To clarify, science writer @Ender5r. I talk to scientists and write (or I did) about their findings using words that the rest of us can understand but I haven’t penned anything professional in a number of years. I would refer you to the post in that I did not conflate Influenza with SARS-CoV-2 that was a leap Geit made. I think because I pointed out that we’re having such vaccine hesitancy in large part due to people like these. Of course, some people are worried that we’ve moved from live -> attenuated -> dead -> mRNA as a means of triggering an immune response. Not that mRNA vaccines are probably the future technology because of the way they work as opposed to the more traditional DNA-based ones.
Interesting that you mention poliomyelitis - a fascinating disease that had two competing vaccines: Salk’s which I think was the main one used in the USA and Sabin’s which was offered widely in Europe as I recall was attenuated and given by mouth - the same route as polio, an enterovirus, enters our bodies in the first place. A non-zero number of children went on to develop full-blown polio after receiving the Sabin vaccine. I was one of the majority of “lucky” ones. Like you I lived through measles, mumps, rubella, chickenpox and a load of others suffering from several and bearing the scars to prove it.
To quote from the Wikipedia page on Polio Vaccines:
A misconception has been present in Pakistan that polio vaccine contained haram [forbidden] ingredients and could cause impotence and infertility in male children, leading some parents not to have their children vaccinated. This belief is most common in the Kyhber province and the FATA region. Attacks on polio vaccination teams have also occurred, thereby hampering international efforts to eradicate polio in Pakistan and globally.
Younger people are so used to not suffering from these diseases they have become conduits for the sort of anti-vaxx sentiment that these idiots spread and because they are emotionally “designed by nature” to think themselves invulnerable, they are less likely to take vaccines and take more risks as a direct result. Quite a few infamous American wannbe and actual politicians have bragged about this.
While we don’t think of the flu as serious, it’s actually a very deadly virus but we’re sort of used to living with it now and many people do (incorrectly) conflate flu with the laundry list of coronaviruses and rhino viruses that cause cold symptoms. I’ve had flu twice and on both occasions it made me extremely ill with a recovery time measured in months. That was because, rather like many of the people who died in the 1918 epidemic, I was young with a highly developed immune system leading to a cytokine storm in both cases. The particular coronavirus that we’re dealing with now also causes cytokine storms but primarily in older people and the obese (something to do with lipid cells producing excess amounts of cytokines, but this isn’t really my wheelhouse so you’d have to take that with a dose of aspirin).
The last big influenza outbreak we had was Swine flu which nearly took my eldest daughter from us so please understand that I don’t underestimate flu because I’ve seen it first hand. She survived only because she’d been vaccinated but still managed to catch a fairly serious case. Bird or avian “flu” is dangerous if it makes the zoonotic leap to humans but only does so occasionally because avian viruses live at slightly higher functional temperatures than those in humans an other mammals. But if one does evolve, birds spread it like wildfire which is why it’s so dangerous.
Vitamin D is central to the functioning of a healthy immune system - which is why many countries as we move further up the globe supplement foods (milk being the main one) so that people get enough of the stuff because we’re unable to make enough from sunlight. We are, after all, a species that “walked” out of Africa which isn’t known for its short days and snowfall… 
At least you know that Vitamin D is key and not the Vitamin C fallacy - which was largely a creation of Dr. Linus Pauling (who won two Nobel prizes!) and still got that badly wrong. However our immune system is far more complex than a single vitamin as research at (IIRC, King’s College, London England) is now showing as they track Covid and look at how our gut microbiome affects our health - and not just our weight either.
All medicine is a risk-benefit balance - unless it’s homeopathic and then it’s (a) not medicine and (b) only works as a placebo so doesn’t count.
Curiously, some scientists I’ve been following have claimed to identify an anti-parastic (which I won’t name here for sake of keeping Irv’s site free of crazy conspiracy theorists). This stuff, which is naturally occurring in much the same was as penicillin, is claimed to be effective both as a preventative (prophylactic) and as a treatment for all current strains of SARS-CoV-2 and it’s out of patent, so seriously cheap. But should that be the case (I don’t know but the circumstantial evidence appears strong, despite there being no double-blind trials yet) it would make a lot of politicians look very silly and put the drug companies on a huge back foot: the losses to Moderna and Pfizer would be almost incalculable.
As for lockdowns, I just saw in the news that the Delta variant, first found in India, is now accounting for fully 83% of new cases in the UK. It’s only matter of time before that hits the continental USA in such numbers without strong interventions and serious personal responsibility! Our leaders can only do so much after all.
Stay healthy everyone and remember that Delta has already started to evade the vaccines, it’s only a matter of time before that evolves into something far worse unless we all work to stop it.
I hope that clears any misconceptions, of course, if I’ve erred, I’m happy to be corrected. I’ll have to un-sub from this because it’s a hot-button topic that will devour far too much of my time. I’m not the world’s fastest two-finger typist by any means!