving their attacks. It means that immunity through immunization is achieved without the consequence of ill-health and the risk of potential life-threatening complications from infectious diseases. Once a person is immunized, specific immune cells called memory cells protect the individual from re-infection when they are in contact with that same disease tomorrow. Some vaccines provide lifelong immunity while some require booster doses to maintain immunity.
Globally, more than two million deaths are delayed or prevented annually through vaccination which stimulate development of immunity against infectious diseases. Despite this fact, vaccine-preventable diseases remain the most common cause of childhood morbidity/mortality resulting to approximately three million deaths yearly on global scale.
Over the years, there are improvements in accelerated routine and supplementary immunization activities especially in developing nations. Immunizations are often more comfortable, less risky and safest way for adults and children to gain immunity against specific vaccine preventable deadly diseases. In developed nations especially, some infections or diseases are almost completely eradicated through the use of relevant immunizations, courtesy of dedicated health care professionals and elite parents who do not miss any routine vaccination schedule for targeted groups of children and adults.
Immunizations prevent families from getting infectious diseases for which there are no ready medical treatments. The infections or diseases can result to serious complications and even death. Immunization is the only enabling health factor by which the body defend itself better against diseases caused by certain bacteria or viruses. When people are fully immunized against a disease or infection, they are usually protected from the disease, or experience only a reduced form of attack of the disease or infection because no vaccine is 100% effective. Immunizations protect us from serious diseases or infections and also prevent the spread of the diseases to others. In communities and countries, immunizations have actively interrupted epidemics of major infectious diseases such as measles, mumps, whooping cough; and almost eradicated smallpox and poliomyelitis.
According to the American Centers for Disease Control and Prevention, active immunization or vaccination is so important that the Center named it one of the “Ten Great Public Health Achievements of the 20th Century”.
It is therefore evident that immunization is a veritable tool for controlling and eliminating life-threatening infectious diseases that have the potential of effecting more than three million deaths yearly. It is the most cost-effective health prevention and proven strategies that is easily accessible to most hard-to-reach, vulnerable populations and other defined target groups. Globally, immunizations have effectively prevented serious disease and promoted good health and quality life.
Paying close attention and observing strictly the immunization schedules and supplementary initiatives are very important for improving the health, and stopping spread of diseases in families and global community. Available vaccines today are very effective, well tolerated with minor side effects.
Few people with impaired immune systems (like diabetes, HIV or cancer patients) may be susceptible to diseases, because they may not benefit fully from vaccinations or may not develop immunity even after been vaccinated. Such individuals who can serve as ready host for certain infections, enjoy protection against the epidemics of infectious diseases when people in their environment who could spread diseases are fully vaccinated. Also, the target population living in healthy conditions but are not fully immunized are not better than the people whose immune systems are compromised in terms of import and spread of vaccine preventable diseases in schools and densely populated areas. Therefore, get vaccinated and stop the import and spread of vaccine preventable infections, locally and internationally. It simply means that if you are not timely and fully immunized with relevant vaccines, you are not protected and you are harmful to your neighbours, causing preventable huge and diverse costs to humanity.
It is a fact that vaccination provides the most enduring and effective protection against vaccine preventable diseases that can be serious, causing life-threatening complications that can lead to hospitalization. Immunization is important for both children and adults for maintenance of immunity and promotion of healthy aging.
Globally, immunizations can protect both children and adults from:
- Human papillomavirus (HPV)
- Measles (red measles)
- Rubella (German measles)
- Tetanus (lockjaw)
- Varicella (chickenpox)
- Pertussis (whooping cough)
- Pneumococcal infection
- Blood infection
- Ear infection
- Haemophilus influenzae type b
- Hepatitis A
- Hepatitis B
It is important to emphasize that appropriate immunizations with potent vaccines are easier and less risky formula to trigger the immune system to respond and build sustained immunity against the above severe infections that can cause major health challenges. Visit standard health facilities for expert advice and monitoring of your health and vaccination status; and for the delivery of reliable and recommended immunization services by health care professionals. It is absolutely necessary you take charge and be a partner in your good health protection and promotion through immunizations.
Certain vaccines are given only once while others require support or booster doses to maintain adequate immunity and sustained protection against vaccine preventable infections or diseases in children and adults. Generally, the schedule of recommended routine immunizations can differ based on location, child’s health status, types and availability of vaccines. Some vaccines are combined mainly for convenience. These routine immunization schedules whose delivery should be tracked or recorded with health programme cards include:
- At birth: Hepatitis B vaccine is normally administered within 24 hours of birth, at any age or at 1 month of birth particularly for low weight infants. The second dose should be given 1 to 2 months after the first dose.
- At two months: The first doses of the following vaccines are administered. They are: Diphtheria, Pertussis and Tetanus (DPT) vaccines, Haemophilus influenzae b (Hib)vaccine, Oral inactivated Poliovirus (OP) vaccine, Pneumococcal conjugate (PC) vaccine and Rotavirus vaccine.
- At four months: The second doses of the following vaccines are administered. They include: Diphtheria, Pertussis and Tetanus (DPT) vaccines, Haemophilus influenzae b (Hib) vaccine, Oral inactivated Poliovirus (OP) vaccine, Pneumococcal conjugate (PC) vaccine and Rotavirus vaccine.
