Latest news with #HSV1
Daily Mail
3 days ago
- Health
- Daily Mail
How dementia could be triggered by cold sore virus: Cutting-edge research shows it can inflame your brain. But doctors say there's a free NHS jab that can slash your risk - and reveal what to ask for
Could something as simple as getting a shingles jab significantly reduce your risk of dementia? That's the intriguing possibility raised by a growing body of scientific research, which points to common viruses as the true cause. Just last week researchers reported that people who'd had antivirals to treat another herpes virus, herpes simplex virus type 1 (HSV-1) which causes cold sores, had a lower risk of developing Alzheimer's disease.
Fox News
6 days ago
- Health
- Fox News
Cold sores may play role in Alzheimer's development, new research reveals
Cold sores may play a role in the development of Alzheimer's disease, according to a new study published in BMJ Open. Researchers examined 344,628 "case-control pairs." The pairs were matched in age, sex, geographical region and number of healthcare visits — but one had Alzheimer's disease and one did not. Of the groups studied, 1,507 people with Alzheimer's also had herpes simplex virus type 1 (HSV-1), which is the most common cause of cold sores. Only 823 people in the control group had HSV-1. Among these 2,330 people, 40% used anti-herpetic medication following their diagnosis. Those who were treated for the virus were 17% less likely to develop Alzheimer's disease than those who didn't use the treatments, the study found. The risk of developing this form of dementia is known to rise with age. However, the chance of an HSV-1 diagnosis was 80% higher in those diagnosed with Alzheimer's, according to the research. Less commonly, cold sores can be caused by herpes simplex virus type 2 (HSV-2). The analysis places "an even greater emphasis on viewing the prevention of herpes viruses as a public health priority," the researchers said in a press release. Overall, women made up 65% of the Alzheimer's cases. Their average age was 73, and they tended to have more co-existing conditions, which were all risk factors. The study also observed the potential role of other herpes viruses, some of which were associated with an elevated risk of Alzheimer's disease. The specific connection between viruses like HSV-1 and heightened dementia risk isn't clear, the researchers noted. "However, studies have shown that inflammatory alterations in the brain caused by HSV infection are pivotal in [Alzheimer's disease] development," they said in the release. Treatment with anti-viral therapy seems to lower the risk of Alzheimer's, "suggesting that HSV-1 treatment may be protective," the study says. "There's no cure for cold sores, but treatment can help manage outbreaks," according to Mayo Clinic. "Prescription antiviral medicine or creams can help sores heal more quickly. And they may make future outbreaks happen less often and be shorter and less serious." There were some limitations in the study, the researchers acknowledged. "Due to limited data history, HSV-1 infections prior to the patient's database entry were not included in the analysis, and it is possible that some overlap exists between HSV-1 and HSV-2 diagnoses," the researchers noted. "Additionally, many individuals with HSV-1 infection are asymptomatic, and others may not seek medical care during recurrences and are therefore not clinically diagnosed and recorded in the database." While an estimated two-thirds of people under 50 are infected with HSV-1, data on symptomatic infections is limited, "as manifestations can be mild or unnoticed," the researchers added. For more Health articles, visit Under-diagnosis of Alzheimer's disease could also skew the results. Fox News Digital reached out to the researchers and other doctors for comment.
Medscape
6 days ago
- Health
- Medscape
Cold Sore Virus Implicated in Alzheimer's Disease
Herpes simplex virus 1 (HSV-1) infection is associated with an increased risk of developing Alzheimer's disease (AD), but treating the viral infection may offer protection, a new study found. In a matched case-control study of nearly 700,000 older adults, HSV-1 was more common in those with AD, and antiviral therapy for HSV-1 was associated with a lower risk of developing AD. However, the authors and outside experts cautioned that no firm conclusions can be drawn from this observational study and called for more research. The study was published online on May 20 in BMJ Open . It was funded by Gilead Sciences, which is actively involved in the research and development of treatments for HSV. Mixed Data HSV-1, a common virus that causes cold sores, affects more than two thirds of the global population younger than 50 years. An association between HSV-1 and AD has been reported previously, albeit with conflicting results across various studies. One recent Taiwanese cohort study found that symptomatic HSV infection was associated with a threefold increased risk of developing dementia. Antiherpetic medication reduced the risk by 90%. However, a study of US veterans failed to link HSV infection with an increased risk for dementia. Although, like the Taiwanese findings, antiherpetic medication was associated with a protective effect against dementia. To investigate further, researchers led by Yunhao Liu, PhD, data scientist with Gilead Sciences, used the IQVIA PharMetrics Plus claims database to match 344,628 people with AD to an equal number of control individuals without AD. Compared with 823 (0.24%) control individuals without an AD diagnosis, 1507 (0.44%) individuals diagnosed with AD had a history of HSV-1. Among those with AD, nearly two thirds were women (65%), their mean age was 73 years, and they tended to have more coexisting conditions. After adjusting for relevant confounding factors, the likelihood of an HSV-1 diagnosis was 80% higher in those with AD (adjusted odds ratio [aOR], 1.80; 95% CI, 1.65-1.96). In a stratified analysis, the association of HSV-1 with AD was more pronounced in older age groups — with an aOR of 2.10 in those aged 75 years or older vs an aOR of 1.14 in those aged 50-70 years. 