NewsMakers
Scientists find evidence that novel coronavirus infects the mouth’s cells
“When infected saliva is swallowed or tiny particles of it are inhaled, we think it can potentially transmit SARS-CoV-2 further into our throats, our lungs, or even our guts.”
An international team of scientists has found evidence that SARS-CoV-2, the virus that causes COVID-19, infects cells in the mouth. While it’s well known that the upper airways and lungs are primary sites of SARS-CoV-2 infection, there are clues the virus can infect cells in other parts of the body, such as the digestive system, blood vessels, kidneys and, as this new study shows, the mouth.
The potential of the virus to infect multiple areas of the body might help explain the wide-ranging symptoms experienced by COVID-19 patients, including oral symptoms such as taste loss, dry mouth and blistering. Moreover, the findings point to the possibility that the mouth plays a role in transmitting SARS-CoV-2 to the lungs or digestive system via saliva laden with virus from infected oral cells. A better understanding of the mouth’s involvement could inform strategies to reduce viral transmission within and outside the body. The team was led by researchers at the National Institutes of Health and the University of North Carolina at Chapel Hill.
“Due to NIH’s all-hands-on-deck response to the pandemic, researchers at the National Institute of Dental and Craniofacial Research were able to quickly pivot and apply their expertise in oral biology and medicine to answering key questions about COVID-19,” said NIDCR Director Rena D’Souza, D.D.S., M.S., Ph.D. “The power of this approach is exemplified by the efforts of this scientific team, who identified a likely role for the mouth in SARS-CoV-2 infection and transmission, a finding that adds to knowledge critical for combatting this disease.”
The study, published online March, 25, 2021 in Nature Medicine, was led by Blake M. Warner, D.D.S., Ph.D., M.P.H., assistant clinical investigator and chief of NIDCR’s Salivary Disorders Unit, and Kevin M. Byrd, D.D.S., Ph.D., at the time an assistant professor in the Adams School of Dentistry at the University of North Carolina at Chapel Hill. Byrd is now an Anthony R. Volpe Research Scholar at the American Dental Association Science and Research Institute. Ni Huang, Ph.D., of the Wellcome Sanger Institute in Cambridge, U.K., and Paola Perez, Ph.D., of NIDCR, were co-first authors.
Researchers already know that the saliva of people with COVID-19 can contain high levels of SARS-CoV-2, and studies suggest that saliva testing is nearly as reliable as deep nasal swabbing for diagnosing COVID-19. What scientists don’t entirely know, however, is where SARS-CoV-2 in the saliva comes from. In people with COVID-19 who have respiratory symptoms, virus in saliva possibly comes in part from nasal drainage or sputum coughed up from the lungs. But according to Warner, that may not explain how the virus gets into the saliva of people who lack those respiratory symptoms.
“Based on data from our laboratories, we suspected at least some of the virus in saliva could be coming from infected tissues in the mouth itself,” Warner said.
To explore this possibility, the researchers surveyed oral tissues from healthy people to identify mouth regions susceptible to SARS-CoV-2 infection. Vulnerable cells contain RNA instructions for making “entry proteins” that the virus needs to get into cells. RNA for two key entry proteins–known as the ACE2 receptor and the TMPRSS2 enzyme–was found in certain cells of the salivary glands and tissues lining the oral cavity. In a small portion of salivary gland and gingival (gum) cells, RNA for both ACE2 and TMPRSS2 was expressed in the same cells. This indicated increased vulnerability because the virus is thought to need both entry proteins to gain access to cells.
“The expression levels of the entry factors are similar to those in regions known to be susceptible to SARS-CoV-2 infection, such as the tissue lining the nasal passages of the upper airway,” Warner said.
Once the researchers had confirmed that parts of the mouth are susceptible to SARS-CoV-2, they looked for evidence of infection in oral tissue samples from people with COVID-19. In samples collected at NIH from COVID-19 patients who had died, SARS-CoV-2 RNA was present in just over half of the salivary glands examined. In salivary gland tissue from one of the people who had died, as well as from a living person with acute COVID-19, the scientists detected specific sequences of viral RNA that indicated cells were actively making new copies of the virus–further bolstering the evidence for infection.
