The Office of Human Resources

Staying Up to Date on Vaccinations


Overview. The World Health Organization (WHO) estimates that between 3.5 and 5 million deaths are prevented each year by vaccinations for preventable but life-threatening diseases. Receiving recommended immunizations plays a crucial role in protecting one's health throughout a lifetime.

How Vaccines Work. Vaccines work by stimulating your immune system to produce antibodies, like it would if you had an infection. However, unlike bacteria and viruses, vaccines do not actually make you sick. There are two main types of immunity, active and passive:

  • "Active" immunity means you have antibodies against a particular germ. This can happen if you have had the infection in the past (this is called "natural immunity") or because you have received a vaccine that stimulated your immune system to produce the antibodies. Most vaccines induce active immunity.
  • "Passive" immunity comes from serum immune globulin, which provides temporary immunity with antibodies obtained from a large pool of donors. This approach offers short-term protection to people who have been exposed to a specific germ; it is not routinely recommended for individuals.
Another important term to understand is "herd immunity." This is when enough people are immune to a disease so that it can no longer spread easily between people. To get to herd immunity, enough people need to get vaccinated to protect those who cannot get vaccinated and to lessen transmission.

Side Effects. Often vaccines cause no side effects, but sometimes they do. Experiencing a side effect does not mean that you are sick, just that your immune system is responding to the vaccine. When side effects happen, they can include:
  • Redness, mild swelling, or soreness where you got the shot
  • Mild fever
  • Mild rash
  • Headache or body aches

Vaccines can sometimes cause more serious side effects, such as severe allergic reactions, but serious side effects are rare. Ask your doctor or nurse what side effects to expect each time you get a vaccine. If you have a reaction or a problem after a vaccine, let them know.

Vaccination Recommendations. There are some vaccines that all adults should get, even if they received their childhood vaccines. These vaccines protect against the following infections:
  • Coronavirus disease 2019 ("COVID-19") – This is an infection caused by a virus called SARS-CoV-2. It can cause a fever, cough, and trouble breathing, along with other symptoms. Some people get severely ill from COVID-19.
  • Influenza (flu) – The flu can cause fever, chills, muscle aches, cough, and sore throat. It can even cause a lung infection.
  • Pertussis – This infection is also known as "whooping cough" and can cause a severe breathing illness in babies. It can also make older children and adults sick. Vaccinating adults helps prevent babies around them from getting the infection. The pertussis vaccine comes in the same shot as the diphtheria and tetanus vaccines.
  • Diphtheria and tetanus – Vaccines against these 2 diseases are usually together in 1 shot, or in a shot with the pertussis vaccine. Diphtheria can cause a thick covering in the back of the throat that can lead to breathing problems. Tetanus causes the muscles to work abnormally.
  • Hepatitis B – This is a serious disease caused by a virus. It can cause long-term liver problems or liver cancer. The hepatitis B vaccine is recommended for all adults under age 60, and some adults age 60 and older.
Some adults will need other vaccines, depending on their age, medical conditions, jobs, travel plans, and other factors. These can include vaccines to protect against:
  • Pneumococcus – Pneumococcus is a germ that can cause an infection of the lungs, ears, blood, or tissues around the brain.
  • Meningococcus – Meningococcus is a germ that can cause an infection of the blood or tissues around the brain.
  • Herpes zoster, also called "shingles" – Shingles can cause a painful skin rash and blisters.
  • Human papillomavirus ("HPV") – There are different types of HPV. Depending on the type and where the infection is, HPV infection can lead to cancer of the cervix, vagina, penis, or anus. It can also cause genital warts or cancer of the mouth and throat. Most doctors recommend that people get the HPV vaccine at age 11 or 12. But people can get the vaccine any time from age 9 to 26.
  • Other infections – These include measles, chickenpox, hepatitis A, and respiratory syncytial virus ("RSV").


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