Genes shape our response to Covid virus
Important findings are starting to emerge from research on how genes shape the human response to the Covid virus.
From infections with no symptoms to why men are more likely to be hospitalized in the ICU and die of COVID-19, new research shows that your genes play a significant role
Early in the pandemic, genetic research focused on the virus because it was readily available. Plus, the virus contains only 30,000 bases in a dozen functional genes, so it's relatively easy and affordable to sequence. Additionally, the rapid mutation of the virus and its ability to escape antibody control fueled waves of different variants and provided a reason to follow viral genetics.
In comparison, there are many more genes of the human immune system and cellular functions that affect viral replication, with about 3.2 billion base pairs. Human studies require samples from large numbers of people, the analysis of each sample is vastly more complex, and sophisticated computer analysis often is required to make sense of the raw data. All of this takes time and large amounts of money, but important findings are beginning to emerge.
Asymptomatics
About half the people exposed to SARS-CoV-2, the virus that causes the COVID-19 disease, never develop symptoms of this disease, or their symptoms are so mild they often go unnoticed. One piece of understanding the phenomena came when researchers showed that exposure to OC43, a common coronavirus that results in symptoms of a cold, generates immune system T cells that also help protect against SARS-CoV-2.
Jill Hollenbach, an immunologist at the University of California at San Francisco, sought to identify the gene behind that immune protection. Most COVID-19 genetic studies are done with the most seriously ill patients because they are hospitalized and thus available. “But 99 percent of people who get it will never see the inside of a hospital for COVID-19,” she says. “They are home, they are not interacting with the health care system.”
Early in the pandemic, when most labs were shut down, she tapped into the National Bone Marrow Donor Program database. It contains detailed information on donor human leukocyte antigens (HLAs), key genes in the immune system that must match up between donor and recipient for successful transplants of marrow or organs. Each HLA can contain alleles, slight molecular differences in the DNA of the HLA, which can affect its function. Potential HLA combinations can number in the tens of thousands across the world, says Hollenbach, but each person has a smaller number of those possible variants.
She teamed up with the COVID-19 Citizen Science Study a smartphone-based study to track COVID-19 symptoms and outcomes, to ask persons in the bone marrow donor registry about COVID-19. The study enlisted more than 30,000 volunteers. Those volunteers already had their HLAs annotated by the registry, and 1,428 tested positive for the virus.
Analyzing five key HLAs, she found an allele in the gene HLA-B*15:01 that was significantly overrepresented in people who didn’t have any symptoms. The effect was even stronger if a person had inherited the allele from both parents; these persons were “more than eight times more likely to remain asymptomatic than persons who did not carry the genetic variant,” she says. Altogether this HLA was present in about 10 percent of the general European population but double that percentage in the asymptomatic group. Hollenbach and her colleagues were able confirm this in other different groups of patients.
What made the allele so potent against SARS-CoV-2? Part of the answer came from x-ray crystallography. A key element was the molecular shape of parts of the cold virus OC43 and SARS-CoV-2. They were virtually identical, and the allele could bind very tightly to them, present their molecular antigens to T cells, and generate an extremely potent T cell response to the viruses. And “for whatever reasons that generated a lot of memory T cells that are going to stick around for a long time,” says Hollenbach. “This T cell response is very early in infection and ramps up very quickly, even before the antibody response.”
Understanding the genetics of the immune response to SARS-CoV-2 is important because it provides clues into the conditions of T cells and antigens that support a response without any symptoms, she says. “It gives us an opportunity to think about whether this might be a vaccine design strategy.”
Dead men
A researcher at the Leibniz Institute of Virology in Hamburg Germany, Guelsah Gabriel, was drawn to a question at the other end of the COVID-19 spectrum: why men more likely to be hospitalized and die from the infection. It wasn't that men were any more likely to be exposed to the virus but more likely, how their immune system reacted to it
Several studies had noted that testosterone levels were significantly lower in men hospitalized with COVID-19. And, in general, the lower the testosterone, the worse the prognosis. A year after recovery, about 30 percent of men still had lower than normal levels of testosterone, a condition known as hypogonadism. Most of the men also had elevated levels of estradiol, a female hormone (https://pubmed.ncbi.nlm.nih.gov/34402750/).
Every cell has a sex, expressing receptors for male and female hormones on their surface. Hormones docking with these receptors affect the cells' internal function and the signals they send to other cells. The number and role of these receptors varies from tissue to tissue.
