Ted Cruz called Big Bird getting COVID-19 vaccine "propaganda." This isn't the first time Sesame Street encouraged kids to get important vaccines.

Big Bird – the fictional yellow bird children have watched on "Sesame Street" since the 1970s – tweeted this weekend that he received his COVID-19 vaccine. While the tweet was meant to ease any fears young children may have about getting the shot, Republican Senator Ted Cruz took a swipe at Big Bird, calling the tweet "propaganda."

"I got the COVID-19 vaccine today! My wing is feeling a little sore, but it'll give my body an extra protective boost that keeps me and others healthy," Big Bird's tweet reads.

The Texas senator retweeted it with a message: "Government propaganda…for your 5 year old!" The spat comes less than a week after the Centers for Disease Control and Prevention recommended Pfizer's pediatric vaccine for children ages 5-11 on November 2.

Campaigns to encourage people get important vaccinations are not new. In fact, in 1956, Elvis Presley encouraged young Americans to get the polio vaccine by getting his shot before the press, ahead of an appearance "The Ed Sullivan Show."

Polio had been one of the most feared diseases in the U.S. until the introduction of the first polio vaccines in 1955, the CDC says. Thanks to successful vaccination program, polio was eliminated from the United States in 1979.

Big Bird has encouraged people to get important vaccines before as well. In 1972, the character took part in a "Don't wait, vaccinate" segment, encouraging people to get the measles vaccine.

Before the measles vaccination program started in 1963, an estimated 3 to 4 million people got measles each year in the United States, the CDC says. But since then, widespread use of the measles vaccine has led to a greater than 99% reduction in measles cases compared with the pre-vaccine era. 

Big Bird's recent vaccination was part of a televised town hall with "Sesame Street," CNN and health experts, that "answered children's questions about the COVID vaccine and staying healthy, and coping with big feelings as they continue to face unprecedented challenges in their young lives." Several other characters also got "vaccinated." 

"Sesame Street" puppets are not the only high-profile figures encouraging kids, who are not immune to COVID-19, to get vaccinated. 

First lady Jill Biden and Dr. Vivek Murthy, the surgeon general, kicked off a kids vaccination campaign with a visit at a children's vaccination clinic at a Franklin Sherman Elementary School, which was also the first school in the nation to give children the polio vaccine in 1954. 

In many U.S. colleges, students are required to provide proof of COVID-19 vaccination, as the vaccine was approved for adults earlier this year. The COVID-19 vaccine is not currently required by elementary schools, but it is encouraged by health experts. 

And several other vaccines are required for kids to entire U.S. schools. 

In Texas, where Cruz is from, a minimum of seven vaccines are required for kids to attend elementary school – public or private. Like most states, Texas requires vaccines for polio, measles, hepatitis and several other diseases – sometimes before a child even turns 1. 

Dr. Scott Gottlieb, the former commissioner of the Food and Drug Administration who now serves on Pfizer's board of directors, said Sunday that he expects "broad immunity" against COVID-19 among younger children as more get vaccinated.  

"The uptake on a 5- to 11[-year-old] vaccine has been very brisk, and I suspect that uptake is going to be better than 12 to 17. There were some estimates that uptake would be less than 12 to 17. I think it could be the opposite," Gottlieb told "Face the Nation." "Right now, CVS is scheduled to deliver more than 1 million vaccines to kids ages 5 to 11 today, so I think you're going to see broad immunity get put into the child population."

Gottlieb said he doesn't think there will be mandates on COVID-19 vaccines for kids for a very long time. "I don't see that happening for years. But I do think a lot of parents are going to go out and vaccinate their children, and that's going to improve the situation of safety in schools," he said. 

CBS News has reached out to "Sesame Street" and Cruz with request for comment and is awaiting response.