From my point of view, all theories that adhere to the germ or contagion hypothesis are questionable. The paucity of literature and suppression of critical questions about this form of "science" is systematic. The deeply rooted belief that other living beings can infect us with deadly bacteria or viruses is certainly older than even the plague. If we lived under a permanently plural Enlightenment community, there would be a lot more actuation with this contagion theory and real science would never push for consensus because otherwise it is fake science. In science, as I have understood it, consensus is not really conducive, but a decision at what point you promote something into the world as true and erect a dogma on it. Every theory should be open to questioning, because that's what theories are for. That they are always looked at anew.

Apart from that, I have consciously decided to work against this kind of inculcated conviction. My decision is that it is better for me not to believe in contagion, because it makes enemies of my fellow human beings. I don't want that. Therefore, I try to find historical records that oppose this always prevailing image of "man as the enemy of man" and tell something different, a better story. If it is told by people with a sense of humour, so much the better.

I read about Salk, the eponym of the institute at the beginning of your text. He appears in connection with the machinations that the pharmaceutical industry was already engaged in at that time. I'm not surprised that today's institute continues to promote the virus theory. Even if it seems here that they are among the "good guys".
I can't find the source where I read about him. Maybe I'll give it to you later. But probably you can find it by researching about Stefan Lanka, a German biologist and critic of the vaccine narratives. If you find my suggestion worthwhile.

Here a quote from the book I previously gave you the link:

Many vaccines also cause other diseases besides the one for which they are given. For instance, smallpox vaccine often causes syphilis, paralysis, leprosy, and cancer. (See the chapters on smallpox and plagues.) Polio shots, diphtheria toxin-antitoxin, typhoid vaccine, as well as measles, tetanus and all other shots often cause various other stages of disease such as post-vaccinal encephalitis (inflammation of the brain,) paralysis, spinal meningitis, blindness, cancer (sometimes within two years,) tuberculosis, (two to twenty years after the shot,) arthritis, kidney disease, heart disease (heart failure sometimes within minutes after the shot and sometimes several hours later.) Nerve damage and many other serious conditions also follow the injections.

When several shots are given (different vaccines) within a few days or a few weeks apart, they often trigger intensified cases of all the diseases at once, because the body cannot handle such a large amount of deadly poison being injected directly into the bloodstream. The doctors call it a new disease and proceed to suppress the symptoms.

When poison is taken by the mouth, the internal defense system has a chance to quickly eject some of it by vomiting, but when the poisons are shot directly into the body, bypassing all the natural safeguards, these dangerous poisons circulate immediately throughout the entire body in a matter of seconds and keep on circulating until all the cells are poisoned.

source: http://www.whale.to/vaccine/sf.html