Gabriel began her search by examining whole exome sequences, the protein-coding part of the genome, for key enzymes involved in the metabolism of sex hormones. The research team quickly zeroed in on CYP19A1, an enzyme that converts testosterone to estradiol. The gene that produces this enzyme has a number of different alleles, the molecular variants that affect the enzyme's rate of metabolizing the sex hormones. One genetic variant, CYP19A1 (Thr201Met), is typically found in 6.2 percent of all people, both men and women, but remarkably, they found it in 68.7 percent of men who were hospitalized with COVID-19.
Lung surprise
Lungs are the tissue most affected in COVID-19 disease. Gabriel wondered if the virus might be affecting expression of their target gene in the lung so that it produces more of the enzyme that converts testosterone to estradiol. Studying cells in a petri dish, they saw no change in gene expression when they infected cells of lung tissue with influenza and the original SARS-CoV viruses that caused the SARS outbreak in 2002. But exposure to SARS-CoV-2, the virus responsible for COVID-19, increased gene expression up to 40-fold, Gabriel says.
Did the same thing happen in humans? Autopsy examination of patients in three different cites found that “CYP19A1 was abundantly expressed in the lungs of COVID-19 males but not those who died of other respiratory infections,” says Gabriel. This increased enzyme production led likely to higher levels of estradiol in the lungs of men, which “is highly inflammatory, damages the tissue, and can result in fibrosis or scarring that inhibits lung function and repair long after the virus itself has disappeared.” Somehow the virus had acquired the capacity to upregulate expression of CYP19A1.
Only two COVID-19 positive females showed increased expression of this gene. The menopause status of these women, or whether they were on hormone replacement therapy was not known. That could be important because female hormones have a protective effect for cardiovascular disease, which women often lose after going through menopause, especially if they don’t start hormone replacement therapy. That sex-specific protection might also extend to COVID-19 and merits further study.
The team was able to confirm their findings in golden hamsters, the animal model of choice for studying COVID-19. Testosterone levels in male animals dropped 5-fold three days after infection and began to recover as viral levels declined. CYP19A1 transcription increased up to 15-fold in the lungs of the male but not the females. The study authors wrote, “Virus replication in the male lungs was negatively associated with testosterone levels.”
The medical community studying COVID-19 has slowly come to recognize the importance of adipose tissue, or fat cells. They are known to express abundant levels of CYP19A1 and play a significant role as metabolic tissue in COVID-19. Gabriel adds, “One of the key findings of our study is that upon SARS-CoV-2 infection, the lung suddenly turns into a metabolic organ by highly expressing” CYP19A1.
She also found evidence that SARS-CoV-2 can infect the gonads of hamsters, thereby likely depressing circulating levels of sex hormones. The researchers did not have autopsy samples to confirm this in humans, but others have shown that the virus can replicate in those tissues.
A possible treatment
Back in the lab, substituting low and high doses of testosterone in SARS-COV-2 infected male hamsters had opposite effects depending on testosterone dosage used. Gabriel says that hormone levels can vary so much, depending on health status and age and even may change throughout the day, that “it probably is much better to inhibit the enzyme” produced by CYP19A1 than try to balance the hormones.
Results were better with letrozole, a drug approved to treat hypogonadism in males, which reduces estradiol levels. The drug also showed benefit in male hamsters in terms of less severe disease and faster recovery. She says more details need to be worked out in using letrozole to treat COVID-19, but they are talking with hospitals about clinical trials of the drug.
Gabriel has proposed a four hit explanation of how COVID-19 can be so deadly for men: the metabolic quartet. First is the genetic risk factor of CYP19A1 (Thr201Met), then comes SARS-CoV-2 infection that induces even greater expression of this gene and the deleterious increase of estradiol in the lung. Age-related hypogonadism and the heightened inflammation of obesity, known to affect CYP19A1 activity, are contributing factors in this deadly perfect storm of events.
Studying host genetics, says Gabriel, can reveal new mechanisms that yield promising avenues for further study. It’s also uniting different fields of science into a new, collaborative approach they’re calling “infection endocrinology,” she says.
The Friday Five Weekly Roundup in Health Research
In this week's Friday Five, the right facial expression for your mental health. Plus, can virtual reality reduce pain? Lab made blood vessels. Gene editing muscles to lower blood sugar. And a magic ingredient coming from exhaust vents.
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Listen on Apple | Listen on Spotify | Listen on Stitcher | Listen on Amazon | Listen on Google
Here are the promising studies covered in this week's Friday Five:
- The right facial expression for your mental health
- Can virtual reality reduce pain?