- At six months: The third doses of the following vaccines may be administered. They are: Diphtheria, Pertussis and Tetanus (DPT) vaccines, Haemophilus influenzae b (Hib)vaccine, Pneumococcal conjugate (PC) vaccine and Rotavirus vaccine.
- At above six months and annually: Influenza (Flu) vaccine is recommended.
- At six to eighteen months: The doses of the following vaccines are administered. They are: Oral inactivated poliovirus (OP) vaccine and Hepatitis B vaccine.
- At twelve to fifteen months: Haemophilus influenzae b (Hib)vaccine, Pneumococcal conjugate (PC) vaccine, Chickenpox (Varicella) vaccine and combined Measles, Mumps and Rubella (German measles or MMR) vaccines are recommended.
- At twelve to twenty-three months: Hepatitis A vaccine is given at interval of at least 6 months.
- At fifteen to eighteen months: Combined Diphtheria, Pertussis and Tetanus (DPT) vaccine is recommended.
- At four to six years: Combined Diphtheria, Pertussis and Tetanus (DPT) vaccine, Oral inactivated Poliovirus vaccine (OPv), Chickenpox (Varicella) vaccine and combined Measles, Mumps and Rubella (German measles or MMR) vaccine are recommended.
- At eleven to twelve years: Human papillomavirus vaccine, combined Diphtheria, Pertussis and Tetanus (DPT) booster (also recommended during each pregnancy) and Meningococcal conjugate vaccines are given.
- At sixteen to eighteen years: Meningococcal B vaccine may be given.
- At special circumstances, particularly for travelers and during outbreaks: Hepatitis A vaccine, combined Measles, Mumps and Rubella (German measles or MMR) vaccine, Oral inactivated Poliovirus vaccine (OPv), Pneumococcal conjugate (PC) vaccine, Meningococcal B vaccine and Influenza (Flu)vaccine are recommended.
Though improved sanitation, hygiene and other living conditions have generally promoted healthier environment and reduced the risks that favour exposure to vaccine preventable diseases especially in disease endemic regions, all the recommended childhood immunizations and booster vaccines are still essential for sustainable quality life.
Efficacy of vaccines and possible side effects of immunization
Most of the recommended childhood and adult immunizations are 90%-100% effective against vaccine preventable infections, according to experts. However, for reasons that are not fully understood, occasionally a child will not have total immunity against a disease after receiving a vaccine. This is the more reason to get children fully vaccinated because some children in whom the vaccine is 100% effective, protect those few who have not been completely immunized, thereby reducing everyone’s chance of exposure to preventable infections.
The only reason for vaccination restriction is in case of a serious, life-threatening allergy like anaphylactic reaction or shock which could result to facial swelling, difficulty in breathing or dizziness. This restriction is critical only in poorly equipped health facilities where the above vaccine-induced reaction is difficult to be managed immediately.
With today’s best practices in vaccine production and modern equipment, the myths and misinformation about vaccine safety and immunizations are regarded as old fables against the quality life of humanity and derogatory marks of underdevelopment, illiteracy and ignorance. Truly, vaccines are drugs which may cause side effects, but the good thing is that the minor side effects are insignificant compared to the infectious diseases that proven vaccines prevent.
The side effects mostly experienced include redness, localized swelling in the site of the injection, soreness, low-grade fever or body hotness. Minor irritation and vomiting are rare. Usually the side effects are easily, readily and appropriately handled by health care professionals. Moreover, the side effects are not harmful and they usually disappear within few days.
For some adults who express nervousness or fear of injections, it is advised you take calming breaths or cough as the needle goes into your body in less than a second. However, in case of any unusual health problem after vaccination, doctors, pharmacists, nurses or a member of the general public should keep or issue reports on Vaccine Adverse Event (VAE) to the designated disease control centres for relevant documentation and interventions.
Immunizations or vaccinations which have major objectives of preventing the attacks and spread of infectious diseases, suffer recurrent setbacks especially in developing economies. Some of the factors militating against full immunizations coverages include:
- Ethnicity, misconception or misinformation and religious beliefs or myths.
- Inadequate vaccines and investment in personnel, facilities and support drugs plus poor management of existing resources.
- Lack of relevant technologies, basic health infrastructure and tools.
- Lack of sufficient political will in favour of implementing sustainable immunization policies, plans and strategies.
- Lack of adequate and sustained public education/awareness creation and community engagement through targeted advocacy on immunization programmes.
- Unreliable monitoring of the performance indicators through quality on-going epidemiological surveillance, reliable laboratory confirmation and impact assessments of the target population (children and women).
- Internal conflicts or wars, adverse weather conditions and hard-to-reach/border communities.
High immunizations coverages are good health output with the ultimate outcome of decimating or eradicating the incidences of morbidity and mortality from vaccine preventable infections. Also, high immunizations coverages are the measure of protection and break in the transmission or spread of infectious diseases locally or globally. Therefore, the way forward in achieving high and sustained immunizations coverages hinges on conscious and strategic efforts on the parts of all stakeholders in tackling the above challenges.