First vaccines

Edward Jenner was the first to test a method to protect against smallpox in a scientific manner. He did his study in 1796, and although he did not invent this method, he is often considered the father of vaccines because of his scientific approach that proved the method worked.

The method Jenner tested involved taking material from a blister of someone infected with cowpox and inoculating it into another person’s skin; this was called arm-to-arm inoculation. However, by the late 1940s, scientific knowledge had developed enough, so that large-scale vaccine production was possible and disease control efforts could begin in earnest.

The next routinely recommended vaccines were developed early in the 20th century. These included vaccines that protect against pertussis (1914), diphtheria (1926), and tetanus (1938). These three vaccines were combined in 1948 and given as the DTP vaccine.

Late 1940s | Recommended Vaccines

Smallpox
Diphtheria*
Tetanus*
Pertussis*
* Given in combination as DTP

The vaccine everyone was waiting for — polio vaccine

Parents were scared of the polio epidemics that occurred each summer; they kept their children away from swimming pools, sent them to stay with relatives in the country, and clamored for an understanding of the spread of polio. They waited for a vaccine, closely following vaccine trials and sending dimes to the White House to help the cause. When the polio vaccine was licensed in 1955, the country celebrated, and Jonas Salk, its inventor, became an overnight hero.

Late 1950s | Recommended Vaccines

Smallpox
Diphtheria*
Tetanus*
Pertussis*
Polio (IPV)
* Given in combination as DTP

More vaccines followed in the 1960s — measles, mumps and rubella

In 1963, the measles vaccine was developed, and by the late 1960s, vaccines were also available to protect against mumps (1967) and rubella (1969). These three vaccines were combined into the MMR vaccine by Dr. Maurice Hilleman in 1971.

Late 1960s | Recommended Vaccines

Smallpox
Diphtheria*
Tetanus*
Pertussis*
Polio (OPV)
Measles
Mumps
Rubella
* Given in combination as DTP

The 1970s — vaccine success

During the 1970s, one vaccine was eliminated. Because of successful eradication efforts, the smallpox vaccine was no longer recommended for use after 1972. While vaccine research continued, new vaccines were not introduced during the 1970s.

Late 1970s | Recommended Vaccines

Diphtheria*
Tetanus*
Pertussis*
Polio (OPV)
Measles**
Mumps**
Rubella**
* Given in combination as DTP
** Given in combination as MMR

Vaccine development in the 1980s — hepatitis B and Haemophilus influenzae type b

The vaccine for Haemophilus influenzae type b was licensed in 1985 and placed on the recommended schedule in 1989. When the schedule was published again in 1994, the hepatitis B vaccine had been added.

The hepatitis B vaccine was not new, as it had been licensed in 1981 and recommended for high-risk groups such as infants whose mothers were hepatitis B surface antigen positive, healthcare workers, intravenous drug users, homosexual men and people with multiple sexual partners. However, immunization of these groups didn't effectively stop transmission of hepatitis B virus. That’s because about one-third of patients with acute disease were not in identifiable risk groups. The change of recommendation to immunize all infants in 1991 was the result of these failed attempts to control hepatitis B by only immunizing high-risk groups. Following this recommendation, hepatitis B disease was virtually eliminated in children less than 18 years of age in the United States.

1985 - 1994 | Recommended Vaccines

Diphtheria*
Tetanus*
Pertussis*
Measles**
Mumps**
Rubella**
Polio (OPV)
Hib

1994 - 1995 | Recommended Vaccines

Diphtheria*
Tetanus*
Pertussis*
Measles**
Mumps**
Rubella**
Polio (OPV)
Hib
Hepatitis B
* Given in combination as DTP
** Given in combination as MMR

Annual updates to the immunization schedule — 1995 to 2010

As more vaccines became available, an annual update to the schedule was important because of changes that providers needed to know, such as detailed information about who should receive each vaccine, age(s) of receipt, number of doses, time between doses, or use of combination vaccines. New vaccines were also added.

