Adult Immunization Status (AIS-E)

The percentage of persons 19 years of age and older who are up to date on recommended routine vaccines for influenza, tetanus and diphtheria (Td) or tetanus, diphtheria and acellular pertussis (Tdap), herpes zoster, pneumococcal disease, hepatitis B and coronavirus disease 2019 (COVID-19).

Why it Matters

This measure focuses on improving immunization rates for recommended routine vaccines for adults aged 19 years and older. This measure is based on the best available evidence which recommends vaccination against influenza, tetanus, diphtheria and pertussis, herpes zoster, pneumococcal disease, hepatitis B, and COVID-19 for adults 19 and older ^{[1, 2]}.

Despite the health and economic benefits of vaccines aligned with routine adult immunization schedules, vaccination rates among the U.S. adult population indicate an opportunity for improvement ^[3]. Estimates of national vaccination coverage are available through the National Health Interview Survey (NHIS), in which a sample of adults self-report receipt of vaccines. 2024 NHIS data indicate that:

• 4% of adults aged 19 and older reported receiving the influenza vaccine.
• 59% of adults 19 and older reported having received any tetanus toxoid-containing vaccination in the past 10 years, and 28.6% reported receiving the Tdap vaccine.
• 36% of adults 50 and older reported receiving one or more doses of any type of herpes zoster vaccine
• 64% of adults 65 and older reported receiving one or more doses of any type of pneumococcal vaccine.

Influenza is a serious disease that is characterized by a variety of symptoms related to the nose, throat and lungs that can range in severity and lead to hospitalization and death ^{[4, 5]}. Between 2010 and 2024, average annual burden of seasonal influenza is estimated to range between approximately 9.3–41 million illnesses, 120,000–710,000 hospitalizations and 6,300–52,000 deaths ^[6].

Routine adult immunization schedules recommend annual influenza vaccination for all people 6 months of age and older ^{[1, 2, 7]}. For people 19 years and older, any age-appropriate inactivated influenza vaccine (IIV) formulation or recombinant influenza vaccine (RIV) formulation are acceptable options. A 2023 study estimated that the incremental cost-effectiveness ratio of the influenza vaccine was approximately $95,000 per quality-adjusted life year (QALY) for all age and risk groups except for non-high risk adults 18–49 ^[8].

Tetanus infection is associated with the painful tightening of skeletal muscles. The resulting muscle spasms can cause fractures, difficulty breathing, arrhythmia and death [9]. Without intensive care, almost all cases of tetanus are fatal ^[10]. Diphtheria can present as a respiratory or cutaneous disease. Complications include myocarditis, which can lead to heart failure, and neuritis, which may temporarily paralyze motor nerves ^[11]. Death occurs in 5%–10% of cases. Acellular pertussis, also known as whooping cough, is a highly communicable respiratory infection characterized by a prolonged cough ^[12].

There are three types of combination vaccines that protect against diphtheria, tetanus and pertussis (or whooping cough), including DTaP, Td and Tdap. Routine adult immunization schedules recommend that, regardless of the interval since their last tetanus or diphtheria toxoid–containing vaccine, persons aged 19 and older who have never received a dose of Tdap should receive one dose ^{[1, 2]}. To ensure continued protection against tetanus and diphtheria, booster doses of either Td or Tdap should be administered every 10 years throughout life ^[13]. The incremental cost-effectiveness ratio of vaccinating adults 19–85 with one Tdap dose is estimated to range from $248,000 to $900,000 per QALY ^[14]. Among the 267 tetanus cases and 13 tetanus-related deaths reported from 2013–2022, only 16 cases were among adults who had been fully vaccinated ^[15]. While diphtheria was once a common cause of death in U.S. children and adolescents, the vaccine has now virtually eliminated the disease in the U.S. ^[16]. Similarly, before immunizations for pertussis were introduced in the 1940s, there were about 200,000 cases of pertussis annually ^[13]. Since widespread use of the vaccine, pertussis cases decreased by 75%. Administering the Tdap vaccine to adults helps prevent the spread of pertussis to infants and prevents hospitalizations ^[17].

