Twin studies show strong genetic effects on COVID-19

As of October 7, 2021, Coronavirus Disease 2019 (COVID-19) has killed more than 4.82 million people worldwide. Much research is being encouraged by the need to identify factors associated with the spread and pathogenicity of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19.

New survey published on preprint server medRxiv * Data from twin studies will be used to discuss the strong multifactorial causal potential of SARS-CoV-2 infection.

study: “Twin COVID-19: What can we learn from them?” Image Credit: Marian Weyo / Shutterstock.com

Background

After the emergence of SARS-CoV-2 in Wuhan, China at the end of 2019, several vaccines aimed at ending the SARS-CoV-2 community infection by raising the level of SARS-CoV-2 have been released. It was developed rapidly. Herd immunity..vaccination Effectiveness Since then, we have challenged the emergence of new SARS-CoV-2 mutants that are more contagious and sometimes more toxic than their ancestral strains.

In addition, some SARS-CoV-2 variants can avoid neutralization by antibodies induced by previous exposure to ancestral viral antigens, either by natural infection or vaccination. Such strains are called Variant of Concern (VOC).

Early studies of the etiology and severity of COVID-19, like other infectious agents, showed infection rate, severity, and adverse effects in pairs of identical twins (MZ) and fraternal twins (DZ). Includes a comparison of outcomes. The purpose is to detect any genetic factors that contribute to susceptibility.

If susceptibility is primarily determined by environmental factors, the overall risk of illness or infection in a pair of twins is equal. Conversely, the presence of genetic components has a higher degree of similarity in results between MZ twins with the same genetic code compared to DZ twins with only a degree of shared genetic programming siblings. Indicated by gender.

The current group of researchers has previously shown that the clinical features of post-infection disease deca congenital syndrome (ZCS) in members of a pair of twins showed inconsistencies according to the genetic makeup of twin babies. .. This was despite the fact that both were exposed to the virus during pregnancy.

In the case of COVID-19, such direct comparisons are difficult because, in addition to extreme fluctuations in clinical symptoms, members of the twin pair may not be equally exposed. Some infected people are completely asymptomatic, while others, regardless of age, develop severe illness or succumb to the illness.

From the early stages, COVID-19 has been reported to cause illness and death in identical twins, both dying within days or hours of each other. It began with a set of adult MZ twins who died every three days in April 2020. This raises questions about the involvement of genetic factors in the disease. Continuously.

The current treatise describes the COVID-19 results in 10 twin pairs, half of which were MZ and half of which were DZ twins. All the twins included in the current study came from the city of São Paulo, Brazil.

Investigation result

Of the twin pairs, at least one of each pair was tested positive for COVID-19. Both twins shared a bedroom and used no means to protect themselves from the virus at home. In most cases, infected twins were infected by one or more relatives.

Researchers found that four out of five pairs of MZ twins showed a consensus of infection. That is, both twins were either symptomatic or asymptomatic. However, the opposite was true for the five DZ twin pairs, four of which showed discrepancies.

In a single pair of MZ twins that did not show a match, both were infected and exhibited Symptoms of COVID-19.. However, one re-infected and developed a serious illness, and the other had only one episode of infection with mild symptoms.

This supports the findings of previous reports of adult MZ twin pairs with inconsistent clinical manifestations.

In one case, the twins had multiple common medical conditions, including type 2 diabetes, high blood pressure, and higher body mass index (BMI) values. Surprisingly, the twins with more medical complications had milder and shorter episodes, while the other was hospitalized with serious COVID-19.

In another, the individual was healthy, but one developed severe COVID-19 requiring mechanical ventilation and the other rapidly recovered from a mild seizure. This is true even for congenital infections with pathogens such as the human immunodeficiency virus (HIV) and cytomegalovirus, exposing MZ twins to the same virus. In utero Nevertheless, it develops a variety of clinical illnesses.

Meanwhile, Brazilian media reports on seven or more identical twin pairs who died within days or weeks of each other. Of these, 6 are male, consistent with a known increased risk of severe COVID-19 in this gender. But these twins weren’t together, and there was no underlying illness. This indicates that genetic factors play a major role in the consistent clinical course.

Conclusion

“”In conclusion, these observations derive from a small sample, but complex multifactorial inheritance that regulates susceptibility or resistance to SARS-CoV-2 infection by the disagreement rate between DZ twins and the higher concordance of MZ. Is further supported... “

*Important Notices

medRxiv Publish preliminary scientific reports that should not be considered definitive as they are not peer-reviewed, guide clinical practice / health-related behaviors, and should not be treated as established information.