How Long After Recovering From COVID-19 Does Brain Fog Usually Appear?

Reviewed by Suo Lee, MD

Internal Medicine

Brain fog from COVID-19 can start a few weeks after recovery, but the timing can vary a lot between people.

Explanation

Brain fog means having trouble thinking clearly, remembering things, or concentrating. Some studies have found that many people notice brain fog within a few weeks after they start feeling better from COVID-19. However, not everyone experiences it the same way. Some people may experience these symptoms right after recovering, while others might not notice any issues until a month or two later—or even longer. This difference can be due to many factors such as how severe the illness was, a person’s overall health, and other stress factors after infection. Research on COVID-19 survivors, including those who were in the hospital, has shown that cognitive symptoms like brain fog can appear and sometimes last for months. Because everyone’s experience is different, it is important to watch for any changes in your memory or cognitive function after COVID-19 and discuss them with a healthcare provider if they last longer than expected.

(References)

Nouraeinejad A. Brain fog as a Long-term Sequela of COVID-19. SN Compr Clin Med. 2023;5(1):9. doi: 10.1007/s42399-022-01352-5. Epub 2022 Nov 24. PMID: 36466122; PMCID: PMC9685075.
Fernández-de-Las-Peñas C, Cancela-Cilleruelo I, Rodríguez-Jiménez J, Arias-Navalón JA, Martín-Guerrero JD, Pellicer-Valero OJ, Arendt-Nielsen L, Cigarán-Méndez M. Trajectory of post-COVID brain fog, memory loss, and concentration loss in previously hospitalized COVID-19 survivors: the LONG-COVID-EXP multicenter study. Front Hum Neurosci. 2023 Nov 9;17:1259660. doi: 10.3389/fnhum.2023.1259660. PMID: 38021227; PMCID: PMC10665893.
Hayashi T, Iwata M. Spontaneous recovery from post-COVID-19 brain fog. PCN Rep. 2024 Jan 24;3(1):e169. doi: 10.1002/pcn5.169. PMID: 38868481; PMCID: PMC11114291.
sadi-Pooya AA, Akbari A, Emami A, Lotfi M, Rostamihosseinkhani M, Nemati H, Barzegar Z, Kabiri M, Zeraatpisheh Z, Farjoud-Kouhanjani M, Jafari A, Sasannia S, Ashrafi S, Nazeri M, Nasiri S, Shahisavandi M. Long COVID syndrome-associated brain fog. J Med Virol. 2022 Mar;94(3):979-984. doi: 10.1002/jmv.27404. Epub 2021 Oct 24. PMID: 34672377; PMCID: PMC8662118.

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