Important changes to the schedule between 1995 and 2010 included:

• New vaccines: Varicella (chickenpox - 1996), rotavirus (1998-1999; 2006, 2008); hepatitis A (2000); pneumococcal vaccine (2001)
• Additional recommendations for existing vaccines: influenza (2002); hepatitis A (2006)
• New versions of existing vaccines: acellular pertussis vaccine (DTaP ,1997); intranasal influenza (2004)
• Discontinuation of vaccine: Oral polio vaccine (2000)

2000 | Recommended Vaccines

Diphtheria*
Tetanus*
Pertussis*
Measles**
Mumps**
Rubella**
Polio (IPV)
Hib
Hepatitis B
Varicella
Hepatitis A

2005 | Recommended Vaccines

Diphtheria*
Tetanus*
Pertussis*
Measles**
Mumps**
Rubella**
Polio (IPV)
Hib
Hepatitis B
Varicella
Hepatitis A
Pneumococcal
Influenza

2010 | Recommended Vaccines

Diphtheria*
Tetanus*
Pertussis*
Measles**
Mumps**
Rubella**
Polio (IPV)
Hib
Hepatitis B
Varicella
Hepatitis A
Pneumococcal
Influenza
Rotavirus
* Given in combination as DTaP
** Given in combination as MMR

The schedule from 2011 to Present

Annual updates to both the childhood and adult immunization schedules offer guidance to healthcare providers in the form of new recommendations, changes to existing recommendations, or clarifications to assist with interpretation of the schedule in certain circumstances. The schedules are reviewed by committees of experts from the Centers for Disease Control and Prevention, the American Academy of Pediatrics, and the American Academy of Family Physicians.

Important changes to the schedule:

• New vaccines: meningococcal serogroup B vaccine (2014); COVID-19 (2021-2022)†
• Additional recommendations for existing vaccines: HPV (2011 to routinely vaccinate males), intranasal influenza vaccine (2018 again recommended)
• Discontinuation of vaccine: intranasal influenza vaccine (2016)

^†COVID-19 vaccines were recommended during the pandemic for increasingly younger age groups starting in late 2020. They were recommended for 5- to 11-year-olds in 2021, but they were not recommended for those younger than 5 years of age until 2022. COVID-19 vaccine was not added to the immunization schedule until 2023.

2020 | Recommended Vaccines

Diphtheria*
Tetanus*
Pertussis*
Measles**
Mumps**
Rubella**
Polio (IPV)
Hib
Hepatitis B
Varicella
Hepatitis A
Pneumococcal
Influenza
Rotavirus
* Given in combination as DTaP
** Given in combination as MMR

Combination vaccines

In the early 1950s, four vaccines were available: diphtheria, tetanus, pertussis and smallpox. Because three of these vaccines were combined into a single shot (DTP), children received five shots by the time they were 2 years old and not more than one shot at a single visit.

By the mid-1980s, seven vaccines were available: diphtheria, tetanus, pertussis, measles, mumps, rubella and polio. Because six of these vaccines were combined into two shots (DTP and MMR), and one, the polio vaccine, was given by mouth, children received five shots by the time they were 2 years old and not more than one shot at a single visit.

Since the mid-1980s, many vaccines have been added to the schedule. The result is that the vaccine schedule has become more complicated than it once was, and children are receiving far more shots than before (see Vaccine Safety for answers to the questions: "Are vaccines safe?"; “Do vaccines weaken the immune system?” and more). Now, children could receive as many as 27 shots by 2 years of age and up to six shots in a single visit. However, in the same way that the DTaP and MMR vaccines were combined, new combinations are being made to reduce the number of shots. Used in different age groups of children, the following combinations of vaccines are now available:

• Diphtheria, tetanus and acellular pertussis
• Diphtheria, tetanus, acellular pertussis, and inactivated polio
• Diphtheria, tetanus, acellular pertussis, inactivated polio and hepatitis B
• Diphtheria, tetanus, acellular pertussis, inactivated polio and Haemophilus influenzae type b
• Diphtheria, tetanus, acellular pertussis, inactivated polio, Haemophilus influenzae type b, and hepatitis B
• Measles, mumps and rubella
• Measles, mumps, rubella, and varicella
• Hepatitis A and hepatitis B (only for those 18 years of age and older)

Vaccines for Adolescents: A new generation of vaccines

Adolescents, like adults, were recommended to get tetanus boosters every 10 years; most requiring their first booster dose around age 11. Other than this, however, most adolescents did not require additional vaccines unless they missed one in childhood. By 2005, vaccines specifically recommended for adolescents were only recommended for sub-groups based on where they lived or medical conditions that they had. However, a new group of vaccines became available in the latter part of the decade.

