Development, Safety, and Effectiveness

Polio is a serious disease that can cause paralysis, lifelong muscle pain and weakness, and death. Before the polio vaccine, about 16,000 cases of polio were reported each year. By 1994, polio had been eliminated in the United States because of the safe administration of approved polio vaccines.

Updated December 20, 2024 

Polio can cause serious lifelong conditions, including paralysis, muscle weakness, loss of muscle tissue, and difficulty swallowing. Even children who seem to fully recover from polio can develop severe polio symptoms later in life. The best way to prevent the serious effects of polio is to get vaccinated. All children should get four doses of IPV as part of their routine childhood vaccination schedule. Adults who are unvaccinated or incompletely vaccinated against polio should complete a three-dose series of IPV.

The polio vaccine has been part of routine childhood vaccinations for decades. Receiving the recommended doses of IPV is 99% effective at protecting children from polio and its serious effects. Routine childhood vaccination not only protects children but can also prevent the spread of polio to unvaccinated adults.

Updated December 20, 2024 

Yes. The inactivated polio vaccine (IPV) is the only polio vaccine administered as part of routine immunizations in the United States. IPV has been used since 2000 in children and adults with few adverse reactions, and it cannot cause any form of polio.   

Like all vaccines, IPV is continuously monitored by the CDC and FDA to ensure its safety and effectiveness. IPV’s safety has been consistently supported by vaccine safety monitoring systems and scientific studies. Many people receive the IPV vaccine and have no side effects. For people who experience side effects, they are usually mild. More than 250 million doses of IPV were given between 2000 and 2012, and few adverse effects were reported.

Updated December 20, 2024 

Yes. The inactivated polio vaccine (IPV) is an updated version of the polio vaccine developed by Dr. Jonas E. Salk in 1955, which helped eradicate polio in the United States. Dr. Salk’s vaccine has been enhanced a few times in the last 70 years. The latest version, IPV, has been used safely since 2000.

While there is no cure for polio, IPV is highly effective at preventing the disease. According to the CDC, two doses of IPV provide at least 90% protection, and three doses of the vaccine provide at least 99% protection.

Updated December 20, 2024 

Yes, COVID-19 vaccines have a very strong safety record. 

• Hundreds of millions of people in the United States have safely received a COVID-19 vaccine.
• COVID-19 vaccines have been tested and monitored for safety more than any previous vaccine in U.S. history.
• CDC continues to monitor and provide updates on vaccine safety via the Vaccine Adverse Event Reporting System (VAERS). Anyone can submit a report to VAERS.

Learn more about COVID-19 vaccine safety reporting.

Updated October 29, 2024 

COVID-19 vaccines were developed more quickly than most previous vaccines, but their development built upon decades of previous work.

The development process included the same rigorous safety reviews that are required for all new vaccines. Researchers were able to develop the vaccines quickly, safely, and effectively because the urgency of the pandemic created greater access to research funding, reduced bureaucratic obstacles, and encouraged unparalleled levels of government and industry cooperation.

As new variants appear, vaccine researchers will continue to update COVID-19 vaccines to provide the highest level of protection against the virus.

Updated October 29, 2024 

The risk of having a serious adverse reaction to the COVID-19 vaccine is very low—far lower than the risk of contracting COVID-19. 

Severe adverse reactions after vaccination are extremely rare but can cause long-term health issues. Rare adverse events have been identified and investigated through the Vaccine Adverse Event Reporting System (VAERS). 

Side effects of the COVID-19 vaccines vary from person to person. They are typically mild and subside in a few days. Common side effects include soreness and swelling in the injection site, nausea, chills, fatigue, headaches, muscle pain, or fever.

Updated October 29, 2024 

COVID-19 vaccination is essential for everyone ages 6 months and older, including people who have already had COVID-19. Data show that recently sick people who do not get vaccinated at least two months after their recovery are more likely to get COVID-19 again than people who get vaccinated after their recovery. This means that the COVID-19 vaccines increase protection against each COVID-19 re-infection.

Getting a COVID-19 vaccine is a safer, more reliable way to build protection than getting infected. Side effects from a COVID-19 vaccine are often mild and subside within a few days, whereas COVID-19 infection can cause severe side effects, or lead to hospitalization or death. 

Even if you recently had COVID-19 you should get an updated 2024-2025 vaccine, but can consider delaying vaccination by three months. 

Read more about the benefits of getting vaccinated against COVID-19.

Updated October 29, 2024