'These findings are consistent with studies suggesting that the neurodegenerative impact of HSV-1 becomes more apparent with age and cumulative exposures,' the authors noted. Among the 2330 adults with a history of HSV-1, 931 (40%) were treated with antiherpetic medication, which was associated with a 17% reduced risk for AD compared with no treatment (adjusted hazard ratio [aHR], 0.83; 95% CI, 0.74-0.92). 'While the molecular mechanisms remain to be fully elucidated, these results are indicative of a possible role for antiherpetic therapy in mitigating dementia risk,' the authors wrote. Caveats and Cautionary Notes F. Perry Wilson, MD, Yale School of Medicine, New Haven, Connecticut, and Medscape's Impact Factor commentator, noted in a recent commentary that studies that use administrative data have limitations and said the author's suggestion that antiherpetic therapies are potentially protective for AD-related dementia 'feels like a bit of a leap to me at this point.' On the other hand, Wilson said, 'for those who suffer from cold sores, a study like this may push you a bit toward treatment, at least during an outbreak. Short-term valacyclovir is relatively safe and reduces the duration of the cold sore by about a day, which is nice. But if it reduces your risk of dementia as well, well, it might be a no-brainer.' Several outside experts also weighed in on the study in a statement from the UK nonprofit Science Media Centre. Sheona Scales, PhD, director of research at Alzheimer's Research UK, Cambridge, England, cautioned that 'despite the large sample size, this research has limitations partly due to only using health records and administrative claims data.' 'Most people infected with HSV-1 don't have any symptoms, so some infections might not have been recorded. Infections predating the information recorded are also not available. Although cases were matched with controls, diagnosing Alzheimer's disease, especially in the early stages, remains a challenge,' Scales commented. While the study found that some people receiving medicines to treat HSV-1 infections had a lower risk for AD, 'a lot more work is needed to unpick this,' she added. 'We know there are 14 established risk factors for dementia, and there's not enough evidence to include infections in this list. This study doesn't tell us if infections are causing the risk, it only shows an association. Further research is needed to understand what the underlying biology around this is,' Scales said. Tara Spires-Jones, PhD, director of the Centre for Discovery Brain Sciences at The University of Edinburgh, Edinburgh, Scotland, said the study adds to a growing body of data linking HSV-1 and other viral infections to the risk for AD. However, 'it is important to note that HSV-1 infection, which is extremely common in the population, is by no means a guarantee that someone will develop Alzheimer's,' Spires-Jones noted. 'Why viral infections may increase risk of dementia is not fully understood, but the most likely explanation is that infections increase inflammation in the body and contribute to age-related brain inflammation. More research is needed to understand the best way to protect our brains from Alzheimer's disease as we age, including a better understanding of links between viral infection and Alzheimer's risk,' Spires-Jones said. Richard Oakley, PhD, director of Research and Innovation at Alzheimer's Society, London, England, cautioned that the study 'doesn't prove that cold sores cause Alzheimer's disease, or that antivirals prevent it. Much more research is needed to explore exactly how viruses might be involved and before we can draw firm conclusions.'
The Independent
7 days ago
- Health
- The Independent
Scientists discover surprising link between common virus and dementia
Research suggests a link between herpes simplex virus type 1 (HSV-1), commonly associated with cold sores, and an increased risk of Alzheimer's disease. A large-scale US study found that individuals with a history of HSV-1 infection had an 80 per cent higher risk of developing Alzheimer's. The study also indicated that using antiviral medications to treat HSV-1 could potentially lower the risk of Alzheimer's by 17 per cent. While the exact mechanism linking HSV-1 and Alzheimer's remains unclear, researchers suspect inflammation caused by the virus may play a role. Further research is needed to confirm these findings and determine the most effective strategies for preventing Alzheimer's, including the potential role of antiviral therapies, the researchers said.
