A conservative radio host in Tennessee who urged listeners not to get vaccinated against Covid-19 has changed track and called on listeners to get the shot, after contracting the virus and ending up in hospital in “very serious condition”.

In a statement posted to social media, Phil Valentine’s family detailed his condition and said: “Please continue to pray for his recovery and PLEASE GO GET VACCINATED!”

The family also said the WTN host had “never been an ‘anti-vaxer’”, but “regrets not being more vehemently ‘pro-vaccine’ and looks forward to being able to more vigorously advocate that position as soon as he is back on the air, which we all hope will be soon”.

Valentine, 61, did, however, play down the need for vaccines and perform a song called Vaxman, to the tune of Taxman, George Harrison’s Beatles number against government taxation.

“Let me tell you how it will be,” he sang, “and I don’t care if you agree, ‘Cause I’m the Vaxman, yeah I’m the Vaxman. If you don’t like me coming round, be thankful I don’t hold you down.”

As the Delta variant of the coronavirus fuels steep rises in cases across the US, rural and mostly Republican-run states trail in vaccination numbers and have emerged as hotspots for infection, straining health resources.

Republican politicians and influential rightwing broadcasters including Fox News hosts have begun to call for people to get the shot.

Tennessee is trailed only by deep-south states in vaccination rates and has seen political wrangles over access to vaccination for teenagers and in one instance an attack by a woman who shouted “No vaccine” as she allegedly attempted to mow down health workers with her car.

On Saturday, data shared with the Guardian showed that authorities in Memphis believe 80% of new Covid cases in the city involve the Delta variant.

One nurse at the Methodist University hospital said: “Seeing patient after patient go through this, especially at the point where we actually have something that has proven efficacy … It’s just sad to see it, that we’re back at this point.”

In December, Valentine wrote on his blog that though former president Donald Trump should get more credit for supporting the swift development of Covid-19 vaccines, “the vaccine isn’t for everyone”.

He added: “If I decide not to get vaccinated, I’m not putting anyone else’s life in danger except perhaps people who have made the same decision. With this thing being 95% effective, there’s really no way I’m going to infect someone who’s had the shot. That’s if I even get the virus.”

Breakthrough infections are possible. Health authorities say those who have had Covid-19 should still get the vaccination.

Valentine also wrote that he was “not an anti-vaxxer. I’m just using common sense. What are my odds of getting Covid? They’re pretty low. What are my odds of dying from Covid if I do get it? Probably way less than 1%. I’m doing what everyone should do and that’s my own personal health risk assessment.

“If you have underlying health issues you probably need to get the vaccine. If you’re not at high risk of dying from Covid then you’re probably safer not getting it. That evokes shrieks of horror from many, but it’s true. I’m weighing the known versus the unknown.”

CNN reported that Valentine also “tried to draw comparisons between hospital workers who had to indicate their Covid-19 vaccination status on their work ID badges with Jews forced to wear yellow stars in Nazi Germany”.

Harsh rhetoric against proof of vaccination or other public health measures has spread. Marjorie Taylor Greene, a far-right congresswoman from Georgia, was recently forced to apologise for comparing mask mandates to measures implemented by the Nazis.

On Thursday, Valentine’s family said he was “suffering from Covid pneumonia and the attendant side effects. He is in the hospital in the critical care unit breathing with assistance but is NOT on a ventilator.”

They added: “Phil and his family would like for all of you to know that he loves ya’ll and appreciates your concern, thoughts and prayers more than you will ever know.”