Day of Immunology—April 29, 2022

The International Day of Immunology, observed annually on April 29, is dedicated to increasing global awareness of the importance of immunology in the fight against infection, autoimmunity, and cancer. The theme for 2022 is Vaccines. 

To celebrate, AAI launched a month-long education campaign with the goal of reaching 1.3 million Americans. The campaign demonstrated that, throughout history, vaccines have been responsible for saving lives and ending epidemics, pandemics, and major outbreaks of disease—and immunologists have played and continue to play a major role in giving us these vaccines.

We invite you to read the stories below of these life-saving vaccines and the immunologists (and AAI members) who were responsible for their development.

Learn how vaccines are approved today!

#ThankYouImmunology #DayofImmunology


Polio is a virus that can attack and destroy nerve cells in the spinal cord, causing paralysis and even death. In the early 20th century, polio brought fear to families around the world as it attacked mainly young children and, by the late 1940s, disabled an average 35,000 Americans per year.

Jonas Salk developed an injectable polio vaccine in 1953 that created antibodies protecting against the polio virus. Salk’s vaccine was the beginning of lives being saved from polio. Albert Sabin was responsible for developing an oral polio vaccine, which produced better immunity than injected polio vaccine and was given in a sugar cube. The oral vaccine was easier to distribute and administer for millions of people around the globe. Sabin’s research and vaccine increased mass use and brought immunity internationally.

Thanks to Salk and Sabin, the United States has been polio free since 1979, and polio is endemic in only two countries now (Afghanistan and Pakistan).


As we approach International Day of Immunology on April 29th, we are highlighting heroes of immunology who have profoundly changed and saved lives throughout history. Today, we recognize Anna Wessels Williams, who began her career as an immunologist at a time when very few women entered science.

In 1894, Williams volunteered at New York City Department of Health's diagnostic laboratory, working closely with director William H. Park on his projects to develop a diphtheria antitoxin. At the time, diphtheria was the sixth-highest cause of death in the United States, and New York City had already suffered from two major diphtheria epidemics that collectively killed more than 9,000 citizens. Williams was able to isolate a strain of the diphtheria, named the Park-Williams strain, a discovery crucial to the development of an antitoxin for the disease. It was issued to New York physicians for free to help eradicate the disease amongst the poor. Her work was foundational for the later development of a diphtheria vaccine.

Williams went on to make many significant discoveries related to rabies, scarlet fever, and trachoma—her work was so wide ranging that she literally wrote the book on "Who’s Who Among the Microbes."


As we approach International Day of Immunology on April 29th, we are highlighting heroes of immunology who have profoundly changed and saved lives throughout history. Today, we celebrate Maurice Hilleman, the immunologist who created the Measles, Mumps, and Rubella (MMR) vaccine, and is credited with creating 40 other vaccines, including those for Japanese B encephalitis, chicken pox, Hepatitis A, and Hepatitis B.

Measles, mumps, and rubella cause serious illness such as swollen lymph nodes, deafness, infertility, and even proved to be fatal. Mumps is linked to causing meningitis due to swelling in the spinal cord, so finding a cure was critical.

When Hilleman’s daughter Jeryl Lynn came down with mumps, he swabbed her throat for a sample and used that sample to begin developing a mumps vaccine. By culturing the pathogen in chicken embryo cells, Hilleman reduced the virus’s ability to harm humans to the point where it would produce immunity but not illness.

Hilleman’s other daughter Kirsten was one of the first children to get the vaccine in a trial run, which proved to be successful. Thanks to Hilleman's decision to safely store Jeryl Lynn’s sample for future study, the vaccine has saved millions of people from the harmful side effects of mumps, measles, and rubella.


As we approach International Day of Immunology on April 29th, we are highlighting heroes of immunology who have profoundly changed and saved lives throughout history. Today, we celebrate two immunologists who together created the vaccine that protects infants and children from type b Haemophilus influenza, also known as Hib.

Hib is a bacterial infection that can cause severe illness such as fevers, seizures, difficulty breathing, loss of consciousness, and meningitis. Before the vaccine was created, Hib killed 1,000 children per day worldwide. When Rachel Schneerson and John Robbins discovered they needed both a carbohydrate and a protein to generate an immune response to the Hib vaccine, they got to work.

Since the development of this life-saving vaccine, incidence of Hib has declined 99% since the prevaccine era in the United States. Thanks to Schneerson and Robbins, millions of children are safe from Hib.


As we approach International Day of Immunology on April 29th, we are highlighting heroes of immunology that have profoundly changed and saved lives throughout history and today we are honoring an immunologist whose breakthrough has led to the saving of many of our lives.

Barney Graham, deputy director of the NIH Vaccine Research Center, is the immunologist who developed the mRNA platform used as the basis to create many of the successful COVID-19 vaccines, such as those developed by Moderna and Pfizer-BioNTech. He was able to capitalize on his expertise in the development of vaccines for SARS and MERS—other recent coronavirus epidemics—as a starting basis for his COVID-19 vaccine research and experiments.

Graham, along with his collaborators, was named one of Time magazine’s 2021 Heroes of the Year for his role in the development of vaccines that have been highly effective in preventing the spread of COVID-19 and lessening the severity of infections during the pandemic.

Thanks to Graham’s ability to build on his research and his efficient collaboration with his fellow scientists, we are now more protected from the virus that so deeply affected the world.


As we approach International Day of Immunology on April 29th, we would like to highlight a pioneer of the future in vaccine research. Akiko Iwasaki is an immunologist at Yale University School of Medicine who studies how the immune system recognizes and interacts with viruses such as herpes simplex virus, influenza, and more recently coronavirus. She has made major advances in vaccine strategies to establish whole-body immunity.

Herpes simplex virus infects nerve cells and causes sores in the mouth or genital tract. Due to the nature of this virus, creating a vaccine has been difficult. However, Iwasaki pioneered a new “prime-and-pull” method, which trains immune cells and then directs them to the site of infection.

Recently, Iwasaki has turned her efforts to studying SARS-CoV2, the virus that causes COVID-19. Her lab has a foundation in studying influenza, so when the pandemic began, they had the expertise to begin SARS-CoV2 research immediately. Her team pioneered a nasal vaccine strategy to protect lungs against infection.

Iwasaki’s work has created the foundation for current and future vaccine science. Her findings today are important to combat against future diseases and pandemics.

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