Herpes zoster, or shingles, is a painful skin rash caused by reactivation of the varicella zoster virus ^[18]. After a person recovers from varicella infection (chickenpox), the virus stays inactive in the body and can reactivate years later. The most common symptom of herpes zoster is post-herpetic neuralgia, severe, debilitating pain at the site of the rash that has no treatment or cure; however, herpes zoster can also lead to serious complications of the eye, pneumonia, hearing problems, encephalitis or death ^[19]. In the U.S., there are 1 million new cases of herpes zoster each year; 1 of every 3 people will be diagnosed with herpes zoster in their lifetime. Between 1% and 4% of adults with herpes zoster are hospitalized for complications, and an estimated 96 deaths each year are directly caused by the virus [18]. In 2015, total medical costs in the U.S. from zoster were estimated to amount to $2.4 billion ^[20].

One type of zoster vaccine is currently recommended for older adults: the recombinant zoster vaccine (RZV) ^{[1, 2]}. The number of people needed to be vaccinated with the recombinant zoster vaccine to prevent one case of zoster ranged from 11–17, and to prevent one case of PHN, ranged from 70–187 ^[21].

Pneumococcal disease (e.g., pneumonia, bacteremia, meningitis) is a common cause of illness and death in older adults and persons with certain underlying conditions ^[22]. Pneumonia symptoms generally include fever, chills, pleuritic chest pain, cough with sputum, dyspnea, tachypnea, hypoxia tachycardia, malaise and weakness ^[23]. Bacteremia is a blood infection with a 20% mortality rate among all adults and a 60% mortality rate among older adults ^[23]. Meningitis symptoms may include headache, lethargy, vomiting, irritability, fever, nuchal rigidity, cranial nerve signs, seizures and coma and has a 22% mortality rate among adults ^[23]. Adult patients with pneumonia require hospitalization in nearly 10% of cases ^[24]. The annual aggregate economic burden of pneumococcal infections on the fee-for-service Medicare population is approximately $13 billion ^[25].

Pneumococcal disease vaccines have been shown to be highly effective in preventing invasive pneumococcal disease, and routine adult immunization schedules recommend that all adults 50 and older are vaccinated with pneumococcal conjugate vaccines ^{[1, 2, 26]}.

Hepatitis B is a liver disease that can manifest chronically where most people are asymptomatic or acutely with symptoms of fever, fatigue, loss of appetite, jaundice and body pains ^[27]. In 2023, there were an estimated 14,400 new cases of acute hepatitis B, 17,650 cases of newly-reported chronic hepatitis B and 1,769 hepatitis-B related deaths. Adults aged 40-59 years made up 48% of acute cases, and adults aged 30-49 made up 46% of chronic cases in 2023 ^[28].

Routine adult immunization schedules recommend universal hepatitis B vaccination for adults 19–59 years and adults aged 60 years and older with risk factors for hepatitis B ^{[1, 2]}. Adults 60 years and older without known risk factors for hepatitis B may also receive hepatitis B vaccines ^[29]. Universal vaccination against hepatitis B with the 3-dose series in adults has been shown to reduce acute cases by about 25% and about 23% of hepatitis-B related deaths. The 3-dose series has been associated with gains of approximately $152,722 per quality-adjusted life year (QALY), while the 2-dose series has been associated with gains of approximately $155,429 per QALY ^[30].

COVID-19 infection can lead to severe illness and death when left untreated ^[31]. Infection is characterized by symptoms related to the nose, throat, lungs and muscles ^[32]. For the 2024-2025 COVID-19 season, people 65 years of age and older had a cumulative hospitalization rate of 386.8 per 100,000 people ^[33]. As of June 1, 2024, nearly 1.2 million people have died of COVID-19 in the U.S. ^[34].

Administration of the COVID-19 vaccine can decrease overall health care costs by preventing severe disease and hospitalization ^[35]. Routine adult immunization schedules recommend the COVID-19 vaccination for all people 6 months of age or older whether or not they have ever previously been vaccinated with a COVID-19 vaccine ^{[1, 36, 2]}. At the end of 2022, it was estimated that COVID-19 vaccines prevented 18.5 million hospitalizations and 3.2 million deaths in the United States ^[37]. For adults 18-49 years of age, the incremental cost-effectiveness ratio for the 2023-2024 formulation of the COVID-19 vaccine was estimated to be $115,599 per QALY ^[38]. For adults 50-64 years of age, the incremental cost-effectiveness ratio of the 2023-2024 formulation of the vaccine was estimated to be $25,787 per QALY. For the 2024-2025 formulation, preliminary estimates of incremental cost-effectiveness ratios provide a societal perspective of $212,225 per QALY for 18-49 years, $113,248 per QALY for 50-64 years and $23,308 per QALY for people 65 and older ^[37].

Historical Results – National Averages