Why Vaccinations Are So Important

August is National Immunization Awareness Month (NIAM). This annual observance highlights the importance of vaccination for people of all ages, including babies and young children.


Vaccines prevent diseases that can be dangerous, even deadly. Although many of these diseases―including measles, mumps, polio, rubella, and whooping cough―are rare in this country, they still occur around the world and can be brought into the US, putting unvaccinated people at risk.


This article provides basic information on how vaccines work, vaccine risks/side effects, and vaccine safety. 


How Vaccines Prevent Diseases

Vaccines reduce the risk of a disease by working with the body’s natural defenses (the immune system) to help it safely develop protection (called “immunity”) to that disease.

Vaccines work by imitating a disease. This “imitation” infection does not cause illness. Instead, it causes the immune system to develop the same response it would to a real infection. This way, the body can recognize and fight the disease in the future. 


Types of Vaccines

Knowing which vaccines you need is an important step toward protecting your health and that of your family and friends. Getting vaccines on time helps prevent illness before you’re exposed. 


Vaccine schedules are designed with you in mind. They are constructed to be as safe and convenient as possible, without requiring unnecessary visits to your doctor or health care provider. 


Find out which vaccines you may need at different times in life by following the links below:

• Immunization Schedules for Infants and Children


• Immunization Schedules for Preteens and Teens


• Immunization Schedules for Adults



Vaccines and Children


Today, young children receive vaccines to protect them against 14 different diseases. The vaccination schedule is designed to protect young children before they are likely to be exposed to potentially serious diseases and when they are most vulnerable to serious infections. Because some vaccines require more than 1 dose, children can receive as many as 27 vaccinations by age 2, and up to 5 shots at 1 time. Parents may get upset or concerned when their baby gets several shots during a doctor’s visit. Some parents now ask their doctors to space out, separate, or withhold vaccines. Their concern that too many vaccines might overwhelm a child’s immune system is understandable, but the evidence that they don’t is reassuring (The Children’s Hospital of Philadelphia, Q&A Volume 3, Spring 2015).


Alison Keir, Nurse Leader at MGH Charlestown HealthCare Center’s Pediatric Department, says, “The reason we vaccinate is to keep a child healthy and safe from diseases that have been eradicated which can be life-threatening.”


Vaccine Side Effects & Risks

Like any medication, vaccines can cause side effects. Some people may experience minor symptoms, such as redness and swelling where the shot was given, or fever. These side effects are normal and go away within a few days. If you experience a reaction at an injection site, use a cool, wet cloth to reduce redness, soreness, and swelling.


Serious side effects following vaccination, such as severe allergic reaction, are very rare, and doctors and clinic staff are trained to deal with them. If you see something that concerns you, call your child’s doctor.



Some people choose not to immunize because they don’t want to risk experiencing side effects. But choosing not to immunize is not without risk. Not immunizing leaves a person vulnerable to contract the illness and suffer related problems. At the end of the day, when making an informed decision regarding your child’s health, review information from reputable sources and as always consult your doctor. 


Adapted from Center for Disease Control (CDC) “Making the Vaccine Decision”

This document is not a substitute for your care team's medical advice and should not be relied upon for treatment for specific medical conditions.