COVID-19 pandemic

=== Transmission ===

{{Main|Transmission of COVID-19}}
The disease is mainly transmitted via the respiratory route when people inhale droplets and small airborne particles (that form an [[aerosol]]) that infected people exhale as they breathe, talk, cough, sneeze, or sing.<ref name="Wang_2021">{{#invoke:cite journal || vauthors = Wang CC, Prather KA, Sznitman J, Jimenez JL, Lakdawala SS, Tufekci Z, Marr LC | title = Airborne transmission of respiratory viruses | journal = Science | volume = 373 | issue = 6558 | date = August 2021 | pmid = 34446582 | pmc = 8721651 | doi = 10.1126/science.abd9149 | bibcode = | doi-access = free }}</ref><ref name="auto">{{#invoke:cite journal || vauthors = Greenhalgh T, Jimenez JL, Prather KA, Tufekci Z, Fisman D, Schooley R | title = Ten scientific reasons in support of airborne transmission of SARS-CoV-2 | journal = Lancet | volume = 397 | issue = 10285 | pages = 1603–1605 | date = May 2021 | pmid = 33865497 | pmc = 8049599 | doi = 10.1016/s0140-6736(21)00869-2 }}</ref><ref name="AR2021">{{#invoke:cite journal || vauthors = Bourouiba L | title = Fluid Dynamics of Respiratory Infectious Diseases | journal = Annual Review of Biomedical Engineering | volume = 23 | issue = 1 | pages = 547–577 | date = July 2021 | pmid = 34255991 | doi = 10.1146/annurev-bioeng-111820-025044 | hdl-access = free | s2cid = 235823756 | hdl = 1721.1/131115 }}</ref><ref name="auto1">{{#invoke:cite journal || vauthors = Stadnytskyi V, Bax CE, Bax A, Anfinrud P | title = The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 117 | issue = 22 | pages = 11875–11877 | date = June 2020 | pmid = 32404416 | pmc = 7275719 | doi = 10.1073/pnas.2006874117 | bibcode = 2020PNAS..11711875S | doi-access = free }}</ref> Infected people are more likely to transmit COVID-19 when they are physically close to other non-infected individuals. However, infection can occur over longer distances, particularly indoors.<ref name="Wang_2021" /><ref name="Miller_2021">{{#invoke:cite journal || vauthors = Miller SL, Nazaroff WW, Jimenez JL, Boerstra A, Buonanno G, Dancer SJ, Kurnitski J, Marr LC, Morawska L, Noakes C | title = Transmission of SARS-CoV-2 by inhalation of respiratory aerosol in the Skagit Valley Chorale superspreading event | journal = Indoor Air | volume = 31 | issue = 2 | pages = 314–323 | date = March 2021 | pmid = 32979298 | pmc = 7537089 | doi = 10.1111/ina.12751 }}</ref>