Medscape
20-05-2025
- Health
- Medscape
The Strange Link Between Cold Sores and Alzheimer's Disease
This transcript has been edited for clarity. Welcome to Impact Factor , your weekly dose of commentary on a new medical study. I'm Dr F. Perry Wilson from the Yale School of Medicine. Two-thirds of you reading this will know the feeling. It starts with a numb, tingly, feeling in the lip. A day or so later, some redness, some swelling, and then, yup, a cold sore. It's a little frustrating, maybe a little embarrassing, but you wait it out for a few days and it goes away. No big deal, right? Except for the fact that multiple studies suggest that cold sores might increase your risk for Alzheimer's disease. Cold sores come from a viral infection, specifically herpes simplex virus 1 (HSV-1). There are multiple herpesviruses, which are all DNA viruses and include HSV-2 which causes the sexually transmitted infection; though, to be fair, both HSV-1 and -2 can lead to both types of infections. Varicella — the virus that causes chicken pox and shingles, Ebstein-Barr virus, CMV — are all herpesviruses. If you're human, you have almost certainly been infected by at least one. In any case, HSV-1 is one of the most common viral infections in the world. It's estimated that about two-thirds of the adult population are infected. Unlike other viruses, such as flu or coronavirus, herpesviruses are incredibly difficult to completely fight off from your body. They get around immune surveillance by hiding out in the nucleus of other cells as just an innocuous bundle of DNA. This latent phase is asymptomatic. It lies dormant until, for reasons that are still not entirely clear, the DNA bundle loosens a bit and the cellular machinery turns those instructions into the proteins that make up new virus particles and boom — outbreak. The immune system gets revved up, the outbreak is contained, and the cycle repeats. What does this all have to do with Alzheimer's disease? I was inspired to dig into this a bit because of a study appearing this week in BMJ Open , which suggests that HSV-1 infection nearly doubles the risk of Alzheimer's. Let me run through the study's findings and then we can figure out if this makes any sense at all. Researchers used the IQVIA PharMetrics Plus database to conduct the study. This is basically a large administrative claims database that covers much of the United States. It basically aggregates all the billing codes for medical care and medications from a bunch of commercial insurers; there are more than 200 million individuals represented in the file. From those, they found 344,628 individuals who were diagnosed with Alzheimer's disease. For controls, they identified another 344,628 individuals with the same age, gender, region of the country, date of entry into the database, and — to account for contact with the medical system — the number of inpatient and outpatient visits. Despite that, the groups were not exactly comparable. The individuals who would go on to develop Alzheimer's disease had a greater number of comorbidities, for example. But the kicker of the study — the headline — is this finding. People with Alzheimer's disease were twice as likely to have HSV-1 compared with the controls. After accounting for the differences between them, infection with HSV-1 increased the odds of subsequently developing Alzheimer's disease by 80%. Did you catch the problem with this graph? Take a look at the Y-axis. That's on the percentage scale. Sure, the people who went on to develop Alzheimer's disease had double the rate of HSV-1 infection, but the raw number is 0.44% vs 0.24%. Didn't I tell you at the beginning that about two-thirds of us are infected with HSV-1? That's quite a bit higher than 0.44%. What is going on here? Welcome to the world of administrative data. The problem here is that the researchers could only identify people with HSV-1 based on some provider diagnosing them with HSV-1. More than that, entering a billing code for HSV-1. Have you ever had a cold sore? Do you know whether your doctor added that to your medical history and billed insurance for it? Probably not. So we're missing an enormous number of infections here, and that calls the whole conclusion into question. Now, you might say, sure, doctors aren't diagnosing the vast majority of HSV-1 cases, but surely this is true both for people who go on to develop Alzheimer's and for those who don't, and therefore the inference is valid. Maybe. But I'd feel better if we were talking about missing something like 10% of diagnoses instead of 99% like we are here. I don't want to discount this too much, though. The paper has some other interesting findings. For instance, there was also a higher rate of HSV-2 and varicella infection among those who developed Alzheimer's disease; those are the other herpesviruses that infect nerve cells. There was no difference in rates of cytomegalovirus infection — another herpesvirus, but one that infects monocytes instead of nerve cells. But let's say we believe the link between HSV and Alzheimer's, what can we do about it? The authors hypothesized that, if HSV is causative of Alzheimer's, treatment with antivirals would reduce the risk of Alzheimer's disease. And since prescription information was present in the dataset, they could model this. Sure enough, those treated with antivirals were less likely — about 17% less likely — to develop Alzheimer's disease. This is interesting to me. In general, when you look at people who are treated for a condition, you can assume they had a more severe form of the condition (short of the treatment being done in the context of a randomized trial). Basically, people who get treated tend to be sicker than people who don't get treated, and so, in general, you see worse outcomes in the treated group — a stubborn problem in observational data called confounding by indication. Here, we see the opposite, which adds some weight to the argument. So, despite the poor capture of HSV-1 infections, the link could be real. Some other studies support this hypothesis. Alzheimer's disease is characterized by amyloid plaque deposition in the brain. Some mouse studies have shown that HSV induces the formation of amyloid plaques as an immune response and impairs the mouse's cognitive ability. This study prospectively studied 1000 Swedish older adults over time and measured antibodies to HSV: 82% of people had those antibodies which comports with what we would expect. Still, those with the antibodies had about twice the risk of developing dementia as those without. The authors of the paper in BMJ Open suggest 'antiherpetic therapies as potentially protective for AD-related dementia.' That feels like a bit of a leap to me at this point, and I will point out that this paper was funded by Gilead Sciences who have quite a few antivirals on the market and a new anti-herpetic drug that has recently completed phase 1a testing— so… grains of salt. Still, for those who suffer from cold sores, a study like this may push you a bit towards treatment, at least during an outbreak. Short-term valacyclovir is relatively safe and reduces the duration of the cold sore by about a day, which is nice. But if it reduces your risk of dementia as well, well, it might be a no-brainer.
