COVID-19

=== Long-term effects ===
{{Further|Long COVID}}

Around 10% to 30% of non-hospitalised people with COVID-19 go on to develop [[long COVID]]. For those that do need hospitalisation, the incidence of long-term effects is over 50%.<ref name="davis">{{#invoke:cite journal ||vauthors=Davis HE, McCorkell L, Vogel JM, Topol EJ |date=March 2023 |title=Long COVID: major findings, mechanisms and recommendations |journal=Nature Reviews. Microbiology |volume=21 |issue=3 |pages=133–146 |doi=10.1038/s41579-022-00846-2 |pmc=9839201 |pmid=36639608}}</ref> Long COVID is an often severe multisystem disease with a large set of symptoms. There are likely various, possibly coinciding, causes.<ref name="davis" /> Organ damage from the acute infection can explain a part of the symptoms, but long COVID is also observed in people where organ damage seems to be absent.<ref name="pmid35594336">{{#invoke:cite journal ||vauthors=Castanares-Zapatero D, Chalon P, Kohn L, Dauvrin M, Detollenaere J, Maertens de Noordhout C, Primus-de Jong C, Cleemput I, Van den Heede K |date=December 2022 |title=Pathophysiology and mechanism of long COVID: a comprehensive review |url= |journal=Annals of Medicine |volume=54 |issue=1 |pages=1473–1487 |doi=10.1080/07853890.2022.2076901 |pmc=9132392 |pmid=35594336}}</ref>

By a variety of mechanisms, the lungs are the organs most affected in COVID{{nbhyph}}19.<ref name="Torres">{{#invoke:cite journal || vauthors = Torres-Castro R, Vasconcello-Castillo L, Alsina-Restoy X, Solis-Navarro L, Burgos F, Puppo H, Vilaró J  | title = Respiratory function in patients post-infection by COVID-19: a systematic review and meta-analysis | journal = Pulmonology | date = November 2020 | volume = 27 | issue = 4 | pages = 328–337 | pmid = 33262076 | pmc = 7687368 | doi = 10.1016/j.pulmoe.2020.10.013 | publisher = Elsevier BV | s2cid = 227162748 }}</ref> In people requiring hospital admission, up to 98% of CT scans performed show lung abnormalities after 28 days of illness even if they had clinically improved.<ref>{{#invoke:cite journal || vauthors = Shaw B, Daskareh M, Gholamrezanezhad A | title = The lingering manifestations of COVID-19 during and after convalescence: update on long-term pulmonary consequences of coronavirus disease 2019 (COVID-19) | journal = La Radiologia Medica | volume = 126 | issue = 1 | pages = 40–46 | date = January 2021 | pmid = 33006087 | pmc = 7529085 | doi = 10.1007/s11547-020-01295-8 }}</ref> People with advanced age, severe disease, prolonged ICU stays, or who smoke are more likely to have long-lasting effects, including pulmonary fibrosis.<ref name="Rai">{{#invoke:cite journal || vauthors = Zhao YM, Shang YM, Song WB, Li QQ, Xie H, Xu QF, Jia JL, Li LM, Mao HL, Zhou XM, Luo H, Gao YF, Xu AG  | title = Follow-up study of the pulmonary function and related physiological characteristics of COVID-19 survivors three months after recovery | journal = eClinicalMedicine | volume = 25 | pages = 100463 | date = August 2020 | pmc = 7654356 | doi = 10.1016/j.ijtb.2020.11.003 | pmid = 32838236 }}</ref> Overall, approximately one-third of those investigated after four weeks will have findings of [[pulmonary fibrosis]] or reduced lung function as measured by [[DLCO]], even in asymptomatic people, but with the suggestion of continuing improvement with the passing of more time.<ref name="Torres" /> After severe disease, lung function can take anywhere from three months to a year or more to return to previous levels.<ref>{{#invoke:Cite news||title=COVID-19 Lung Damage |url=https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/what-coronavirus-does-to-the-lungs |publisher=Johns Hopkins Medicine |access-date=21 May 2022 |date=28 February 2022}}</ref>

The risks of [[cognitive deficit]], [[dementia]], psychotic disorders, and [[epilepsy]] or seizures persists at an increased level two years after infection.<ref>{{#invoke:cite journal ||vauthors=Taquet M, Sillett R, Zhu L, Mendel J, Camplisson I, Dercon Q, Harrison PJ  |date=August 2022 |title=Neurological and psychiatric risk trajectories after SARS-CoV-2 infection: an analysis of 2-year retrospective cohort studies including 1 284 437 patients |journal=The Lancet Psychiatry |doi=10.1016/S2215-0366(22)00260-7 |pmid=35987197 |pmc=9385200 |s2cid=251626731 |issn=2215-0366 |volume=9 |issue=10 |pages=815–827}}</ref>