- Lab made blood vessels
- Gene editing muscles to lower blood sugar
- A magic ingredient coming from exhaust vents
Leaders at Google and other companies are trying to get workers to return to the office, saying remote and hybrid work disrupt work-life boundaries and well-being. These arguments conflict with research on remote work and wellness.
Many leaders at top companies are trying to get workers to return to the office. They say remote and hybrid work are bad for their employees’ mental well-being and lead to a sense of social isolation, meaninglessness, and lack of work-life boundaries, so we should just all go back to office-centric work.
One example is Google, where the company’s leadership is defending its requirement of mostly in-office work for all staff as necessary to protect social capital, meaning people’s connections to and trust in one another. That’s despite a survey of over 1,000 Google employees showing that two-thirds feel unhappy about being forced to work in the office three days per week. In internal meetings and public letters, many have threatened to leave, and some are already quitting to go to other companies with more flexible options.
Last month, GM rolled out a policy similar to Google’s, but had to backtrack because of intense employee opposition. The same is happening in some places outside of the U.S. For instance, three-fifths of all Chinese employers are refusing to offer permanent remote work options, according to a survey this year from The Paper.
For their claims that remote work hurts well-being, some of these office-centric traditionalists cite a number of prominent articles. For example, Arthur Brooks claimed in an essay that “aggravation from commuting is no match for the misery of loneliness, which can lead to depression, substance abuse, sedentary behavior, and relationship damage, among other ills.” An article in Forbes reported that over two-thirds of employees who work from home at least part of the time had trouble getting away from work at the end of the day. And Fast Company has a piece about how remote work can “exacerbate existing mental health issues” like depression and anxiety.
For his part, author Malcolm Gladwell has also championed a swift return to the office, saying there is a “core psychological truth, which is we want you to have a feeling of belonging and to feel necessary…I know it’s a hassle to come into the office, but if you’re just sitting in your pajamas in your bedroom, is that the work life you want to live?”
These arguments may sound logical to some, but they fly in the face of research and my own experience as a behavioral scientist and as a consultant to Fortune 500 companies. In these roles, I have seen the pitfalls of in-person work, which can be just as problematic, if not more so. Remote work is not without its own challenges, but I have helped 21 companies implement a series of simple steps to address them.
Research finds that remote work is actually better for you
The trouble with the articles described above - and claims by traditionalist business leaders and gurus - stems from a sneaky misdirection. They decry the negative impact of remote and hybrid work for wellbeing. Yet they gloss over the damage to wellbeing caused by the alternative, namely office-centric work.
It’s like comparing remote and hybrid work to a state of leisure. Sure, people would feel less isolated if they could hang out and have a beer with their friends instead of working. They could take care of their existing mental health issues if they could visit a therapist. But that’s not in the cards. What’s in the cards is office-centric work. That means the frustration of a long commute to the office, sitting at your desk in an often-uncomfortable and oppressive open office for at least 8 hours, having a sad desk lunch and unhealthy snacks, sometimes at an insanely expensive cost and, for making it through this series of insults, you’re rewarded with more frustration while commuting back home.
In a 2022 survey, the vast majority of respondents felt that working remotely improved their work-life balance. Much of that improvement stemmed from saving time due to not needing to commute and having a more flexible schedule.
So what happens when we compare apples to apples? That’s when we need to hear from the horse’s mouth: namely, surveys of employees themselves, who experienced both in-office work before the pandemic, and hybrid and remote work after COVID struck.
Consider a 2022 survey by Cisco of 28,000 full-time employees around the globe. Nearly 80 percent of respondents say that remote and hybrid work improved their overall well-being: that applies to 83 percent of Millennials, 82 percent of Gen Z, 76 percent of Gen Z, and 66 percent of Baby Boomers. The vast majority of respondents felt that working remotely improved their work-life balance.
Much of that improvement stemmed from saving time due to not needing to commute and having a more flexible schedule: 90 percent saved 4 to 8 hours or more per week. What did they do with that extra time? The top choice for almost half was spending more time with family, friends and pets, which certainly helped address the problem of isolation from the workplace. Indeed, three-quarters of them report that working from home improved their family relationships, and 51 percent strengthened their friendships. Twenty percent used the freed up hours for self-care.
Of the small number who report their work-life balance has not improved or even worsened, the number one reason is the difficulty of disconnecting from work, but 82 percent report that working from anywhere has made them happier. Over half say that remote work decreased their stress levels.
