**2. Sequels due to COVID-19, post-COVID-19 condition, or long COVID-19**

Most patients with COVID-19 recover after acute infection with SARS-CoV-2, but some report persistent complications. Michelin et al. [15] conclude that the studies up to 2021 were quite heterogeneous and mostly from Western European countries, with little representation from low to mid-developed countries.

The definition of this disease has changed throughout the pandemic, emerging with various names, including long-term COVID or post-COVID-19 condition [15].

Syndromes due to post-acute infection have previously been reported [16]. According to the review by Choutka et al. [16], the possible causes of these syndromes are remnants or reservoirs of the pathogen that caused the primary infection, autoimmune response, dysbiosis or reactivation, and tissue damage.

In the case of COVID-19, the active SARS-CoV-2 virus has been found even 3 to 6 months after infection [17]. For their part, Wallukat et al. [18] explore the relationship between prolonged COVID and the autoimmune response, finding autoantibodies in most patients who developed long COVID-19. Regarding the last two possible causes of long COVID, gastrointestinal affectations have been reported, in addition to the damage to lung tissues [3].

Prolonged COVID-19 can generate limitations in the daily activities of patients. The situations where a person with long COVID-19 is affected in their daily activities are diverse, for example:

Those with lung damage will have shortness of breath, fatigue, and these effects are mainly related to a limitation in respiratory function [19]. Those presenting with symptoms such as intestinal pain and nausea that have persisted for months are associated with limited gastrointestinal function [19].

People who experience memory problems or "brain fog" suffer from issues related to concentration or thinking [19].

The long-term sequelae generated by COVID-19 are unknown. However, repercussions have been reported worldwide at various systemic levels. These include pulmonary, cardiovascular, neurological, and even mental health. Although these conditions are not lethal, they damage the quality of life. In the case of the Mexican population, these sequelae are associated with the comorbidities that occur most frequently in this population. Long-term complications secondary to COVID-19 could be expected later [20].

The following sections report the most common complications reported in the literature.