Once the team had found evidence of oral tissue infection, they wondered whether those tissues could be a source of the virus in saliva. This appeared to be the case. In people with mild or asymptomatic COVID-19, cells shed from the mouth into saliva were found to contain SARS-CoV-2 RNA, as well as RNA for the entry proteins.
To determine if virus in saliva is infectious, the researchers exposed saliva from eight people with asymptomatic COVID-19 to healthy cells grown in a dish. Saliva from two of the volunteers led to infection of the healthy cells, raising the possibility that even people without symptoms might transmit infectious SARS-CoV-2 to others through saliva.
Finally, to explore the relationship between oral symptoms and virus in saliva, the team collected saliva from a separate group of 35 NIH volunteers with mild or asymptomatic COVID-19. Of the 27 people who experienced symptoms, those with virus in their saliva were more likely to report loss of taste and smell, suggesting that oral infection might underlie oral symptoms of COVID-19.
Taken together, the researchers said, the study’s findings suggest that the mouth, via infected oral cells, plays a bigger role in SARS-CoV-2 infection than previously thought.
“When infected saliva is swallowed or tiny particles of it are inhaled, we think it can potentially transmit SARS-CoV-2 further into our throats, our lungs, or even our guts,” said Byrd.
More research will be needed to confirm the findings in a larger group of people and to determine the exact nature of the mouth’s involvement in SARS-CoV-2 infection and transmission within and outside the body.
“By revealing a potentially underappreciated role for the oral cavity in SARS-CoV-2 infection, our study could open up new investigative avenues leading to a better understanding of the course of infection and disease. Such information could also inform interventions to combat the virus and alleviate oral symptoms of COVID-19,” Warner said.
NewsMakers
At-home brain stimulation prevents depression relapse in 3 out of 4 patients, study finds
As up to 85% of people with depression experience relapse during treatment, effective tools for relapse prevention are lagging.
A study, and largest of its kind, has found that at-home brain stimulation can prevent relapse of major depressive disorder in 75% of patients. Published in the Journal of Affective Disorders, the PSYLECT study tracked the long-term effects of home-based transcranial direct current stimulation (tDCS) therapy combined with online behavioral support. The findings revealed that non-drug, at-home treatment could help many patients maintain recovery from depression over time.
In the study, participants who had completed their initial depression treatment had to use at-home brain stimulation twice a week for six months.
Researchers monitored their progress to see whether the therapy could prevent relapse without ongoing clinical support. By the end of the follow-up period, only six of the 71 patients experienced a return of depressive symptoms, while 11 discontinued treatment.
The results showed that most participants maintained recovery using brain stimulation therapy alone, without the need for in-person visits or additional interventions.
As up to 85% of people with depression experience relapse during treatment, effective tools for relapse prevention are lagging.
According to the study, at-home and remotely supervised tDCS therapy can be an effective and scalable option: it achieves results comparable to in-clinic treatment, but can increase access and lower costs, as it doesn’t require clinic visits to receive therapy sessions.
“Home-based brain stimulation bridges a major treatment gap, helping patients sustain long-term recovery after antidepressants or psychotherapy,” said Erin Lee, CEO of Flow Neuroscience, the company behind a tDCS device for depression used in the study. “Many people struggle to pay for visits or travelling to the clinic, or simply are too busy to attend several sessions a week. This is when at-home therapy comes to the rescue.”
Erin Lee added that at-home tDCS-based relapse prevention can be cost-effective for clinics, too, as it reduces waiting times and frees up clinicians.
For patients, another benefit of at-home treatment is high adherence.
“Many people with a history of depression might find it easier to stick to home-based therapy, as it’s less effort compared to regular in-clinic visits,” noted Dr. Kultar Singh Garcha, a GP and Medical Director at Flow Neuroscience. “Even months into treatment, many patients still feel physically and emotionally exhausted, so lowering the effort can help them keep going.”
Beyond accessibility and scalability, researchers found at-home brain stimulation to be safe and well-tolerated, with minimal side effects like scalp itching or headaches. By the end of the study, 40% of participants reported no adverse events at all.
