"Coronaviruses cause both COVID-19 and SARS. SARS-CoV is the virus that causes SARS, whereas COVID-19 is caused by SARS-CoV-2..."

"...Both are coronavirus-caused respiratory illnesses that are transmitted by respiratory droplets produced when a person with the virus coughs or sneezes." 

"...Despite these similarities, there are also some significant distinctions between the two..."

"The SARS-CoV-2 virus disables this receptor when it binds to it to enter the cell. Researchers believe that decreased production contributes to the over-expression of the pro-inflammatory immune system response and cytokine storm driving severe cases of Covid-19..."

"In contrast to the vast majority of individuals, a few suffer from a severe condition that may lead to death. While age and underlying illnesses are the most significant risk factors, it is completely possible that other unusual mutations altering the immune response may have an influence on the death rate of young individuals. Many infectious illness susceptibilities have a strong hereditary component, and some individuals are inherently resistant to norovirus, rotavirus, and even HIV. This may as well be the case for COVID-19."

"Acute respiratory distress syndrome (ARDS) is a result of a viral pneumonia caused by the SARS coronavirus 2 (SARS-CoV-2) infection. Viral pneumonia and ARDS symptoms can coexist in their presentations, making severe COVID-19 a hybrid condition. PMID: 32572965"

The researchers also discovered that those with a predisposition to coagulation abnormalities (thrombosis, thrombocytopenia) inherited from their parents were more likely to suffer serious side effects from exposure to COVID-19. Researchers found a 2-fold increase in the risk of COVID-19 mortality due to an SNP in the factor 3 gene, which codes for a component of the coagulation cascade. 

A July 2021 meta-analysis of genetics studies on COVID-19 attempted to consolidate what is known about genetics and who gets sick. Many of the genetics studies included in the analysis point to the same variants. The new meta-analysis also shed additional light on a variant in the TYK2 gene. PMID: 32558485

This list also includes some variants identified by the UK Biobank study

Some people develop symptoms that last for a longer period of time than is typical for a seasonal respiratory virus. Around 376,000 people in the UK report symptoms more than a year after covid-19 including extreme fatigue and other symptoms similar to post-viral fatigue syndromes and ME/CFS.

This report lists genetic variants involved in immune responses that have also been found to be associated with persistent Chronic Fatigue Syndrome and/or ME, after viral infection.