Immunity refers to the body's natural defense mechanism against diseases. An infant's immune system is underdeveloped at birth, making them more susceptible to infections. Vaccinations play a crucial role in diminishing the risk of infection by aiding the body's defenses to safely build immunity against diseases, thereby fortifying the immune system.

When harmful microorganisms, such as bacteria and viruses, invade the body, the child's immune system is activated. It performs the following functions:

- Identifies the invading microorganism as a foreign entity that doesn't belong to the body.
- Reacts by generating antibodies that target and neutralize the harmful germs.
- Retains memory of these microorganisms, enabling the antibodies to quickly respond to future invasions by the same germs, preventing illness before it starts.

Vaccines are pivotal in disease prevention because they introduce killed or weakened pathogens into the body. This exposure stimulates the immune system to mount a defensive response similar to actual infection. However, because vaccine pathogens are inactivated or attenuated, they do not cause illness. Instead, they train the immune system to recognize and combat these pathogens swiftly if encountered in the future. This results in immunity, shielding the individual from potential illness upon future exposure to the same germ.

Vaccines that have received licensure have undergone extensive testing to ensure they are safe for you and your child.

The practice of vaccinating infants serves as a crucial protective measure against numerous severe diseases that could result in lasting impairments or even death. Vaccinations play a vital role in preventing the spread of these diseases within communities. A higher vaccination rate significantly reduces the likelihood of disease transmission.

Tuberculosis (TB) is a grave infectious disease primarily targeting the lungs but can also spread to other body parts. To combat this disease, the BCG vaccine is administered, particularly to infants, as it has proven effective in reducing the incidence of tuberculosis. The administration of the BCG vaccine results in a minor raised bump, which heals over time, leaving a small scar.

Hepatitis B constitutes a significant health concern as a liver infection triggered by the Hepatitis B virus (HBV). This potentially fatal illness spreads through exposure to the blood or bodily fluids of someone infected with the virus or from a mother to her unborn child.

Diphtheria is a critical condition that often starts with a sore throat and can quickly evolve into complications with breathing. Without prompt treatment, it may adversely affect the heart and nervous system, potentially resulting in death.

Tetanus is another disease impacting the nervous system. It is characterized primarily by muscle spasms, lockjaw, and breathing difficulties. This condition is induced by neurotoxins from bacteria that enter the body through cuts and wounds.

Pertussis, commonly known as whooping cough, triggers prolonged periods of coughing that can severely limit one's ability to breathe. Infants under one year of age are particularly vulnerable to this disease, requiring hospital care upon diagnosis due to the high risk of mortality.

The poliovirus poses a high risk of contagion, transmitted through respiratory droplets from a cough or sneeze and contact with an infected individual's feces. Although a significant number of those infected by polio only experience symptoms akin to a mild flu, there is a grave possibility that it may result in permanent paralysis or muscle weakness if the spinal cord becomes infected.

The Hib vaccine is critical in preventing infections caused by the Haemophilus influenzae type B bacteria. These infections include serious conditions like septicemia, an infection of the bloodstream, pneumonia, an infection of the lungs, and meningitis, an infection of the protective membranes covering the brain and spinal cord. If left untreated, these illnesses can be fatal, highlighting the importance of vaccination.

Pneumococcal disease encompasses a variety of illnesses caused by the bacterium pneumococcus. This can include less severe infections like those in the sinuses and ears and more serious conditions like pneumonia, meningitis, and bloodstream infections. The disease can be transmitted from one person to another through coughing or sneezing, even in cases where the infected individual shows no symptoms.

The MMR vaccine is essential in safeguarding individuals from three potentially severe illnesses: measles, mumps, and rubella.

Measles, recognized for symptoms such as fever, cough, runny nose, eye irritation, and distinctive rashes, can lead to severe complications. These include ear infections, pneumonia, seizures, brain damage, and, in extreme cases, death.
Mumps presents symptoms like fever, headache, muscle pain, loss of appetite, and swollen glands. However, it can escalate to more severe complications such as deafness, meningitis, and infertility.
Rubella, commonly called German measles, manifests through rashes and fever. Of particular concern is the risk it poses to pregnant women, as contracting rubella during pregnancy can result in a miscarriage or severe congenital disabilities in the newborn.

Though these illnesses may seem manageable at first, they carry the potential for serious, life-altering complications. The MMR vaccine serves as a protective shield, safeguarding individuals and communities from these diseases' profound impacts.

Rotavirus is a highly infectious ailment that predominantly affects babies and young children. It often results in severe diarrhea and can also be accompanied by symptoms such as fever and vomiting. Given its severity, a rotavirus infection can lead to dehydration, necessitating hospitalization for the affected children.

Hepatitis A transmission occurs via the oral-fecal route, primarily from person to person or through ingesting contaminated food or water. This liver infection often manifests symptoms like fever, prolonged jaundice, headaches, and fatigue.

Chickenpox is a prevalent illness in childhood, though adults can also contract it. It results from the varicella-zoster virus. Those who are infected develop tiny, fluid-filled, and exceedingly itchy blisters. The virus has the potential to lie dormant within nerve cells, potentially reemerging years afterward as shingles, a condition known for its severe pain.

Influenza, commonly known as the flu, is a severe viral infection primarily affecting the respiratory system. It has the potential to cause significant health complications, including pneumonia and ear infections, and can exacerbate conditions such as asthma. Although the influenza vaccine does not offer complete protection against all virus strains, vaccinated individuals usually suffer from a less intense illness.

Meningococcal disease is a formidable infection triggered by specific bacteria. It culminates in two severe conditions: meningitis, which assaults the protective layers surrounding the brain and spinal cord, and septicemia, a dangerous form of blood poisoning. This ailment is attributed to various strains of meningococcal bacteria, notably types A, B, C, W, and Y. The transmission of the disease mirrors that of the common cold, occurring through respiratory droplets expelled during coughing and sneezing or through the exchange of saliva.

Japanese Encephalitis (JE) is a significant health concern that predominantly affects rural regions in Asia and the Western Pacific. This disease originates from the Japanese encephalitis virus (JEV), transmitted through the bite of nocturnal mosquitoes. These mosquitoes primarily prey on animals, including various dairy livestock, which act as reservoirs for the virus.

Vaccination should be postponed under certain conditions, including:

- If your baby is experiencing a high fever or a widespread infection of the skin,
- If your baby has a compromised immune system or there is suspicion of one,
- If the child's mother underwent immunosuppressive biological therapy during pregnancy,
- Additionally, a family history of immune system issues, including HIV, may also necessitate a delay in vaccination.

Following vaccinations, it is not uncommon for children to experience minor side effects, such as discomfort where the shot was given or the appearance of a rash. These responses are typical and tend to resolve quickly. Consult your child's healthcare provider for detailed information on the potential side effects associated with specific vaccines. Contact your healthcare provider immediately if you observe any atypical symptoms in your child post-vaccination.