What is Immunization?

Immunization is the process of developing immunity or resistance in an individual against an infectious disease by administering a potent vaccine. Vaccines stimulate an individual’s immune system to protect the individual against subsequent disease or infection.

Moreover, immunization is an established way to control and eliminate infectious diseases that could be life-threatening. According to the World Health Organization (WHO), immunization is estimated to prevent between 2 to 3 million fatalities every year.

The process is commonly recognized as the most successful and cost-effective health interventions, with established strategies making it available to even the most hard-to-reach population as well as susceptible people.

World Immunization Week takes place every year during the last week of April from 24 to 30 April. Immunization Week is a worldwide public health campaign for increasing consciousness and rates of immunization against vaccine-preventable infections across the world. Immunization helps to protect millions of lives each year.

How Does Vaccination Work?

Vaccines are used for immunization of people against infectious diseases causing illness, serious disability or even death. In the human body, vaccines develop a defense mechanism against the disease. Thus, a vaccinated person for a specific condition is unlikely to get affected by the same disease again.  

Vaccines comprise of a similar virus or germ that is responsible for the infection. However, the virus in the vaccine has been inactivated, killed, or weakened so that it does not make people sick. Some vaccines contain only a portion of the virus. When a person gets immunized, the body is misled into thinking that it has been infected and the immune system makes antibodies to kill the viruses.

These antibodies remain in the body of a vaccinated person for a prolonged period and remember to fight the virus and hence prevent the infection. If the virus from the disease enters the immunized person’s body in the future, the antibodies kill the virus before the person can become sick.

Most of the individuals are completely protected against the infection after immunization. However, in a few cases, there are risks that people who are immunized could still get the infection because they are only partially protected from the vaccine. However, this is a rare condition and is only common in individuals with several medical conditions affecting the immune system. Vaccination is the best approach to prevent the spread of infectious diseases with no medical treatment.

Like drugs, vaccines also undergo different stages of clinical trials before receiving an approval for commercialization from the respective regulatory authorities. Vaccine candidates are initially given to healthy volunteers to ensure the candidate is safe to use.

What is Herd Immunity?

Immunization protects the infections and aids in preventing the spread of certain diseases in the larger population. When more individuals in a community are immunized, fewer people get sick because the virus has a fewer number of people to infect, and if someone does not have the infection, they cannot spread it further. Some people cannot get immunized, so ensuring that maximum people in a community are fully vaccinated will help protect the whole community, including those that cannot be vaccinated. This is known as herd immunity.

When no one is immunized, contagious diseases can spread in the community rapidly. However, when some people are immunized, the disease can affect a smaller group of people, those who are not protected. But, when most of the community gets immunized, very few community members will get the infection because of herd immunity. To achieve herd or community immunity against any infection, a community must have between 74-95% of the people immunized, depending upon the severity of the infection.

The individuals that might be vulnerable to diseases are known as susceptible, for instance, people with impaired or weak immune systems. These individuals might not be able to get vaccinations or may not build immunity even after having been vaccinated. In this case, the only protection against specific infections is for others to get vaccinated, so the diseases are less common.

To know whether herd immunity can help combat the ongoing COVID-19 pandemic, click here.

What are the Benefits of Immunization?

Immunization is the most simple and effective way of protecting people and community from any contagious disease. Immunization works by activating the immune system of the body to fight against specific diseases. If a vaccinated individual comes in contact with the viruses causing these diseases, their immune system is capable of responding more effectively.

A glance at the benefits of immunization-

• Immunization either prevents the disease from developing or reduces its severity.
• Immunization prevents people and community from getting infections for which there are no medical treatments. These infections can trigger serious complications and even mortality.
• If exposure to an infection occurs in a community, there is little to no risk of an epidemic if the individuals in the community have been immunized.
• Immunization can help to protect vulnerable or susceptive individuals from any contagious disease.

Difference between Immunization and Vaccination

Most of the times, both the terms immunization and vaccination are used interchangeably. However, their meanings are not precisely the same.

In vaccination, a potential vaccine is administered to the individual. Immunization is how the body reacts after the vaccine is administered.

A vaccine stimulates the immune system of the body so that it can recognize the infection and protect the vaccinated person from future diseases. After the immunization process, a person becomes immune to the viruses causing that infection.