More than four years after the COVID-19 pandemic began, a new study sheds light on an important issue: Long COVID. Officially called post-acute sequelae of SARS-CoV-2 infection (PASC), Long COVID refers to symptoms that linger for weeks or months after the initial infection clears. These symptoms can include fatigue, trouble breathing, and cognitive issues like “brain fog.”
A recent study published in Nature Genetics aimed to uncover why some people suffer from Long COVID while others recover quickly. This research was spearheaded by the COVID-19 Host Genetics Initiative at the Germans Trias i Pujol Research Institute in Spain, and it included data from over a million participants from various global backgrounds.
According to the World Health Organization, Long COVID symptoms usually start within three months of a COVID infection and last for at least two months. Despite ongoing research, the reasons why certain individuals develop Long COVID remain largely unknown.
In their study, researchers used a method known as Genome-Wide Association Study (GWAS). This involves scanning the genome to find genetic variations that are more common in people with specific health conditions. The researchers analyzed data from over 6,450 Long COVID cases and compared it to more than one million healthy individuals.
The study identified a gene called FOXP4 that is linked to an increased risk of developing Long COVID. They discovered a specific genetic variant, rs9367106, near the FOXP4 gene. Individuals carrying the “C” version of this variant were found to be about 63% more likely to experience Long COVID symptoms than those without it. Notably, this increased risk was observed even in individuals who had mild or no symptoms during their initial COVID-19 infection.
Interestingly, the frequency of this variant varied based on population. It was found in about 1.6% of non-Finnish Europeans but up to 36% of East Asians, indicating that diverse genetic backgrounds can influence the likelihood of Long COVID.
The FOXP4 gene is particularly active in lung tissues. The study suggests that this gene might play a significant role in lung function and response to infections. Researchers found that individuals with higher levels of FOXP4 in their blood were more than twice as likely to develop Long COVID symptoms. This indicates that FOXP4 may also be linked to the immune response to respiratory infections like SARS-CoV-2.
The study underscores the importance of including diverse populations in genetic research. This is especially relevant in countries like India, which is home to a large and genetically varied population, and has been significantly affected by COVID-19.
While this study provides exciting insights into the genetic factors influencing Long COVID, researchers caution that there are limitations. Much of the data was collected before widespread vaccination, and the emergence of new COVID variants, such as Omicron, raises questions about the study’s current relevance.
Moreover, the overall genetic contribution to Long COVID appears to be modest. This means that factors such as immunity and existing health conditions may also play a crucial role.
As the world continues to deal with the effects of the COVID-19 pandemic, further research is needed, especially within diverse populations. Understanding the genetic factors involved in Long COVID could lead to better treatments and support for those suffering from this condition.
-Rashmi Kumari
