Almost all children born in America have had a series of childhood immunizations. The oldest (and most successful) vaccine was against smallpox; so successful, in fact, that the disease responsible for some of the worst epidemics in history was declared fully eliminated from the world’s population, and vaccination was discontinued in 1983. Other vaccines continue to be given to all children, generally between birth and eighteen months of age. These include vaccines against measles, mumps, rubella (German measles), tetanus, diphtheria, pertussis (“whooping cough”), polio, and, more recently, newer vaccines against varicella (chicken pox), hepatitis B, and H. influenzae (a bacterial form of respiratory infection that may be especially severe in children).

Adults born and now living in the United States are most likely immune to many of these diseases, but there are exceptions, and it is these that will be discussed in the rest of this article. The following is a list of vaccines that many adults should consider receiving, always under the direction of a qualified health care provider.

1. Flu vaccine (Influenza). Every year, millions of people are infected with the flu virus around the world, and many deaths occur. Rates of illness and death from influenza are highest among adults aged 65 and over, as well as among persons of any age who have medical conditions that place them at high risk for medical complications. Since the flu virus tends to change (mutate) on a yearly basis, flu vaccine must be reformulated and re-administered annually. Additionally, the Center for Disease Control and Prevention recently lowered the age for universal vaccination from 65 to 50 years of age.

2. Td (Tetanus/Diphtheria). While most childhood vaccines provide lifelong immunity, a periodic booster dose for these two diseases is necessary. Many individuals receive booster doses after injuries that break the skin and may become infected with tetanus bacteria; nevertheless, it is a good rule to get a booster dose every ten years, even if no injury has occurred.

3. Hepatitis B Vaccine. This disease, one of several types of hepatitis, or liver infections is primarily transmitted in the same way as HIV/AIDS, that is, through sexual contact or intravenous drug use from sharing used needles. Persons who have the disease or have become chronic carriers of it may be unaware that they are infected, and may present no outward signs of infection. Individuals who have multiple or same-sex partners or who use intravenous drugs should have this vaccine. Persons working in the health care industry should also have the vaccine. Talk to your health care provider to see if you would benefit from having it.

4. Hepatitis A Vaccine. Another less serious liver infection, hepatitis A is spread primarily through contaminated food and water. This vaccine is now routinely recommended for children as well as adults living in certain high-risk areas or communities. Speak to your health care provider to see if you should have this vaccine.

5. Lyme Disease Vaccine. Much public attention has been given to this disease, caused by bacteria in ticks that live primarily on mice and deer. The ticks may then bite and infect humans. Although the disease can be treated with antibiotics, its vague symptoms often go undetected until it has caused serious harm. Persons who spend significant time outdoors either for work or recreation and live in areas where this disease is common should consider having the vaccine.

6. Pneumococcal Vaccine. This is a bacterium responsible for a type of pneumonia, and is most serious and life-threatening in persons over the age of 65, and in immune-compromised individuals (persons suffering from cancer or who have had their spleen removed, persons with AIDS and certain other chronic illnesses). This vaccine is generally recommended for all persons over the age of 65.

7. Varicella Vaccine. This new vaccine against common chicken pox is seldom indicated for adults, most of who had the disease as children. Persons who work in specific areas such as health care should consider varicella vaccine if a blood test does not detect protective antibodies.

There are many other vaccines available to protect against diseases that are not common in the United States, such as yellow fever, cholera, typhoid, plague and anthrax. Unless you are traveling to parts of the world where these diseases are common or are assigned to military service, these vaccines are not necessary. Always check with your personal health care provider to be certain which vaccines may be right for you. Remember that women who are pregnant or intending to get pregnant should not receive any vaccinations without the express consent of their attending health care provider.

Dr. Gehl is a clinical medical director of The New York City Department of Health.