It’s hard to believe it was just over six years ago that COVID-19 altered the way we live. And while the pandemic may have been the most visible example in recent years, it certainly wasn’t the first time immunization has made a global impact. The World Health Organization (WHO) estimates that immunization has saved 154 million lives in the last 50 years, two-thirds of which were infants.

“Vaccines are among the most powerful inventions in history, making once-feared diseases preventable,” said WHO Director-General, Tedros Adhanom Ghebreyesus, Ph.D., in a news release. “Thanks to vaccines, smallpox has been eradicated, polio is on the brink, and with the more recent development of vaccines against diseases like malaria and cervical cancer, we are pushing back the frontiers of disease.”

World Immunization Week takes place April 24 through 30 this year, as a way of encouraging people of all ages to stay up to date on their vaccinations. In recognition of this week, here are three other ways vaccines have transformed the way we live.

Eradicating smallpox

Over roughly 3,000 years, some 500 million people died from smallpox, a serious virus that could cause severe scarring and blindness in those who survived. In 1796, physician Edward Jenner observed that milkmaids who had been infected with a different virus, called cowpox, seemed to be resistant to smallpox. He studied the phenomenon, transferring material from a cowpox sore to a healthy boy, who then developed immunity to smallpox. His work laid the foundation for the first vaccine. Today, smallpox is the only disease that’s ever been eradicated in humans, according to the National Foundation for Infectious Diseases.

Putting polio on the brink

In the late 19^th and early 20^th century, families around the globe were terrified of their children contracting polio, which could cause paralysis, disabilities or even death. By the 1950s, the disease killed or paralyzed more than 500,000 people a year, according to the WHO. That’s when physician Jonas Salk created the first vaccine, and after a massive vaccination campaign, cases dropped from 58,000 in 1957 to 161 in 1961. Around the world today, wild poliovirus cases have decreased by more than 99 percent, so much so that it’s been mostly eradicated, with the exception of two countries: Pakistan and Afghanistan.  

Vaccinating against cancer

More recently, the HPV vaccine has made remarkable progress towards cancer prevention. Introduced in 2006, this immunization protects people from the human papillomavirus, which is the most common sexually transmitted infection in the U.S. and is also the cause of almost all cases of cervical cancer, according to the National Cancer Institute. Researchers today say that the vaccine is nearly 100% effective at preventing persistent infections that the vaccine targets. According to Johns Hopkins Bloomberg School of Public Health, infections that cause the most cancers and genital warts have dropped 88% among teen girls and 81% among young women; and cervical precancers caused by the HPV types most linked to cervical cancer dropped by 40 percent among vaccinated people.

These examples are just a small sampling of the impact that vaccines have made—and continue to make—worldwide. You don’t have to look far to find other success stories. When was the last time you heard about a person getting sick from tetanus, mumps, rubella, pertussis and diphtheria? It’s likely that you can thank science and immunization for that. That’s why it’s important to talk to your healthcare provider about what vaccines are right for you and your family.