Key Takeaways
- Several recommended adult vaccines—including Tdap, shingles, and pneumococcal—are widely under-administered.
- Immunity from childhood vaccines and earlier boosters can wane significantly over time.
- Annual flu vaccination and COVID-19 updated doses remain important for most adults every year.
- Age, health status, and occupation can all affect which vaccines an individual needs.
- A primary care provider is the best resource for identifying and filling personal immunization gaps.
Why Adult Vaccines Fall Through the Cracks
Most Americans associate vaccines with childhood doctor visits — a rite of passage that ends somewhere around adolescence. But immunity is not a permanent state. Protection from both childhood immunizations and earlier adult boosters can diminish over years or decades, leaving adults quietly vulnerable to preventable diseases. The CDC's Advisory Committee on Immunization Practices (ACIP) publishes an annual adult immunization schedule precisely because the need for vaccines doesn't stop at age 18. For a full overview of that schedule, see the U.S. Adult Immunization Schedule, decoded.
Busy lives, the absence of a single annual reminder system, and a general perception that vaccines are for kids all contribute to low uptake. The result: millions of adults are under-protected against infections that can cause serious complications. The list below covers the vaccines adults most commonly let lapse — and what the evidence says about each.
Tdap (Tetanus, Diphtheria, and Pertussis)
Most adults received a tetanus-containing vaccine as children, but protection against tetanus and diphtheria fades. ACIP recommends a Td (tetanus-diphtheria) booster every 10 years throughout adulthood. The Tdap formulation, which adds pertussis (whooping cough) coverage, should replace one Td booster if an adult has never received it. Pertussis has seen periodic resurgences in the U.S., making this booster particularly important for adults who have close contact with infants, who are most vulnerable to severe complications.
Tetanus and whooping cough protection fades — a Tdap booster every decade is a CDC standard recommendation.
Influenza (Flu)
Annual flu vaccination is recommended for virtually all adults. Influenza viruses mutate each season, meaning last year's vaccine does not reliably protect against this year's circulating strains. Despite widespread awareness, flu vaccination rates among U.S. adults remain below public health targets. Influenza can cause serious complications — including pneumonia, hospitalization, and death — particularly in adults over 65, pregnant individuals, and those with chronic health conditions. Getting vaccinated each fall remains one of the most impactful routine preventive measures available.
Flu viruses change every season — last year's vaccine is not enough protection for this year.
COVID-19 (Updated Doses)
COVID-19 vaccine recommendations have evolved as the virus and available vaccines have changed. ACIP currently recommends that most adults receive an updated COVID-19 vaccine dose annually, with the formulation adjusted to better match circulating variants. Some adults — particularly those who are older or immunocompromised — may be eligible for additional doses. Because guidance is updated regularly, checking with a provider or the CDC's current schedule is the most reliable way to know where you stand.
Updated COVID-19 vaccine formulations are designed to match circulating variants — annual dosing is widely recommended.
Shingles (Zoster)
Shingles is caused by the reactivation of the varicella-zoster virus — the same virus that causes chickenpox. Anyone who has had chickenpox carries the virus in their nervous system and is at risk for shingles later in life. ACIP recommends the recombinant zoster vaccine (RZV) for adults 50 and older, administered as a two-dose series. Shingles can cause severe, prolonged nerve pain (postherpetic neuralgia) that significantly affects quality of life. Despite the vaccine being highly effective, uptake among eligible adults remains lower than health authorities consider adequate. Immune function shifts with age, which is part of why shingles risk increases after 50.
Shingles vaccine is recommended at 50 — the nerve pain it prevents can be debilitating and long-lasting.
Pneumococcal Vaccines
Pneumococcal bacteria can cause pneumonia, meningitis, and bloodstream infections. ACIP recommends pneumococcal vaccination for all adults 65 and older, as well as for younger adults with certain medical conditions (such as chronic lung disease, diabetes, or immunocompromising conditions). The vaccine landscape for pneumococcal disease has evolved, with newer higher-valent formulations offering broader protection. A provider can help determine which vaccine or combination of vaccines is appropriate based on age and health status.
Pneumococcal vaccination is standard at 65 and earlier for adults with qualifying health conditions.
Hepatitis B
Hepatitis B vaccination became routine for infants in the early 1990s, which means many adults born before that era were never vaccinated. ACIP now recommends hepatitis B vaccination for all adults through age 59, and for adults 60 and older based on individual risk assessment and preference. Chronic hepatitis B infection can lead to cirrhosis and liver cancer, making this an important gap to close for unvaccinated adults. A simple blood test can determine prior immunity or infection status before vaccination.
Adults born before the 1990s often missed routine hepatitis B vaccination — many remain unprotected today.
Taking the Next Step
Catching up on missed vaccines is straightforward in most cases. A primary care provider can review your immunization history, cross-reference it with current ACIP guidelines, and identify any gaps. If you're unsure what shots you've received, tracking down your immunization records is a practical first step — state immunization registries are often a reliable source.
Adults managing chronic conditions such as diabetes, heart disease, or immunosuppression may have additional or modified vaccine recommendations; vaccination and chronic illness explores how underlying health factors can shape those decisions. And for adults 65 and older, vaccines are just one component of a broader preventive care picture covered in the comprehensive overview of preventive care for older adults.
Bring Your Records to Every Appointment
Carrying a current record of your immunizations — even a photo on your phone — helps any provider quickly identify gaps without relying on incomplete memory. Many states maintain immunization registries that can supplement personal records. Keeping this documentation current is a low-effort habit with meaningful long-term benefit.
This article is for general informational purposes only and does not constitute medical advice. Talk with a qualified healthcare provider about your personal immunization needs before making any health decisions.