In early December 2020, a blog called Health and Money News claimed that a "head of Pfizer research" said the COVID-19 vaccine could cause female sterilization. But just how true are these claims?

The blog was shared on social media by more users, leading many people to believe that Pfizer's new COVID-19 could really lead to female sterilization.

It claimed that the COVID-19 vaccine had a spike protein that could lead to female sterilization for an "unspecified duration." It also referenced to statements made by Michael Yeadon, who did work for Pfizer but is not its research head.

(Photo : Jeenah Moon/Getty Images)
Pfizer Inc. signage is seen on July 22, 2020 in New York City.

According to Snopes, Yeadon was Pfizer's vice president and chief scientist for allergy and respiratory. He actually left the company nine years ago, according to Lockdown Sceptics.

According to statements from Yeadon and German physician Woldgang Wodarg, the Pfizer vaccine blocks a protein that is vital in the formation of placenta in females and claimed that there is a chance for women to become infertile if they are given the vaccine.

Read also: Your Questions About COVID-19 Vaccine Answered: Side Effects, Costs, and More

They sent their concerns to the European Medicines Agency and asked for clinical trials of the vaccine to be stopped in the European Union.

However, they did not say the vaccine could cause sterility, as claimed in the blog.

Pfizer COVID-19 Vaccine Allowed to be Administered in the UK

As of December 2, Pfizer has been deemed effective in the U.K. and received permission from public health officials to start administering in the region.

"Britain's Medicines and Healthcare Products Regulatory Agency recommended the vaccine after clinical trials involving tens of thousands of volunteers showed it was 95% effective and turned up no serious side effects," reported Associated Press.

Read also: CDC Calls for Universal Mask Wearing, Warns of 'High-Level Transmission' in US

But the vaccine will still be considered an experimental medication until final testing is finished.

With the emergency use approval, Britain leapt past the U.S. in the race towards a safe and effective COVID-19 vaccine.

COVID-19 Vaccine Has 'Unpleasant But Not Dangerous' Side Effects

The U.S. has two leading vaccine candidates: Moderna and Pfizer's vaccines.

Both of these consist of a snippet of genetic code involved in the production of the coronavirus spike protein through a nanoparticle, said Science Magazine.

Some believe this movement of the nanoparticle causes the body's immune response and short-term side effects.

But vaccinologist Florian Krammer said these side effects shouldn't be a cause of worry for the general public since they are mostly "unpleasant but not dangerous."

At most, people are expected to feel sore arms, fevers and fatigue due to the vaccine. "I'm not concerned about [reactogenicity]," Krammer said, adding that most people don't experience "severe' side effects that could hinder normal activity.

Snopes reached out to Pfizer for comment on the Health and Money News blog but had not yet received a response as of their publication.

The fact checking site said that there was no mention of sterility in any of Pfizer's publicly available data. A November 20 press release from the company also said there were no significant safety concerns seen during vaccine studies.

Snopes also noted that Wodard and Yeadon had been known to spread misinformation on the virus in the past, with Yeadon claiming in October that the pandemic was "effectively over" and Wodard saying in March that the seasonal flu wasn't any different from COVID-19.

But the COVID-19 pandemic is far from over. As John Hopkins School of Public Health has clarified, COVID-19 is different from the normal flu and could be a "much more serious course of illness."

There are more than a million people infected by the disease globally and over 280,000 Americans have already died from the virus.