Vaccines and immunization are essential elements of any primary health care program and the best health investment. World Health Organization (WHO) collaborates with countries globally to create awareness of the importance of immunization. WHO also ensures that the governments acquire all the necessary technical support and guidance to fulfill quality-assured immunization goals.

Immunization is a process by which a person or a community becomes protected against a disease through vaccination. The government launched many immunization programs so that a larger group of the population, children, and pregnant females, become protected from several morbidities. Both children and adults must get vaccinated according to their vaccination schedule to protect themselves from many diseases.

Safe and effective vaccines are a revolutionary tool in prevention and treatment medicine. Effective vaccines and immunization protect us from many infectious diseases. Vaccines are available for every age group, from infancy to older people.

Vaccines are one of the milestone developments in the medical world. They have decreased the child mortality rate by several percent and have saved millions of lives. Vaccines help to keep us and our society safe. Let’s first discuss what a vaccine is.

What is the vaccine?

The vaccine is a biological concoction that induces immunity in our body to a particular disease-causing infection. It contains weakened or killed forms of microbes, surface protein, or toxins. These agents trigger our body’s immune system and produce active acquired immunity against future infection of a particular disease. Vaccines can be:

Prophylactic vaccines: These mitigate the effect of the future infectivity by a disease-causing pathogen

Therapeutic vaccines: They fight the already occurred disease

For which diseases are vaccines available?

Vaccines and immunization is the most effective medical technique for preventing various infectious diseases. Globally immunization has caused the eradication (smallpox) and control of many diseases (polio, tetanus, and measles) in different countries. Vaccines that are part of immunization programs are proven effective against various infectious diseases, such as:

Chickenpox
Diphtheria
Influenza (flu)
Diphtheria
Hepatitis A
Hepatitis B
Human papilloma virus (HPV)
Haemophilus influenza type b (Hib)
Meningococcal infection
Measles
Mumps
Poliomyelitis (polio)
Pneumococcal infection
Rubella (German measles)
Rotavirus
Shingles (Herpes zoster)
Tetanus
Pertussis (whooping cough)
COVID-19 infection

How do vaccines work?

Vaccines are human-made biological agents and are a very effective and relatively safe way to fight infectious diseases. After vaccination, our immune system identifies vaccine pathogens as foreign agents and tries to destroy them. While fighting these foreign agents, our immune system remembers them, and when the disease-causing virulent attacks, our immune system responds accordingly.

Host-pathogen interaction and reaction in our body is a complicated process. After vaccination, our body produces antibodies against the weakened or attenuated pathogen. These antibodies generally take time (1 to 2 weeks) to develop in our system. During this time, we can still become infected. Once antibodies become active in our system, they provide immune protection against pathogens in the future.

The efficacy of the vaccine is dependent on several factors, such as:

Virulent disease as some vaccines performs better than others.
The virulent strain of vaccines as some vaccines are specific to a particular pathogen strain.
Strict adherence to the vaccination schedule
Idiosyncratic or no response to a vaccine as in some individuals antibodies against that particular infection do not develop.
Age of the person
Ethnicity as some people have a higher predisposition to a particular disease
Hereditary predisposition

Benefits of vaccination

Vaccines possess numerous benefits, including:

Vaccines protect us from many fatal diseases such as meningococcal disease and diphtheria
It also reduces the risk of spreading infection from vaccinated person to person around them
When sufficient people in a population develop immunity to an infectious disease, then the spread of disease halts due to the development of herd immunity (community immunity).
If someone still gets an infection after vaccination, the duration and symptoms reduce to a greater extent.
Vaccines also help in preventing the development of antibiotic resistance
Vaccines given to infants, children, pregnant ladies, or adults are safe. They generally do not cause any side effects or have minimal side effects like fever, pain at the injection site, or muscle pains. Vaccination provides disease-free life and improves the quality of life.

On this World Immunization Week, let’s raise awareness and increases the number of immunization against vaccine-preventable diseases globally.