The study was led by the University of São Paulo Medical School and conducted in collaboration with the Ludwig-Maximilians University in Munich, Germany, as well as the University of Ghent, Belgium, Spaulding Rehabilitation Hospital, and Massachusetts General Hospital.
Flow Neuroscience’s medical device, used in the study, is CE-certified and has regulatory approval for depression treatment in the UK, EU, Australia, Switzerland, Hong Kong, and other countries. It is backed by both clinical studies and real-world data of over 50,000 users.
By delivering gentle electrical currents to the brain, the headset regulates activity in the prefrontal cortex, the part of the brain involved in mood regulation and stress response. It is often underactive in people with depression.
“For decades, relapse has been one of the biggest challenges in depression treatment, but this is finally changing now,” said Erin Lee. “We are certain that with home-based brain stimulation therapy, effective and non-drug relapse prevention will become a new mental health care standard.”
NewsMakers
Millennials and Gen Zs prioritize health, purpose, financial independence, but health and wellness gaps persist
Younger Filipinos are placing greater emphasis on healthspan, purpose, and financial independence. However, the study also revealed that while 83% of young respondents have good knowledge about health and wellness, only 76% say they are taking sufficient action to consistently practice healthy habits.
While millennials and Gen Zs in the Philippines are reshaping what it means to live well and live long, significant gaps between awareness and action jeopardize their health, wellness, and longevity aspirations, a new study by Manulife Philippines has found.
According to “#FYP: Future-proofing Young Pinoys: Examining Health and Longevity Perspectives, Sentiments, and Aspirations of Millennials and Gen Zs,” which was conducted among 500 respondents across the Philippines, younger Filipinos are placing greater emphasis on healthspan, purpose, and financial independence. However, the study also revealed that while 83% of young respondents have good knowledge about health and wellness, only 76% say they are taking sufficient action to consistently practice healthy habits.
“With a median age of 26.1, the Philippines has one of the youngest populations in Asia. Our latest study highlights the need to support younger generations in translating their health, wellness, and longevity aspirations into meaningful action. We found that millennials and Gen Zs are motivated to live healthier lives, but barriers like stress, excessive screen time, and sleep deprivation, among many others are holding them back from achieving this goal,” said Rahul Hora, President and Chief Executive Officer, Manulife Philippines.
Motivated to be healthy, but stress gets in the way; Millennial women among the most affected
The study found that millennials and Gen Zs are not short of motivation to pursue their health and wellness goals. While 64% said they are pursuing health to avoid getting sick, and 44% said they want to minimize potential medical expenses, many are equally driven by their personal well-being and self-image about feeling and looking good: 44% said they want to look good or fit, and 43% said they want to look youthful.
Younger Filipinos, especially women, are also putting more focus on healthspan, or the number of the years we live healthily, over lifespan. According to the survey, 60% of female respondents prefer to prolong their healthspans, while 53% of males prefer to prolong their lifespans.
Filipino millennials and Gen Zs face notable health and wellness gaps, from monitoring to their actual wellness behaviors:
- Young Filipinos show significant gaps in health monitoring (awareness vs what they actually monitor), particularly in mobility (24%), nutrition (23%), and cholesterol levels (20%). Gender differences are evident, with young women struggling more with nutritional monitoring (27%) and young men facing greater challenges in mobility monitoring (28%).
- Many young Filipinos find it difficult to consistently maintain healthy sleeping habits (20%), achieve work-life balance (19%), and follow a balanced diet (15%). Women report a larger gap in achieving work-life balance at 22%, compared to the 15% gap among men.
- Stress is the most prominent barrier to wellness, affecting 64% of respondents. Millennials report higher stress levels than Gen Zs (69% vs. 58%), and women are more affected than men (73% vs. 55%). Notably, 76% of millennial women say stress prevents them from pursuing their desired wellbeing—the highest among all generational and gender groups.
- Modern lifestyle habits further compound these issues, with excessive screen time impacting 48% and sleep deprivation affecting 45% of young Filipinos. Trends such as “bedrotting” and “doomscrolling” reflect how contemporary behaviors are undermining their wellness goals.
