Study warns that coinfections with Dengue trigger the emergence of new SARS-CoV-2 variants

Medical News: The ongoing COVID-19 pandemic has seen the emergence of various variants of SARS-CoV-2, the virus responsible for the disease. A recent study from Jashore University of Science and Technology in Bangladesh sheds new light on how coinfections with dengue virus might accelerate the appearance of these variants. This Medical News report delves into the findings of the study, exploring how coinfections with dengue could be influencing the mutation rate of SARS-CoV-2 and why this might present a new challenge in controlling the virus.


Study warns that coinfections with Dengue trigger the emergence of new SARS-CoV-2 variants

The Study Background: SARS-CoV-2 Variants and Coinfections
Since the pandemic's start, the emergence of SARS-CoV-2 variants has become a significant concern for public health. Variants such as Alpha, Delta, and Omicron have displayed different transmission rates, severity, and resistance to immune responses. Until now, one of the prevailing theories has been that these variants emerge mainly from chronic infections in immunocompromised individuals. However, this study conducted in Bangladesh suggests that coinfections with other viruses, particularly dengue, could also play a role.
 
The study focused on patients diagnosed with both COVID-19 and dengue during the June-August 2021 period, aiming to explore how these coinfections might have influenced the evolution of SARS-CoV-2.
 
Key Findings: Dengue Coinfections Increase Mutation Rates
The study enrolled 572 COVID-19-positive patients in the surveillance area, of which 11 patients (2%) were also found to have dengue. Researchers performed whole-genome sequencing of SARS-CoV-2 from both coinfected and non-coinfected patients. Their findings revealed that the group with dengue coinfections exhibited significantly more mutations in the virus genome than those without. Specifically, the coinfected group showed an average of 30.6 amino acid (aa) substitutions in the SARS-CoV-2 genome, compared to 25.6 in the non-coinfected group. The difference in mutation rates between the two groups was found to be statistically significant (P < .01).
 
Additionally, the researchers identified that most of the aa substitutions in the coinfection group occurred in key regions of the virus genome, including the open reading frame (ORF) and nucleocapsid (N) proteins. These regions are essential for the virus’s replication and immune system evasion, which could explain why variants emerging from these coinfections might exhibit more significant resistance to immune responses.
 
Understanding the ARIMAX Model and Mutation Predictions
The researchers also used a complex statistical model called the ARIMAX (AutoRegressive Integrated Moving Average with Exogenous variables) model to estimate the mutation rates required for different variants to emerge. For example, they found that the Delta variant required an additional 9-12 amino acid substitutions compared to earlier variants like Alpha and Beta. Similarly, the emergence of Omicron required 19 additional aa substitutions compared to Delta.

This model allowed the team to predict how mutations accumulate over time, particularly in environments where SARS-CoV-2 is exposed to other viruses like dengue. According to the study, coinfections could force the virus to adapt faster, leading to the emergence of new variants. This increased mutation rate is likely driven by the compromised immune response in patients dealing with both infections, allowing the virus to mutate more freely and potentially become more dangerous.
 
Implications for Public Health: A New Challenge
The presence of dengue in many regions where COVID-19 is also rampant, such as Southeast Asia and parts of South America, presents a unique challenge. Dengue is endemic to many tropical regions, and the potential for SARS-CoV-2 to evolve faster in coinfected patients could mean that these areas may become hotbeds for the emergence of new variants.
 
In Bangladesh, where this study took place, dengue is a significant public health concern. The country sees seasonal outbreaks of dengue every year, and the overlap with COVID-19 outbreaks could make controlling both diseases far more difficult. The study’s findings suggest that public health officials need to consider the possibility that dengue coinfections might accelerate the emergence of new, potentially more dangerous SARS-CoV-2 variants.
 
The Role of Immune System Suppression
One of the reasons why dengue coinfections might lead to more mutations in SARS-CoV-2 is the way these viruses interact with the immune system. Dengue can cause a wide range of immune responses, including the release of various cytokines and immune cells. However, the virus also has mechanisms to evade the immune system, allowing it to persist longer in the body.
 
In patients infected with both dengue and SARS-CoV-2, the immune system is likely overwhelmed, allowing SARS-CoV-2 to replicate more freely and accumulate mutations. This weakened immune response not only prolongs the infection but also increases the chances that the virus will develop new mutations as it adapts to the host’s defenses.
 
Clinical Manifestations of Coinfection
The study found that patients with dengue and COVID-19 coinfections exhibited more severe symptoms than those with just COVID-19. These patients were more likely to experience fever, dry cough, and loss of taste and smell. Interestingly, no deaths were reported in the coinfected group, although 0.7% of the COVID-19-only patients in the study died.
 
Despite the increased mutation rates observed in the virus genome of coinfected patients, the clinical outcomes did not appear to be significantly worse, apart from the more severe symptoms. However, the study highlights the need for more research into how these mutations might influence the severity and transmissibility of the virus over time.
 
Conclusions and Future Directions
The findings of this study emphasize the importance of monitoring coinfections in regions where dengue and COVID-19 overlap. The increased mutation rates observed in SARS-CoV-2 in these coinfected patients suggest that coinfections could play a role in the ongoing evolution of the virus, potentially leading to the emergence of new variants that are more transmissible or resistant to current treatments and vaccines.
 
Moving forward, it will be crucial for researchers to continue studying the interaction between these two viruses and to expand the research into other regions where both dengue and COVID-19 are prevalent. By better understanding how coinfections drive viral evolution, public health officials can develop more effective strategies for controlling the spread of the virus and mitigating the risks associated with new variants.
 
The study findings were published in the peer-reviewed journal: Bioinformatics and Biology Insights.
https://journals.sagepub.com/doi/full/10.1177/11779322241272399
 
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