Prevention is Better than Cure
- Desiderius Erasmus, a dutch philosopher had given this statement as far as the 1500s.
It all began in the 1800s when Edward Jenner, a British physician observed the mystery behind smallpox. He observed milkmaids who were exposed to cowpox were safe from smallpox. He inoculated the pus of cowpox into an eight-year-old boy following which the boy did not suffer from cowpox disease anymore. Subsequently, he discovered mild or no symptoms of smallpox in humans exposed to the pus of cowpox. This was the story of the first vaccine discovered and the beginning of the end for smallpox. Since then vaccines have been discovered for various other diseases saving millions of lives worldwide.
However, the term ‘Vaccine’ was coined later by Jenner himself. The term ‘Vaccination’ for getting a vaccine while the term ‘Immunisation’ refers to both vaccination and eventual immunity against the disease.
What type of immunity does Vaccine provide?
Humans have two types of immunity- active and passive immunity. Passive immunity can be obtained naturally from mother to children via breast milk, whereas artificial passive immunity is where antibodies against the disease are obtained from other organisms and are administered to fight against the disease. Active immunity is also divided into natural and artificial immunity. Natural active immunity is obtained by natural exposure to disease. Artificial active immunity is generated when the body is given a vaccination against the disease.
So when a body is exposed to a weakened or suboptimal dose of the disease-causing germs in the form of the vaccine, the body mounts an attack against these germs before causing a full-scale disease. The immunity generated mimics a natural infection and may confer lifelong immunity to the person. Sometimes booster doses of the vaccination are administered for better protection.
Types of Vaccine
1. Inactivated Vaccines- they contain killed germs to produce immunity. The immunity produced may not be as strong which is overcome with additional booster doses of the vaccine.
2. Live- attenuated Vaccines- contained weakened forms of the disease-causing germs hence causing a stronger immune response in comparison to other types of vaccines. However, physician advice should be taken in immunocompromised people as it may cause actual disease.
3. Subunit/ Recombinant/ Conjugate/ polysaccharide vaccine- These vaccines contain only a specific disease-causing part of the germs. No fear of actual disease in immunocompromised individuals. However, these vaccines will require booster doses for stronger immunity against the
4. Toxoid vaccines- They use the toxins created by the germs to create immunity. These vaccines require booster doses
5. Viral Vector vaccines- a new technology in vaccines where another unrelated modified virus is used to deliver an immune response against another disease.
6. mRNA vaccines- A new type of vaccine production. Here genome- mRNA is introduced in the form of a vaccine which causes the host to produce proteins of the germs in the body and trigger an immune response against the foreign protein. Since no live germs are used, the risk of disease in immunocompromised individuals is low.
As children, everyone receives various shots of vaccines for protection against common diseases prevalent in society. The government has put in place a Universal Immunization Programme (UIP) schedule so children receive vaccinations at the right time and prevent a wide variety of diseases. The health department strives hard to make sure that every child in the country receives the vaccines and stays protected against diseases.
The government of India is providing vaccination to prevent 11 vaccine-preventable diseases nationally, i.e. Diphtheria, Pertussis, Tetanus, Polio, Measles, a severe form of Childhood Tuberculosis and Hepatitis B and meningitis & pneumonia caused by Haemophilus influenza type B, and also rubella, rotavirus and Japanese encephalitis in selected states.
1. BCG vaccine:
It is a live attenuated vaccine, given as an intradermal injection. It provides protection against Tuberculosis(TB) meningitis or miliary diseases in the early years. It is given at birth or if missed can be given up to 1 year of age, preferably before exposure to a person with an active disease. Booster dose not required.
2. OPV ( oral polio vaccine)
It is a live attenuated vaccine given 2 drops orally. It protects against poliovirus type 2 and prevents polio paralytic attack. OPV- 0 dose is given at birth or within the first 15 days followed by booster doses number 1,2 and 3 at 6, 10 and 14 weeks after birth respectively till 5 years of age.
IPV( Injectable polio vaccine)
This was introduced in India in 2015 as part of the Global Polio Endgame strategy, given with OPV. It is an inactivated/ killed vaccine. Two fractional doses at 6 and 14 weeks of age are given as an intradermal injection in the right upper arm.
