Chronic Antihistamine Use Linked to Lower Risk of COVID-19 Severity and COVID-19 Mortality

Medical News: In an unexpected development from a recent study, researchers have discovered that chronic use of antihistamines could significantly lower the risk of severe COVID-19 outcomes. This finding emerged from a detailed analysis conducted in Spain, where COVID-19 cases and hospitalization rates were examined closely among individuals with chronic medical prescriptions. Patients on antihistamines were found to have reduced hospital admission and mortality rates when compared to those who were not taking such medications.


Chronic Antihistamine Use Linked to Lower Risk of COVID-19 Severity and COVID-19 Mortality

The study was conducted by a team of researchers from multiple prestigious institutions, including the Consorci Sanitari de Terrassa (CST), the University of Barcelona, and the Hospital Álvaro Cunqueiro in Vigo. This Medical News report explores their findings and sheds light on the possible connection between antihistamine use and improved COVID-19 outcomes.
 
Background of the Study
COVID-19, which began as an isolated outbreak in late 2019, quickly turned into a global health emergency. Spain, one of the hardest-hit countries during the first wave, reported alarming mortality rates, especially among older adults and residents of nursing homes. Early studies suggested that certain medications, including antihistamines and azithromycin, might have played a role in reducing severe outcomes.
 
This study focused on a more recent investigation into chronic antihistamine use and its impact on COVID-19 patients. The researchers analyzed data from a large healthcare population in Spain, covering over 140,000 individuals. The study examined infection rates, hospitalization trends, and mortality among patients with chronic conditions who were or were not prescribed antihistamines.
 
What the Researchers Discovered
The study’s key findings revealed a notable difference in COVID-19 outcomes between patients with chronic antihistamine prescriptions and those without. The most significant results included:
 
-Lower Hospital Admissions: Patients taking antihistamines regularly were far less likely to require hospitalization due to COVID-19. For example, in groups receiving 2 to 7 other chronic treatments, the odds of being hospitalized were significantly reduced by about 50%.
 
-Reduced Mortality Rates: Remarkably, the study found that no deaths occurred in patients on antihistamines with up to six other prescribed treatments. This trend persisted across all age groups, including vulnerable elderly populations.
 
-Impact of Vaccination: While vaccination status improved outcomes overall, the benefits of antihistamines were evident even among unvaccinated patients. For non-vaccinated individuals on antihistamines, the reduction in hospital admissions and deaths was particularly pronounced.
 
To put it in perspective, among patients not on antihistamines, the odds of hospital admission were approximately double compared to those who were. Similarly, death rates in unvaccinated patients were far higher in those without antihistamine prescriptions.
 
Understanding the Role of Antihistamines
Antihistamines are commonly used to treat allergic conditions like hay fever, skin rashes, and asthma. They work by blocking histamine, a chemical in the body that triggers allergy symptoms. However, in recent years, researchers have started exploring other benefits of antihistamines, particularly in viral infections.
 
In the case of COVID-19, it is believed that antihistamines might help in several ways:
 
-Immune Modulation: Histamines can influence the immune system and contribute to the severe inflammatory response, known as the “cytokine storm,” seen in severe COVID-19 cases. By blocking histamines, antihistamines may reduce inflammation and prevent complications.
 
-Antiviral Effects: Some antihistamines have shown antiviral activity against other viruses in lab studies. This effect could help reduce the severity of COVID-19 infections.
 
-Improved Respiratory Health: Since antihistamines help alleviate symptoms like nasal congestion and breathing difficulties, they may indirectly support patients during mild or moderate COVID-19 infections.
 
The findings of this study align with previous research conducted in nursing homes, where residents receiving antihistamines and azithromycin during the pandemic’s early waves experienced no hospitalizations or deaths.
 
Study Design and Methods
The study was conducted in a healthcare population served by the Consorci Sanitari de Terrassa (CST) in Barcelona. Researchers analyzed data collected over three years, from March 2020 to May 2023. They categorized patients based on the number of chronic treatments they were receiving, their vaccination status, and whether they had antihistamine prescriptions.
 
Patients were divided into groups:
-No Chronic Treatments (0 nT)
-1 Chronic Treatment
-2 to 7 Chronic Treatments
-8 or More Chronic Treatments
 
The research team then compared COVID-19 infection rates, hospital admissions, and mortality between patients with and without antihistamines. Statistical analysis revealed significant differences, especially in hospitalized cases.
 
What This Means for the Future
The study provides compelling evidence for the potential protective role of antihistamines in COVID-19 management. While more clinical trials are needed to confirm these effects, the findings suggest several practical implications:
 
-Reevaluating Antihistamines in COVID-19 Treatment: Chronic antihistamine use could serve as a low-cost, widely available intervention to reduce severe COVID-19 outcomes, especially in high-risk populations.
 
-Focus on Early Treatment: The results support the idea that antihistamines might be effective when administered early in the course of COVID-19. This could prevent hospitalizations and improve overall recovery.
 
-Further Research: Randomized clinical trials are necessary to confirm these findings and explore specific antihistamines that provide the most benefit. Drugs like cetirizine, loratadine, and famotidine have already shown promise in previous studies.
 
Final Conclusions
In summary, the study found that chronic antihistamine prescriptions were linked to reduced hospital admissions and deaths in COVID-19 patients. These benefits were observed across different age groups, vaccination statuses, and levels of chronic illness severity. Importantly, no deaths were reported in patients taking antihistamines alongside up to six other chronic treatments, highlighting their potential role in protecting against severe outcomes.
 
This research underscores the safety of antihistamines and suggests they could play a critical role in managing COVID-19, especially among vulnerable populations. The findings align with previous observations in nursing homes and primary care settings, where antihistamine use correlated with better clinical outcomes. Moving forward, randomized trials will be essential to validate these results and determine the most effective antihistamine therapies for COVID-19.
 
The study findings were published in the peer-reviewed journal: Microorganisms.
https://www.mdpi.com/2076-2607/12/12/2589
 
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