Nearly everyone should get vaccinated, from infants starting at two months old through adults well into their 70s and beyond. The specific vaccines you need depend on your age, health status, occupation, and travel plans. Here’s a practical breakdown of who needs what and when.
Infants and Children
Vaccination begins early because many dangerous diseases pose the greatest risk to the youngest children. The first doses of several vaccines are given at two months of age, with additional doses spaced out over the following years to build strong, lasting immunity.
The core childhood vaccines follow a predictable pattern. Protection against diphtheria, tetanus, and whooping cough requires five doses: at 2, 4, and 6 months, then boosters at 15 to 18 months and again at 4 to 6 years. Polio vaccination follows a four-dose series at 2, 4, and 6 to 18 months, with a final dose at 4 to 6 years. The measles, mumps, and rubella (MMR) vaccine is a two-dose series, with the first dose at 12 to 15 months and the second at 4 to 6 years.
Beyond these, children also receive vaccines against hepatitis A, hepatitis B, chickenpox, rotavirus, and several types of bacterial meningitis during their first few years. Most of these are completed before a child starts school.
Preteens and Teens
The HPV vaccine is one of the most important vaccines introduced during adolescence. It prevents cancers caused by human papillomavirus and can be started as early as age 9. For those who begin the series between ages 9 and 14, only two doses are needed, spaced 6 to 12 months apart. Starting at 15 or older requires three doses. The vaccine is routinely recommended through age 26 for anyone who wasn’t adequately vaccinated earlier.
Preteens also receive a tetanus, diphtheria, and whooping cough booster (Tdap), typically around age 11 or 12, along with meningococcal vaccines to protect against bacterial meningitis. These are especially important before college, where close living quarters increase transmission risk.
Adults Ages 19 to 49
Adults need vaccines too, not just the ones they remember from childhood. Every adult should get a flu shot annually and stay current on COVID-19 vaccination. A Tdap booster is recommended every 10 years to maintain protection against tetanus and whooping cough.
If you were born in 1957 or later and never received the MMR vaccine or don’t have documented immunity, you need one or two doses depending on your situation. Adults born in 1980 or later who haven’t had chickenpox or the vaccine need two doses of the varicella vaccine. Hepatitis A and hepatitis B vaccines are also recommended for adults who haven’t been previously vaccinated.
Adults between 27 and 45 who missed the HPV vaccine can still get it on a three-dose schedule, though the greatest benefit comes from vaccination before any exposure to the virus.
Adults 50 and Older
Turning 50 opens the door to the shingles vaccine, a two-dose series spaced 2 to 6 months apart. About one in three people will develop shingles in their lifetime, and the risk climbs with age. The vaccine is highly effective at preventing both the painful rash and the lingering nerve pain that can follow.
Adults 65 and older who haven’t previously received a pneumococcal vaccine (or whose vaccination history is unknown) should get one dose of a pneumococcal conjugate vaccine. Younger adults with chronic conditions like diabetes, heart disease, or lung disease also qualify. This age group should also pay attention to RSV vaccination, which became available for adults 60 and older to help prevent severe respiratory illness.
Older adults benefit from higher-dose or specially formulated flu vaccines designed to overcome the natural decline in immune response that comes with aging.
Pregnant People
Two vaccines are particularly important during pregnancy. A flu shot using an inactivated or recombinant vaccine is recommended during any trimester, ideally before flu season starts. The live-attenuated nasal spray version is not approved for use during pregnancy.
The Tdap vaccine is recommended during each pregnancy, typically given in the third trimester. This transfers protective antibodies to the baby, providing crucial defense against whooping cough during the first weeks of life before the infant can be vaccinated directly. RSV vaccination during pregnancy is also now an option to help protect newborns from severe respiratory illness in their first months.
People With Weakened Immune Systems
If you have HIV, are undergoing cancer treatment, or have received an organ or bone marrow transplant, your vaccination needs are different in two important ways: some vaccines are more urgent for you, and some must be avoided or delayed.
Live vaccines, which contain weakened forms of a virus, pose a risk when your immune system can’t keep even a weakened virus in check. People living with HIV can receive the MMR vaccine as long as their immune function (measured by a specific type of white blood cell count) has been stable for at least six months. But the combined measles-mumps-rubella-varicella vaccine should not be given to anyone with HIV.
Cancer patients whose disease is in remission and who have been off chemotherapy for at least three months can generally receive live vaccines again. Bone marrow transplant recipients need to wait at least 24 months before receiving MMR or chickenpox vaccines, and only if they don’t have graft-versus-host disease and their immune function has recovered.
The shingles vaccine, normally reserved for adults 50 and older, is recommended starting at age 19 for anyone who is or will be immunocompromised. For these individuals, the two doses can be given just 1 to 2 months apart instead of the usual 2 to 6 months, allowing faster protection before immune-suppressing treatment begins.
Healthcare Workers
People who work in hospitals, clinics, or other medical settings face higher exposure to infectious diseases and can transmit infections to vulnerable patients. Hepatitis B vaccination with confirmed immunity is required for hospital employees in several states. Annual flu vaccination is mandatory for all healthcare workers in some jurisdictions, such as Rhode Island, though policies vary by state.
Healthcare workers are also expected to have documented immunity to measles, mumps, rubella, and chickenpox, and to stay current on Tdap and COVID-19 vaccines. These requirements protect both the worker and the patients they care for.
International Travelers
Travel to certain parts of the world requires vaccines you wouldn’t normally need at home. Yellow fever vaccination is recommended for travelers to parts of South America and Africa and must be given at least 10 days before arrival, as some countries require proof of vaccination for entry. Typhoid vaccination is recommended for travel to countries where the disease is common. The injectable version needs at least two weeks of lead time, while the oral version requires four doses taken over a week, completed at least 10 days before departure.
Hepatitis A vaccination is recommended for most international travelers, with at least one dose given before the trip. A second dose, given six or more months later, completes the series for long-term protection. Depending on your destination, you may also need vaccines for rabies, Japanese encephalitis, or cholera.
When Vaccination Should Be Delayed or Avoided
Very few medical conditions are true reasons to skip vaccination entirely. The most clear-cut is a severe allergic reaction (anaphylaxis) to a previous dose of a vaccine or to one of its ingredients. If you’ve had this type of reaction, that specific vaccine should not be given again.
A moderate or severe illness with or without fever is a reason to postpone vaccination until you’ve recovered. A mild cold or low-grade fever, however, is not a reason to delay. The goal is to make sure your body can mount a proper immune response and that any new symptoms aren’t confused with a vaccine reaction.
Certain live vaccines are off-limits during pregnancy and for people with severely weakened immune systems, as described above. But inactivated vaccines remain safe and important for these groups. If you’re unsure whether a health condition affects your eligibility for a specific vaccine, your medical records and immune status are the key factors that determine which vaccines are appropriate and when.