• New vaccines: Tdap, 2005, meningococcal conjugate (2005), HPV (2006 females, 2009 males), meningococcal serogroup B vaccine (2014); dengue (2021); COVID-19 (2020-2021)^†
• Additional recommendations for existing vaccines: HPV (2011 to routinely vaccinate males), intranasal influenza vaccine (2018 again recommended)
• New versions of existing vaccines: HPV (protecting against 9 types, 2015)
• Discontinuation of vaccine: intranasal influenza vaccine (2016)

^†COVID-19 vaccines were recommended during the pandemic for increasingly younger age groups starting in late 2020. They were recommended for those 16 years and older in late 2020, but they were not recommended for 12- to 15-year-olds until 2021. COVID-19 vaccine was not added to the immunization schedule until 2023.

2000

Recommended Vaccines
Td

Catch-up
MMR
Hepatitis B
Varicella

Sub-groups
Hepatitis A

2005

Recommended Vaccines
Tdap

Catch-up
MMR
Hepatitis B
Varicella

Sub-groups
Hepatitis A
Pneumococcus
Influenza

2010

Recommended Vaccines
Tdap
HPV
Meningococcal conjugate (serogroups A,C,W,Y)
Influenza

Catch-up
MMR
Hepatitis B
Varicella
Polio

Sub-groups
Hepatitis A
Pneumococcus

2020

Recommended Vaccines
Tdap
HPV
Meningococcal conjugate (serogroups A,C,W,Y)
Influenza
Meningococcal serogroup B

Catch-up
MMR
Hepatitis B
Varicella
Polio

Sub-groups
Hepatitis A
Pneumococcus

Vaccines for adults — increasing opportunities for health

Historically, vaccines were deemed to be “only for children.” However, vaccines for adults are becoming increasingly common and necessary. Most adults think only of the tetanus booster recommended every 10 years and even then, many adults only get the vaccine if they injure themselves. In 2005, the Tdap vaccine was licensed as an improved version of the typical tetanus booster, Td. The newer version also contains a component to protect against pertussis (whooping cough). All adults, especially those who are going to be around young infants, should get the Tdap vaccine. Adults often unwittingly pass pertussis to young infants for whom the disease can be fatal. In 2012, the CDC recommended that pregnant women get a dose of Tdap during each pregnancy between 27 and 36 weeks gestation. In 2019, the CDC recommended that Tdap or Td vaccine could be used for booster dosing every 10 years.

Influenza vaccines, available since the 1940s, are now recommended for most adults. Vaccines like MMR and chickenpox are recommended for adults who have not had the diseases, and vaccines including hepatitis A, pneumococcus, and meningococcus are recommended for sub-groups of the adult population. The HPV vaccine became available in 2006. In 2018, the license was expanded to include people up to 45 years of age. In 2022, recommendations for expanded use of hepatitis B vaccine included all adults through 59 years of age who had not previously been vaccinated.

The first shingles vaccine, Zostavax, was licensed in 2006; a second shingles vaccine, Shingrix, licensed in 2017, produces a more robust immune response than Zostavax did. Two doses of this vaccine, separated by two to six months, are recommended for people 50 years and older. In 2019, Zostavax was no longer available.

In late 2020, the first COVID-19 vaccines were approved for use in response to the COVID-19 pandemic. Most adults were recommended to get this vaccine, but limited supplies required adults to be assigned to eligibility groups in order to protect those most at risk first. COVID-19 vaccine was not added to the immunization schedule until 2023.

In 2023, the first vaccines against respiratory syncytial virus (RSV) became available for adults 60 years of age and older.

Unlike childhood vaccines, which are often required for entrance to schools, adult vaccines are typically not mandated. However, people with certain occupations may be required to get vaccinated as a condition of employment. Most often, this occurs in the military and in healthcare-related occupations, but other industries may also require employment-based vaccinations. Limited requirements and a lack of preventive healthcare by most adults have led to low levels of vaccine use by adults.

The first formal adult immunization schedule was published in 2002 and is updated annually.

Learn more about the vaccine schedule for adults.