What to Know about the Fast-Spreading Delta Variant
A highly contagious form of the coronavirus known as the Delta variant is spreading rapidly and becoming increasingly prevalent around the world. First identified in India in December, Delta has now been identified in 111 countries.
In the United States, the variant now accounts for 83% of sequenced COVID-19 cases, said Rochelle Walensky, director of the Centers for Disease Control and Prevention, at a July 20 Senate hearing. In May, Delta was responsible for just 3% of U.S. cases. The World Health Organization projects that Delta will become the dominant variant globally over the coming months.
So, how worried should you be about the Delta variant? We asked experts some common questions about Delta.
What is a variant?
To understand Delta, it's helpful to first understand what a variant is. When a virus infects a person, it gets into your cells and makes a copy of its genome so it can replicate and spread throughout your body.
In the process of making new copies of itself, the virus can make a mistake in its genetic code. Because viruses are replicating all the time, these mistakes — also called mutations — happen pretty often. A new variant emerges when a virus acquires one or more new mutations and starts spreading within a population.
There are thousands of SARS-CoV-2 variants, but most of them don't substantially change the way the virus behaves. The variants that scientists are most interested in are known as variants of concern. These are versions of the virus with mutations that allow the virus to spread more easily, evade vaccines, or cause more severe disease.
"The vast majority of the mutations that have accumulated in SARS-CoV-2 don't change the biology as far as we're concerned," said Jennifer Surtees, a biochemist at the University of Buffalo who's studying the coronavirus. "But there have been a handful of key mutations and combinations of mutations that have led to what we're now calling variants of concern."
One of those variants of concern is Delta, which is now driving many new COVID-19 infections.
Why is the Delta variant so concerning?
"The reason why the Delta variant is concerning is because it's causing an increase in transmission," said Alba Grifoni, an infectious disease researcher at the La Jolla Institute for Immunology. "The virus is spreading faster and people — particularly those who are not vaccinated yet — are more prone to exposure."
The Delta variant has a few key mutations that make it better at attaching to our cells and evading the neutralizing antibodies in our immune system. These mutations have changed the virus enough to make it more than twice as contagious as the original SARS-CoV-2 virus that emerged in Wuhan and about 50% more contagious than the Alpha variant, previously known as B.1.1.7, or the U.K. variant.
These mutations were previously seen in other variants on their own, but it's their combination that makes Delta so much more infectious.
Do vaccines work against the Delta variant?
The good news is, the COVID-19 vaccines made by AstraZeneca, Johnson & Johnson, Moderna, and Pfizer still work against the Delta variant. They remain more than 90% effective at preventing hospitalizations and death due to Delta. While they're slightly less protective against disease symptoms, they're still very effective at preventing severe illness caused by the Delta variant.
"They're not as good as they were against the prior strains, but they're holding up pretty well," said Eric Topol, a physician and director of the Scripps Translational Research Institute, during a July 19 briefing for journalists.
Because Delta is better at evading our immune systems, it's likely causing more breakthrough infections — COVID-19 cases in people who are vaccinated. However, breakthrough infections were expected before the Delta variant became widespread. No vaccine is 100% effective, so breakthrough infections can happen with other vaccines as well. Experts say the COVID-19 vaccines are still working as expected, even if breakthrough infections occur. The majority of these infections are asymptomatic or cause only mild symptoms.
Should vaccinated people worry about the Delta variant?
Vaccines train our immune systems to protect us against infection. They do this by spurring the production of antibodies, which stick around in our bodies to help fight off a particular pathogen in case we ever come into contact with it.
But even if the new Delta variant slips past our neutralizing antibodies, there's another component of our immune system that can help overtake the virus: T cells. Studies are showing that the COVID-19 vaccines also galvanize T cells, which help limit disease severity in people who have been vaccinated.
"While antibodies block the virus and prevent the virus from infecting cells, T cells are able to attack cells that have already been infected," Grifoni said. In other words, T cells can prevent the infection from spreading to more places in the body. A study published July 1 by Grifoni and her colleagues found that T cells were still able to recognize mutated forms of the virus — further evidence that our current vaccines are effective against Delta.
Can fully vaccinated people spread the Delta variant?
Previously, scientists believed it was unlikely for fully vaccinated individuals with asymptomatic infections to spread Covid-19. But the Delta variant causes the virus to make so many more copies of itself inside the body, and high viral loads have been found in the respiratory tracts of people who are fully vaccinated. This suggests that vaccinated people may be able to spread the Delta variant to some degree.
If you have COVID-19 symptoms, even if you're fully vaccinated, you should get tested and isolate from friends and family because you could spread the virus.
What risk does Delta pose to unvaccinated people?
The Delta variant is behind a surge in cases in communities with low vaccination rates, and unvaccinated Americans currently account for 97% of hospitalizations due to COVID-19, according to Walensky. The best thing you can do right now to prevent yourself from getting sick is to get vaccinated.
Gigi Gronvall, an immunologist and senior scholar at the Johns Hopkins Center for Health Security, said in this week's "Making Sense of Science" podcast that it's especially important to get all required doses of the vaccine in order to have the best protection against the Delta variant. "Even if it's been more than the allotted time that you were told to come back and get the second, there's no time like the present," she said.
With more than 3.6 billion COVID-19 doses administered globally, the vaccines have been shown to be incredibly safe. Serious adverse effects are rare, although scientists continue to monitor for them.
Being vaccinated also helps prevent the emergence of new and potentially more dangerous variants. Viruses need to infect people in order to replicate, and variants emerge because the virus continues to infect more people. More infections create more opportunities for the virus to acquire new mutations.
Surtees and others worry about a scenario in which a new variant emerges that's even more transmissible or resistant to vaccines. "This is our window of opportunity to try to get as many people vaccinated as possible and get people protected so that so that the virus doesn't evolve to be even better at infecting people," she said.
Does Delta cause more severe disease?
While hospitalizations and deaths from COVID-19 are increasing again, it's not yet clear whether Delta causes more severe illness than previous strains.
How can we protect unvaccinated children from the Delta variant?
With children 12 and under not yet eligible for the COVID-19 vaccine, kids are especially vulnerable to the Delta variant. One way to protect unvaccinated children is for parents and other close family members to get vaccinated.
It's also a good idea to keep masks handy when going out in public places. Due to risk Delta poses, the American Academy of Pediatrics issued new guidelines July 19 recommending that all staff and students over age 2 wear face masks in school this fall, even if they have been vaccinated.
Parents should also avoid taking their unvaccinated children to crowded, indoor locations and make sure their kids are practicing good hand-washing hygiene. For children younger than 2, limit visits with friends and family members who are unvaccinated or whose vaccination status is unknown and keep up social distancing practices while in public.
While there's no evidence yet that Delta increases disease severity in children, parents should be mindful that in some rare cases, kids can get a severe form of the disease.
"We're seeing more children getting sick and we're seeing some of them get very sick," Surtees said. "Those children can then pass on the virus to other individuals, including people who are immunocompromised or unvaccinated."
Scientists Just Created Liquid Solar Power That Can Be Stored for 18 Years
A team of Swedish scientists has gathered solar power so pure, that until recently, capturing it was an impossibility.
Look no further than this week's climate strikes for evidence that millions of people are passionate about curbing global warming.
Unlike relatively limited solar panel energy storage, norbornadiene can potentially maintain its potency for years.
But even potential solutions, like alternative meats, have their own challenges. Some scientists are putting their focus on the sun to help balance out our energy consumption.
In fact, they are gathering solar power so pure that, until recently, capturing it was an impossibility.
The Lowdown
A group of Swedish scientists has created a liquid called norbornadiene. This liquid sunshine can capture up to 30 percent of raw solar power. To put it in perspective, the best publicly available solar panels can harness 21 percent. Norbornadiene would bring in about 50 percent more power – a significant difference in energy efficiency.
Most notably, unlike relatively limited solar panel energy storage, norbornadiene can potentially maintain its potency for years. We could have the ability to collect and store premium solar power, making it easier for current and future generations to use fossil and nuclear fuel alternatives.
"The norbornadiene molecules that we have made have very good properties, in terms of solar energy capture efficiency, storage time and energy density," says team lead Dr. Kasper Moth-Poulson of the Chamlers University of Technology. "They can store energy without the need for insulation materials for 18 or more years."
Next Up
Swedish scientist Moth-Poulsen and his team have been testing the norbornadiene on the physics building roof at the Chalmers University of Technology. Once activated, it heats up to just below boiling and provides enough power to be useful.
The energy density is 250 watt-hours per kilogram, twice the strength of Tesla's popular Powerall battery.
It requires potentially toxic solvents, like a cobalt-based activator, to transform into its full potential. The team is currently trying to find less-hazardous catalysts to help transform the norbornadiene to its active form, quadricyclane. Exposing it to sunlight is the main way to reactivate the norbornadiene's power. Over time, scientists will likely make it more efficient with less toxic agents.
The energy density is 250 watt-hours per kilogram, twice the strength of Tesla's popular Powerall battery.
Open Questions
The biggest question is safety, perceived or otherwise: Are you ready to drive around with 250 kWh of pure solar in your Hyundai? Norbornadiene may be stable in a hermetically sealed lab, but sculpting it for everyday use requires another level of security.
The half-life of the sunshine power is also an estimate, too. The challenge with new scientific substances is you don't know how the matter will evolve over time. It is easy to be overly optimistic about this one discovery being the key to our energy needs. For the time being, it is wiser to look at norbornadiene as a progressive step rather than a revolutionary one.
Even at its least effective, norbornadiene and its related material is a step toward us utilizing the one natural resource that won't run out for generations. In the short-term, a stable form of it could offset our fossil and nuclear fuel use and even help lower the carbon footprint made by long-distance transportation. It will be fascinating to see what future aircraft builders, home designers and even car manufacturers do as the solar technology conversation heats up.
Moth-Poulsen wants norbornadiene to be a definitive part of the climate change puzzle.
"I hope that in five years, we will see the first products based on our molecules and could help mitigate the daily variations in temperature," he says. "This will lead to increased thermal comfort and reduced energy consumption for heating and cooling."
Virtual Reality is Making Medical Care for Kids Less Scary and Painful
A patient at Children's Hospital Los Angeles (Courtesy of Children's Hospital Los Angeles) plus Bear Blast, developed by AppliedVR.
A blood draw is not normally a fun experience, but these days, virtual reality technology is changing that.
Instead of watching a needle go into his arm, a child wearing a VR headset at Children's Hospital Los Angeles can play a game throwing balls at cartoon bears. In Seattle, at the University of Washington, a burn patient can immerse herself in a soothing snow scene. And at the University of Miami Hospital, a five-minute skin biopsy can become an exciting ride at an amusement park.
VR is transforming once-frightening medical encounters for kids, from blood draws to biopsies to pre-surgical prep, into tolerable ones.
It's literally a game changer, says pediatric neurosurgeon Kurtis Auguste, who uses the tool to help explain pending operations to his young patients and their families. The virtual reality 3-D portrait of their brain is recreated from an MRI, originally to help plan the surgery. The image of normally bland tissue is painted with false colors to better see the boundaries and anomalies of each component. It can be rotated, viewed from every possible angle, zoomed in and out; incisions can be made and likely results anticipated. Auguste has extended its use to patients and families.
"The moment you put these headsets on the kids, we immediately have a link, because honestly, this is how they communicate with each other," says Auguste. "We're all sitting around the table playing games. It's really bridged the distance between me, the pediatric specialist, and my patients" at the Benioff Children's Hospital Oakland, now affiliated with the University of California San Francisco School of Medicine.
The VR experience engages people where they are, immersing them in the environment rather than lecturing them. And it seems to work in all environments, across age and cultural differences, leading to a better grasp of what will be undertaken. That understanding is crucial to meaningful informed consent for surgery. It is particularly relevant for safety-net hospitals, which includes most children's hospitals, because often members of the families were born elsewhere and may have limited understanding of English, not to mention advanced medicine.
Targeting pain
"We're trying to target ways that we can decrease pain, anxiety, fear – what people usually experience as a function of a needle," says Jeffrey Gold, a pioneer in adapting VR at Children's Hospital Los Angeles. He ran the pain clinic there and in 2004 initially focused on phlebotomy, simple blood draws. Many of their kids require frequent blood draws to monitor serious chronic conditions such as diabetes, HIV infection, sickle cell disease, and other conditions that affect the heart, liver, kidneys and other organs.
The scientific explanation of how VR works for pain relief draws upon two basic principles of brain function. The first is "top down inhibition," Gold explains. "We all have the inherent capacity to turn down signals once we determine that signal is no longer harmful, dangerous, hurtful, etc. That's how our brain operates on purpose. It's not just a distraction, it's actually your brain stopping the pain signal at the spinal cord before it can fire all the way up to the frontal lobe."
Second is the analgesic effect from endorphins. "If you're in a gaming environment, and you're having fun and you're laughing and giggling, you are actually releasing endorphins...a neurochemical reaction at the synaptic level of the brain," he says.
Part of what makes VR effective is "what's called a cognitive load, where you have to actually learn something and do something," says Gold. He has worked with developers on a game call Bear Blast, which has proven to be effective in a clinical trial for mitigating pain. But he emphasizes, it is not a one-size-fits all; the programs and patients need to be evaluated to understand what works best for each case.
Gold was a bit surprised to find that VR "actually facilitates quicker blood draws," because the staff doesn't have to manage the kids' anxiety, so "they require fewer needle sticks." The kids, parents, and staff were all having a good time, "and that's a big win when everybody is benefiting." About two years ago the hospital made VR an option that patients can request in the phlebotomy lab, and about half of kids age 4 and older choose to do so.
The technology "gets the kids engaged and performing the activity the way we want them to" to maximize recovery.
VR reduces or eliminates the need to use sedation or anesthesia, which carries a small but real risk of an adverse reaction. And important to parents, it eliminates the recovery time from using sedation, which shortens the visit and time missed from school and work.
A more intriguing question is whether reducing fear and anxiety in early-life experiences with the healthcare system through activities like VR will have a long-term affect on kids' attitudes toward medicine as they grow older. "If you're a screaming meemie when you come get your blood draw when you're five or seven, you're still that anxious adolescent or adult who is all quivering and sweating and avoiding healthcare," Gold says. "That's a longitudinal health outcome I'd love to get my hands on in 10-15 years from now."
Broader applications
Dermatologist Hadar Lev-Tov read about the use of VR to treat pain and decided to try it in his practice at the University of Miami Hospital. He thought, "OK, this is low risk, it's easy to do. So we got some equipment and got it done." It was so affordable he paid for it out of his own pocket, rather than wait to go through administrative channels. The results were so interesting that he decided to publish it as a series of case studies with a wide variety of patients and types of procedures.
Some of them, such as freezing off warts, are not particularly painful. "But there can be a lot of anxiety, especially for kids, which can be worse than pain and can disrupt the procedure." It can trigger a non-rational, primal fight or flight response in the limbic region of the brain.
Adults understand the need for a biopsy of a skin growth and tolerate what might be a momentary flick of pain. "But for a kid you think twice about a biopsy, both because it's a hassle and because it could be a traumatic event for a child," says Lev-Tov. VR has helped to allay such fears and improve medical care.
Integrating VR into practice has been relatively easy, primarily focusing on simple training for staff and ensuring that standard infection control practices are used in handling equipment that is used by different patients. More mundane issues are ensuring that the play back and wi-fi equipment are functioning properly. He has had a few complaints from kids when the procedure is competed and the VR is turned off prematurely, which is why he favors programs like a roller coaster ride that lasts about five minutes, ample time to take a biopsy or two.
The future is today
The pediatric neurosurgeon Auguste is collaborating with colleagues at Oakland Children's to expand use of VR into different areas of care. Cancer specialists often use a port, a bubble installed under the skin in the chest of the child, to administer chemotherapy. But the young patient's curiosity often draws their attention downward to the port and their chin can potentially contaminate or obstruct it, interfering with the procedure. So the team developed a VR game involving birds that requires players to move their heads upward, away from the port, improving administration of the drugs and reducing the risk of infection.
Innovative use of VR just may be one tool that actually makes kids eager to visit the doctor.
Other games are being developed for rehabilitation that require the use of specific nerve and muscle combinations. The technology "gets the kids engaged and performing the activity the way we want them to" to maximize recovery, Auguste explains. "We can monitor their progress by the score on the game, and if it plateaus, maybe switch to another game."
Another project is trying to ease the anxiety and confusion of the patient and family experience within the hospital itself. Hospital staff are creating a personalized VR introductory walking tour that leads from the parking garage through the maze of structures and corridors in the hospital complex to Dr. Auguste's office, phlebotomy, the MRI site, and other locations they might visit. The goal is to make them familiar with key landmarks before they even set foot in the facility. "So when they come the day of the visit they have already taken that exact same path, hopefully more than once."
"They don't miss their MRI appointment and therefore they don't miss their clinical appointment with me," says Auguste. It reduces patient anxiety about the encounter and from the hospital's perspective, it will reduce costs of missed and rescheduled visits simply because patients did not go to the right place at the right time.
The VR visit will be emailed to patients ahead of time and they can watch it on a smartphone installed in a disposable cardboard viewer. Oakland Children's hopes to have the system in place by early next year. Auguste says their goal in using VR, like other health care providers across the country, is "to streamline the entire patient experience."
Innovative use of VR just may be one tool that actually makes kids eager to visit the doctor. That would be a boon to kids, parents, and the health of America.