Other surveys back up Cisco’s findings. For example, a 2022 Future Forum survey compared knowledge workers who worked full-time in the office, in a hybrid modality, and fully remote. It found that full-time in-office workers felt the least satisfied with work-life balance, hybrid workers were in the middle, and fully remote workers felt most satisfied. The same distribution applied to questions about stress and anxiety. A mental health website called Tracking Happiness found in a 2022 survey of over 12,000 workers that fully remote employees report a happiness level about 20 percent greater than office-centric ones. Another survey by CNBC in June found that fully remote workers are more often very satisfied with their jobs than workers who are fully in-person.
Academic peer-reviewed research provides further support. Consider a 2022 study published in the International Journal of Environmental Research and Public Health of bank workers who worked on the same tasks of advising customers either remotely or in-person. It found that fully remote workers experienced higher meaningfulness, self-actualization, happiness, and commitment than in-person workers. Another study, published by the National Bureau of Economic Research, reported that hybrid workers, compared to office-centric ones, experienced higher satisfaction with work and had 35 percent more job retention.
What about the supposed burnout crisis associated with remote work? Indeed, burnout is a concern. A survey by Deloitte finds that 77 percent of workers experienced burnout at their current job. Gallup came up with a slightly lower number of 67 percent in its survey. But guess what? Both of those surveys are from 2018, long before the era of widespread remote work.
By contrast, in a Gallup survey in late 2021, 58 percent of respondents reported less burnout. An April 2021 McKinsey survey found burnout in 54 percent of Americans and 49 percent globally. A September 2021 survey by The Hartford reported 61 percent burnout. Arguably, the increase in full or part-time remote opportunities during the pandemic helped to address feelings of burnout, rather than increasing them. Indeed, that finding aligns with the earlier surveys and peer-reviewed research suggesting remote and hybrid work improves wellbeing.
Remote work isn’t perfect – here’s how to fix its shortcomings
Still, burnout is a real problem for hybrid and remote workers, as it is for in-office workers. Employers need to offer mental health benefits with online options to help employees address these challenges, regardless of where they’re working.
Moreover, while they’re better overall for wellbeing, remote and hybrid work arrangements do have specific disadvantages around work-life separation. To address work-life issues, I advise my clients who I helped make the transition to hybrid and remote work to establish norms and policies that focus on clear expectations and setting boundaries.
For working at home and collaborating with others, there’s sometimes an unhealthy expectation that once you start your workday in your home office chair, and that you’ll work continuously while sitting there.
Some people expect their Slack or Microsoft Teams messages to be answered within an hour, while others check Slack once a day. Some believe email requires a response within three hours, and others feel three days is fine. As a result of such uncertainty and lack of clarity about what’s appropriate, too many people feel uncomfortable disconnecting and not replying to messages or doing work tasks after hours. That might stem from a fear of not meeting their boss’s expectations or not wanting to let their colleagues down.
To solve this problem, companies need to establish and incentivize clear expectations and boundaries. They should develop policies and norms around response times for different channels of communication. They also need to clarify work-life boundaries – for example, the frequency and types of unusual circumstances that will require employees to work outside of regular hours.
Moreover, for working at home and collaborating with others, there’s sometimes an unhealthy expectation that once you start your workday in your home office chair, and that you’ll work continuously while sitting there (except for your lunch break). That’s not how things work in the office, which has physical and mental breaks built in throughout the day. You took 5-10 minutes to walk from one meeting to another, or you went to get your copies from the printer and chatted with a coworker on the way.
Those and similar physical and mental breaks, research shows, decrease burnout, improve productivity, and reduce mistakes. That’s why companies should strongly encourage employees to take at least a 10-minute break every hour during remote work. At least half of those breaks should involve physical activity, such as stretching or walking around, to counteract the dangerous effects of prolonged sitting. Other breaks should be restorative mental activities, such as meditation, brief naps, walking outdoors, or whatever else feels restorative to you.
To facilitate such breaks, my client organizations such as the University of Southern California’s Information Sciences Institute shortened hour-long meetings to 50 minutes and half-hour meetings to 25 minutes, to give everyone – both in-person and remote workers – a mental and physical break and transition time.
Very few people will be reluctant to have shorter meetings. After that works out, move to other aspects of setting boundaries and expectations. Doing so will require helping team members get on the same page and reduce conflicts and tensions. By setting clear expectations, you’ll address the biggest challenge for wellbeing for remote and hybrid work: establishing clear work-life boundaries.