In the  https://en.wikipedia.org/wiki/Psychology - psychology  of  https://en.wikipedia.org/wiki/Human_behavior - human behavior , denialism is a person's choice to  https://en.wikipedia.org/wiki/Denial - deny  reality as a way to avoid believing in a psychologically uncomfortable truth. ^{https://en.wikipedia.org/wiki/Denialism#cite_note-FOOTNOTEMaslin2009-1 - [1]}  Denialism is an essentially  https://en.wikipedia.org/wiki/Irrational - irrational  action that withholds the validation of a historical experience or event when a person refuses to accept an  https://en.wikipedia.org/wiki/Empirical - empirically  verifiable reality. ^{https://en.wikipedia.org/wiki/Denialism#cite_note-FOOTNOTEOShea200820-2 - [2]}

In the sciences, denialism is the rejection of basic facts and concepts that are undisputed, well-supported parts of the  https://en.wikipedia.org/wiki/Scientific_consensus - scientific consensus  on a subject, in favor of ideas that are radical, controversial, or fabricated. ^{https://en.wikipedia.org/wiki/Denialism#cite_note-FOOTNOTEScudellari2010-3 - [3]}

 The terms  https://en.wikipedia.org/wiki/Holocaust_denial - Holocaust denial  and  https://en.wikipedia.org/wiki/AIDS_denialism - AIDS denialism  describe the denial of the facts and the reality of the subject matters, ^{https://en.wikipedia.org/wiki/Denialism#cite_note-4 - [4]}  and the term  https://en.wikipedia.org/wiki/Climate_change_denial - climate change denial  describes denial of the  https://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change - scientific consensus  that the  https://en.wikipedia.org/wiki/Climate_change - climate change  of planet Earth is a real and occurring event primarily caused in geologically recent times by human activity. ^{https://en.wikipedia.org/wiki/Denialism#cite_note-5 - [5]}  

The forms of denialism present the common feature of the person rejecting overwhelming evidence and trying to generate political controversy in attempts to deny the existence of consensus. ^{https://en.wikipedia.org/wiki/Denialism#cite_note-diethelm-6 - [6] https://en.wikipedia.org/wiki/Denialism#cite_note-mckee-7 - [7]}

The motivations and causes of denialism include religion, self-interest (economic, political, or financial), and  https://en.wikipedia.org/wiki/Defence_mechanism - defence mechanisms  meant to protect the psyche of the denialist against mentally disturbing facts and ideas; such disturbance is called  https://en.wikipedia.org/wiki/Cognitive_dissonance - cognitive dissonance  in psychology terms. ^{https://en.wikipedia.org/wiki/Denialism#cite_note-FOOTNOTEHambling2009-8 - [8] https://en.wikipedia.org/wiki/Denialism#cite_note-FOOTNOTEMonbiot2006-9 - [9]}

Long covid really shouldn’t have been a surprise, says Vett Lloyd, a biologist at Mount Allison University in Sackville, Canada. “When the pandemic started, the general assumption was that there were two possible outcomes to an infection—you’d either get better or die,” she says.

But there’s a possible third outcome. It’s long been known that a number of disease causing pathogens—some viral and some bacterial—are associated with ongoing post-infection symptoms in a significant minority of patients.

“There was no real reason to think SARS-CoV-2 should be any different than the original SARS, which also caused post-infection syndromes,” says Lloyd. She is one of many researchers who hope that the attention and funding directed towards long covid will help to shed light on how and why other infections can lead to persistent and sometimes debilitating symptoms.