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Vaccine testing falsely equated with thalidomide development decades ago

December 4, 2020 GMT

CLAIM: “Rapid 8 month tested vaccine? Thalidomide was a RAPID APPROVED drug introduced in 1957, to address nausea and insomnia in pregnant women. It was marketed in 50 countries before being withdrawn in 1962 due to malformations in newborns. Be careful with what is coming.”

AP’S ASSESSMENT: Missing context. There are different approval processes for the coronavirus vaccines and the drug thalidomide. Thalidomide was not approved for sale in the U.S. when first introduced in the 1950s. The drug did not undergo extensive trials as is being done with COVID-19 vaccines currently being developed. 


THE FACTS: As drugmakers seek emergency use authorization for their COVID-19 vaccines, social media users are  attempting to cast doubt about their safety because of how quickly they are being produced. 

Pfizer and Moderna recently announced that clinical trials showed their vaccines were more than 90 percent effective. When the coronavirus was declared a global pandemic in March, medical professionals predicted that developing a vaccine to combat COVID-19 could take 18 months or more.

Posts online are comparing the short time period in which COVID-19 vaccines have been developed with issues around thalidomide, a drug that was once banned worldwide for causing birth defects in babies. The drug was in development for about four years from about 1953 to 1957 before it was introduced into the German market and sold in nearly 50 countries. It was advertised as a safe, over-the-counter sedative.

The drug was not approved in the U.S. at the time, but Americans were given the drug in two clinical trials. After it was discovered that the drug led pregnant women to give birth to babies with severe birth defects, U.S. agencies changed their policy on approving drugs.

Social media users began sharing the hashtag #Thalidomide on Twitter on Wednesday after news that Britain had approved a COVID-19 vaccine made byPfizer Inc. and Germany’s BioNTech. 

“Lets hope there is going to be a full cycle testing!” one Facebook caption said in a post comparing the drug to the COVID-19 vaccine. 


Dr. S. Vincent Rajkumar, a professor of medicine at the Mayo Clinic in Rochester, Minnesota, who has studied thalidomide and use of the drug to treat myeloma, said you cannot compare the coronavirus vaccine and thalidomide. 

“One was trying to solve the problem of sleeplessness and was marketed with zero data, no efficacy or safety or randomized trials,” he said of thalidomide. “The other is trying to solve the problem of a life-threatening pandemic that has killed hundreds of thousands of people and there are two randomized trials showing the vaccines are highly effective.”

“The fact that people were efficient and fast does not mean that any of the safety steps were skipped,” Rajkumar said. 

Unlike the early trials of thalidomide in the 1960s, the coronavirus vaccines from Pfizer and Moderna have undergone several trial phases including animal and human tests. The vaccines have been tested in more than 60,000 humans and both companies showed more than 90 percent effectiveness. Trial patients reported mild side effects like muscle aches and sore arms. 

Dr. Frances Oldham Kelsey, an FDA officer in the early 1960s, found that there was not enough safety data on thalidomide as U.S. clinical trials were still being conducted and helped prevent it from being approved for use in the U.S. During the 1950s,clinical trials could be conducted without FDA approval. 

Around the world, thousands of pregnant women who had taken the drug delivered infants without limbs or flipper-like arms and legs. Some women in the U.S. got a hold of the drug from overseas or from clinical trials.  

The drug was withdrawn in the United Kingdom around Dec. 2 1961. 

Due to the work highlighted by Kelsey, President John F. Kennedy signed the Kefauver-Harris Drug Amendments to the Federal Food, Drug and Cosmetics Act, which changed drug oversight in the U.S., requiring manufacturers to prove drugs were both safe and effective. The law also required testing on humans. 

Thalidomide was approved by the FDA in 1997 under tight restrictions to treat inflammation in leprosy patients. It has since been approved for other uses although it is not approved for use by pregnant women. 

Later this month, the FDA will consider authorizing emergency use of two vaccines made by Pfizer and Moderna. Current estimates project that no more than 20 million doses of each vaccine will be available by the end of 2020. And each product requires two doses. As a result, the shots will be rationed in the early stages. 


This is part of The Associated Press’ ongoing effort to fact-check misinformation that is shared widely online, including work with Facebook to identify and reduce the circulation of false stories on the platform.

Here’s more information on Facebook’s fact-checking program: