May 13, 2022: The Centers for Disease Control and Prevention listed six Connecticut Counties in the High/Orange category as part of its COVID-19 Community Levels Map. Only Fairfield and New London Counties are listed in the Medium/Yellow category. Residents in these counties should wear a mask indoors in public; stay up to date with COVID-19 vaccines and get tested if they have symptoms. Additional precautions may be needed for residents who are at high risk for severe illness. Visit the CDC COVID-19 Community Levels Map for updates.

Public Information

group photo of adults, teens and babies

How Vaccines Prevent Disease

Most vaccine-preventable diseases are caused by germs that are called viruses or bacteria. Vaccines to help prevent these diseases generally contain weakened or killed viruses or bacteria specific to the disease. Vaccines help your body recognize and fight these germs and protect you each time you come in contact with someone who is sick with any of these diseases. There are a series of steps that your body goes through to develop immunity through vaccination:

  • First - a vaccine is given by a shot (influenza vaccine may be given by a nasal spray and rotavirus vaccine is given by mouth). 

  • Next - over the next few weeks your body makes antibodies and memory cells against the weakened or dead germs in the vaccine.

  • Then - the antibodies can fight the real disease germs if you are exposed to the germs and they invade your body. The antibodies will help destroy the germs and you will not become ill.

  • Finally - antibodies and memory cells stay on guard in your body for years after vaccination to safeguard you from the real disease germs.

  • Most vaccines are given to babies and young children, but some are needed throughout your lifetime to make sure you stay protected. This protection is called immunity. Vaccines are an important and safe way to keep you healthy. 


Childhood Immunization schedule for parents

Adolescent immunization schedule 

Parents: Vaccines For Your Children

Preteen and Teen Vaccines

HPV Vaccines

Are HPV vaccines safe? How is the safety of HPV vaccines monitored and evaluated in the United States? Find the answers to these and other important HPV vaccine safety-related questions at





For more information or to contact the Immunization Program, please call:
860-509-7929, during normal business hours, Monday-Friday 8:30am to 4:30pm


Return to Immunization Home Page

Return to DPH Home Page