“We’re seeing that for young Filipinos, intent alone isn’t sufficient. While many are motivated to pursue healthier lives, they’re facing a complex mix of stressors and lifestyle gaps, which make it difficult to follow through. These habits quietly derail their ability to prioritize wellness. That’s why the next step is to find ways to embed wellness into their daily routine. By offering health and wellness-focused programs and collaborations with likeminded partners, we are helping them bridge the gap between intention and action, turning wellness goals into sustainable, everyday behaviors supporting their long-term health and longevity aspirations,” added Hora.
Younger Filipinos view age positively and prioritize attaining purpose and living independently than being illness-free
According to the study, 96% of millennials and Gen Zs surveyed believe aging is a natural process that should be embraced with positivity, while 91% of the respondents believe that living a meaningful life is more important than living a long one. The study revealed a striking perspective on aging priorities, with 83% of respondents believing that living independently and being able to do things that matter most to them is more important than being illness-free.
Millennials surveyed focus more on physical health and family relationships as they age. Gen Zs, on the other hand, lean toward self-discovery, purpose, and making an impact. Only 13% of both generations consider maximizing lifespan as a top priority, with men showing slightly higher interest (17%) compared to women (8%).
“The findings reveal that young Filipinos see aging not as decline, but as a chance to live with purpose and independence,” Hora said. “It is therefore crucial that we create opportunities and support systems for them to live better at every stage of their lives. This means investing in holistic wellness programs, accessible financial health education, as well as tools that address both physical and mental needs, tailored especially for younger generations navigating various stressors of the modern world.”
“As one of the country’s longest-serving insurers, Manulife Philippines is deeply committed to supporting younger generations of Filipinos in their journey toward financial independence and longevity. Through our innovative insurance and investment solutions, and our nationwide network of over 10,000 professional financial advisors, we aim to empower millennials and Gen Zs to live fuller, healthier lives with purpose and confidence as they age,” said Hora.
Financial independence: Younger Filipinos’ ultimate longevity concern
When it comes to living a longer life but also “adding life to years,” financial security tops the list of concerns for both generations. Among the respondents, 74% believe that longevity is a blessing only if they have sufficient financial resources, with running out of money being their greatest worry (61%). Millennials and Gen Zs agree that mental health is a top longevity concern (36% and 47%, respectively). Millennials surveyed are more concerned about keeping ties with children (37%), while Gen Zs are more concerned about living their desired lifestyle (39%).
Gaining financial independence is also a top longevity priority for young Filipinos (52%), followed by family relationships (36%) and physical health (33%). Women, however, prioritize financial independence significantly more than men (60% vs. 44%). This gender gap reflects broader structural realities women face in the Philippines. Despite having longer life expectancies (69.9 vs 63.4), women have lower labor force participation (52.9% vs 76.3%) and are prone to career interruptions due to family and caregiving responsibilities. These factors make financial independence especially urgent for women, who must plan for longer retirement years with potentially fewer financial opportunities.
Financial planning remains one of the many challenges the youth face. Gen Zs surveyed estimate needing PHP22.3 million to achieve financial independence upon retirement, while millennials estimate PHP18.4 million. Yet only 20% of respondents have very high confidence in achieving these goals. Despite the challenges, young Filipinos take proactive steps. Among those who prioritize financial independence, 65% save part of their income, 45% purchase insurance, and 43% actively broaden their financial knowledge. However, 68% admit that sustaining investments remains difficult.
“It’s encouraging to see today’s younger generations starting to take more proactive steps toward financial planning. We’re seeing a shift in mindset, where millennials and Gen Zs are actively saving, purchasing insurance, and expanding their financial literacy. These are promising signs,” said Aira Gaspar, President and Chief Executive Officer, Manulife Investments Philippines.
“The key now is to help them bridge the gap between intention and sustained action, through accessible, flexible investment strategies that evolve with their life stages, financial capabilities, and aspirations. By enabling them with the right tools and guidance, we can help turn financial independence into a tangible, achievable reality for our younger customers in the Philippines,” added Gaspar.
NewsMakers
Drinking any amount of alcohol likely increases dementia risk
Even light drinking—generally thought to be protective, based on observational studies—is unlikely to lower the risk, which rises in tandem with the quantity of alcohol consumed.