The Pulse Polio programme conducted every year was started with the objective of achieving a hundred percent coverage under the Oral Polio Vaccine.
3. Hepatitis B vaccine
It is a recombinant DNA vaccine given as an intramuscular injection. It prevents Hepatitis B liver disease. A Series of 3 shots are given at 0, 6 and 14 weeks or as part of pentavalent vaccines at 6, 10 and 14 weeks.
Adults and children can receive this vaccine’s first dose followed by 1 and 6 months for the second and third doses.
4. Pentavalent Vaccine-
Introduced in 2011 this provides vaccination against Hepatitis B, Diphtheria, Pertussis, Tetanus (DPT – previously trivalent vaccine) and Haemophilus influenza B(Hib). It is given intramuscularly at 6 weeks, 10 weeks & 14 weeks if missed can be given till one year of age.
It is a recombinant subunit type of vaccine providing protection against diphtheria, pertussis (whooping cough) and tetanus. Now currently part of the pentavalent vaccine given at 6, 10, 14 weeks followed by booster dose 1 at 16- 24 months of age and booster dose 2 at 5 to 6 years of
It is a toxoid vaccine protecting against the Influenza B virus. It is administered as an intramuscular injection. Now part of pentavalent vaccines and follows the same schedule.
Tetanus toxoid (TT) –
It is an inactivated toxin given as prevention against tetanus a severe form of the disease (muscle stiffness) in contact with Clostridium tetani bacteria present in the soil. It is given by intramuscular injection. Other than being part of, the pentavalent vaccine additional booster doses are given at 10 and 16 years of age, and also to pregnant women.
TT has been replaced with the Td vaccine which is given at 10 and 16 years of age and protects against tetanus and adult diphtheria. It is given intramuscularly in the upper arm.
5. Rotavirus vaccine-
It is a live attenuated virus given orally to prevent watery diarrhoea, fever and vomiting. It is given at 6, 10, and 14 weeks after birth (can be given till 1 year of age).
6. Pneumococcal conjugate vaccine-
It is a conjugate inactivated virus containing streptococcus pneumoniae. It prevents pneumonia, blood infection and bacterial meningitis. The vaccine will be given in two primary doses at 6 & 14 weeks of age followed by a booster dose at 9 months of age.
7. MR vaccine (MMR vaccine- IAP schedule)
It is an attenuated live virus vaccine administered as a subcutaneous injection giving protection against measles mumps and rubella viruses. The first dose is given at 9 completed months up to 12 months (can be given till 5 years of age). The second dose is given at 16-24 months. The 3rd dose is given at age 4 – 6 years (IAP vaccine schedule).
8. Japanese Encephalitis-
It is a live attenuated vaccine which prevents brain fever by a flavivirus. Administered as a subcutaneous injection. The first dose is given at 9 completed months up to 12 months. The second dose is given at 16-24 months. Mostly limited to endemic areas only.
9. Human Papilloma vaccine(IAP schedule)-
It is a subunit vaccine preventing anal vulva, vagina and oropharynx and cervical cancers and genital warts. It is not included in UIP. 2 doses at 6-month intervals at 9 to 14 years of age or 3 doses if more than 15 years of age at 0,1-2 and 6 months intervals, until the age of 45 years.
10. Varicella vaccine-
It is a live attenuated vaccine administered as a subcutaneous injection. It confers protection against chicken pox. The first dose is at 15 months after birth and 2nd at 4 – 6 years of age. Adults who never had chickenpox can take 2 doses of the vaccine 28 days part.
Vaccination provides protection against communicable infectious diseases. In turn, it protects indirectly those who are vulnerable to diseases. This is called “community immunity”. A healthy immune system equals a healthy body. Let us build a strong healthy community for the future by actively immunizing our upcoming generation.
“He who has health has hope, and he who has hope has everything” – ARAB PROVERB
N.B- 2 schedules are in use for immunisation in India- The National and IAP. This article has followed the National schedule and has discussed the other vaccines included in IAP.
About the Author:
Renisha Thomas is a student of 2 nd year B.Ed at St Aloysius Institute of Education, Mangaluru.