India observes its National Vaccination Day on March 16 every year. It is celebrated to raise awareness of the importance of vaccination and to remind people of past achievements in vaccination drives.
Vaccines work by injecting dead, inactive or partial viruses or bacterial toxins into your body to let your antibodies identify them as a threat so the next time an active virus enters your body, they fight.
While natural immunity is longer lasting than immunization, it also carries a greater risk of being infected. Vaccines are made to fight off the uninvited pathogens in your body and they work better.
Different diseases progress at different speeds in the body and booster shots serve as a reminder to your immune system to continue fighting them.
Studies show that babies can handle multiple vaccines at the same time as it depends on the babies' ability to generate an immune response. Even if the mother has been vaccinated, the baby has to get a dose.
Unlike other pathogens, the flu virus is susceptible to change every year. The strains of the influenza virus evolve to adapt to their survival. You will get protection against a new batch of viruses yearly.