Drinking any amount of alcohol likely increases the risk of dementia, suggests the largest combined observational and genetic study to date, published online in BMJ Evidence Based Medicine.
Even light drinking—generally thought to be protective, based on observational studies—is unlikely to lower the risk, which rises in tandem with the quantity of alcohol consumed, the research indicates.
Current thinking suggests that there might be an ‘optimal dose’ of alcohol for brain health, but most of these studies have focused on older people and/or didn’t differentiate between former and lifelong non-drinkers, complicating efforts to infer causality, note the researchers.
To try and circumnavigate these issues and strengthen the evidence base, the researchers drew on observational data and genetic methods (Mendelian randomisation) from two large biological databanks for the entire ‘dose’ range of alcohol consumption.
These were the US Million Veteran Program (MVP), which includes people of European, African, and Latin American ancestry, and the UK Biobank (UKB), which includes people of predominantly European ancestry.
Participants who were aged 56–72 at baseline, were monitored from recruitment until their first dementia diagnosis, death, or the date of last follow-up (December 2019 for MVP and January 2022 for UKB), whichever came first. The average monitoring period was 4 years for the US group, and 12 for the UK group.
Alcohol consumption was derived from questionnaire responses—over 90% of participants said they drank alcohol—and the Alcohol Use Disorders Identification Test (AUDIT-C) clinical screening tool. This screens for hazardous drinking patterns, including the frequency of binge drinking (6 or more drinks at a time).
In all, 559,559 participants from both groups were included in observational analyses, 14,540 of whom developed dementia of any type during the monitoring period:10,564 in the US group; and 3976 in the UK group. And 48,034 died: 28,738 in the US group and 19,296 in the UK group.
Observational analyses revealed U-shaped associations between alcohol and dementia risk: compared with light drinkers (fewer than 7 drinks a week) a 41% higher risk was observed among non-drinkers and heavy drinkers consuming 40 or more drinks a week, rising to a 51% higher risk among those who were alcohol dependent.
Mendelian randomisation genetic analyses drew on key data from multiple large individual genome-wide association studies (GWAS) of dementia, involving a total of 2.4 million participants to ascertain lifetime (rather than current) genetically predicted risks.
Mendelian randomisation leverages genetic data, minimising the impact of other potentially influential factors, to estimate causal effects: genomic risk for a trait (in this case, alcohol consumption) essentially stands in for the trait itself.
Three genetic measures related to alcohol use were used as different exposures, to study the impact on dementia risk of alcohol quantity, as well as problematic and dependent drinking.
These exposures were: self-reported weekly drinks (641 independent genetic variants); problematic ‘risky’ drinking (80 genetic variants); and alcohol dependency (66 genetic variants).
Higher genetic risk for all 3 exposure levels was associated with an increased risk of dementia, with a linear increase in dementia risk the higher the alcohol consumption.
For example, an extra 1-3 drinks a week was associated with a 15% higher risk. And a doubling in the genetic risk of alcohol dependency was associated with a 16% increase in dementia risk.
But no U-shaped association was found between alcohol intake and dementia, and no protective effects of low levels of alcohol intake were observed. Instead, dementia risk steadily increased with more genetically predicted drinking.
What’s more, those who went on to develop dementia typically drank less over time in the years preceding their diagnosis, suggesting that reverse causation—whereby early cognitive decline leads to reduced alcohol consumption—underlies the supposed protective effects of alcohol found in previous observational studies, say the researchers.
They acknowledge that a principal limitation of their findings is that the strongest statistical associations were found in people of European ancestry, because of the numbers of participants of this ethnic heritage studied. Mendelian randomisation also relies on assumptions that can’t be verified, they add.
Nevertheless, they suggest that their findings “challenge the notion that low levels of alcohol are neuroprotective.”
And they conclude: “Our study findings support a detrimental effect of all types of alcohol consumption on dementia risk, with no evidence supporting the previously suggested protective effect of moderate drinking.
“The pattern of reduced alcohol use before dementia diagnosis observed in our study underscores the complexity of inferring causality from observational data, especially in ageing populations.
“Our findings highlight the importance of considering reverse causation and residual confounding in studies of alcohol and dementia, and they suggest that reducing alcohol consumption may be an important strategy for dementia prevention.”
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