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."
Meet the Psychologist Using Psychedelics to Treat Racial Trauma
Monnica Williams was stuck. The veteran psychologist wanted to conduct a study using psychedelics, but her university told her they didn't have the expertise to evaluate it via an institutional review board, which is responsible for providing ethical and regulatory oversight for research that involves human participants. Instead, they directed her to a hospital, whose reviewers turned it down, citing research of a banned substance as unethical.
"I said, 'We're not using illegal psilocybin, we're going through Health Canada,'" Williams said. Psilocybin was banned in Canada in 1974, but can now be obtained with an exemption from Health Canada, the federal government's health policy department. After learning this, the hospital review board told Williams they couldn't review her proposal because she's not affiliated with the hospital, after all.
It's all part of balancing bureaucracy with research goals for Williams, a leading expert on racial trauma and psychedelic medicine, as well as obsessive compulsive disorder (OCD), at the University of Ottawa. She's exploring the use of hallucinogenic substances like MDMA and psilocybin — commonly known as ecstasy and magic mushrooms, respectively — to help people of color address the psychological impacts of systemic racism. A prolific researcher, Williams also works as an expert witness, offering clinical evaluations for racial trauma cases.
Scientists have long known that psychedelics produce an altered state of consciousness and openness to new perspectives. For people with mental health conditions who haven't benefited from traditional therapy, psychedelics may be able to help them discover what's causing their pain or trauma, including racial trauma—the mental and emotional injury spurred by racial bias.
"Using psychedelics can not only bring these pain points to the surface for healing, but can reduce the anxiety or response to these memories and allow them to speak openly about them without the pain they bring," Williams says. Her research harnesses the potential of psychedelics to increase neuroplasticity, which includes the brain's ability to build new pathways.
"People of color are dealing with racism all the time, in large and small ways, and even dealing with racism in healthcare, even dealing with racism in therapy."
But she says therapists of color aren't automatically equipped to treat racial trauma. First, she notes, people of color are "vastly underrepresented in the mental health workforce." This is doubly true in psychedelic-assisted psychotherapy, in which a person is guided through a psychedelic session by a therapist or team of therapists, then processes the experience in subsequent therapy sessions.
"On top of that, the therapists of color are getting the same training that the white therapists are getting, so it's not even really guaranteed that they're going to be any better at helping a person that may have racial trauma emerging as part of their experience," she says.
In her own training to become a clinical psychologist at the University of Virginia, Williams says she was taught "how to be a great psychologist for white people." Yet even people of color, she argues, need specialized training to work with marginalized groups, particularly when it comes to MDMA, psilocybin and other psychedelics. Because these drugs can lower natural psychological defense mechanisms, Williams says, it's important for providers to be specially trained.
"People of color are dealing with racism all the time, in large and small ways, and even dealing with racism in healthcare, even dealing with racism in therapy. So [they] generally develop a lot of defenses and coping strategies to ward off racism so that they can function." she says. This is particularly true with psychedelic-assisted psychotherapy: "One possibility is that you're going to be stripped of your defenses, you're going to be vulnerable. And so you have to work with a therapist who is going to understand that and not enact more racism in their work with you."
Williams has struggled to find funding and institutional approval for research involving psychedelics, or funding for investigations into racial trauma or the impacts of conditions like OCD and post-traumatic stress disorder (PTSD) in people of color. With the bulk of her work focusing on OCD, she hoped to focus on people of color, but found there was little funding for that type of research. In 2020, that started to change as structural racism garnered more media attention.
After the killing of George Floyd, a 46-year-old Black man, by a white police officer in May 2020, Williams was flooded with media requests. "Usually, when something like that happens, I get contacted a lot for a couple of weeks, and it dies off. But after George Floyd, it just never did."
Monnica Williams, clinical psychologist at the University of Ottawa
Williams was no stranger to the questions that soon blazed across headlines: How can we mitigate microaggressions? How do race and ethnicity impact mental health? What terms should we use to discuss racial issues? What constitutes an ally, and why aren't there more of them? Why aren't there more people of color in academia, and so many other fields?
Now, she's hoping that the increased attention on racial justice will mean more acceptance for the kind of research she's doing.
In fact, Williams herself has used psychedelics in order to gain a better understanding of how to use them to treat racial trauma. In a study published in January, she and two other Black female psychotherapists took MDMA in a supervised setting, guided by a team of mental health practitioners who helped them process issues that came up as the session progressed. Williams, who was also the study's lead author, found that participants' experiences centered around processing and finding release from racial identities, and, in one case, of simply feeling wholly human without the burden of racial identity for the first time.
The purpose of the study was twofold: to understand how Black women react to psychedelics and to provide safe, firsthand, psychedelic experiences to Black mental health practitioners. One of the other study participants has since gone on to offer psychedelic-assisted psychotherapy to her own patients.
Psychedelic research, and psilocybin in particular, has become a hot topic of late, particularly after Oregon became the first state to legalize it for therapeutic use last November. A survey-based, observational study with 313 participants, published in 2020, paved the way for Williams' more recent MDMA experiments by describing improvements in depression, anxiety and racial trauma among people of color who had used LSD, psilocybin or MDMA in a non-research setting.
Williams and her team included only respondents who reported a moderate to strong psychoactive effect of past psychedelic consumption and believed these experiences provided "relief from the challenging effects of ethnic discrimination." Participants reported a memorable psychedelic experience as well as its acute and lasting effects, completing assessments of psychological insight, mystical experience and emotional challenges experienced during psychedelic experience, then describing their mental health — including depression, anxiety and trauma symptoms — before and after that experience.
Still, Williams says addressing racism is much more complex than treating racial trauma. "One of the questions I get asked a lot is, 'How can Black people cope with racism?' And I don't really like that question," she says. "I think it's important and I don't mind answering it, but I think the more important question is, how can we end racism? What can Black people do to stop racism that's happening to them and what can we do as a society to stop racism? And people aren't really asking this question."
Tiny, Injectable Robots Could Be the Future of Brain Treatments
In the 1966 movie "Fantastic Voyage," actress Raquel Welch and her submarine were shrunk to the size of a cell in order to eliminate a blood clot in a scientist's brain. Now, 55 years later, the scenario is becoming closer to reality.
California-based startup Bionaut Labs has developed a nanobot about the size of a grain of rice that's designed to transport medication to the exact location in the body where it's needed. If you think about it, the conventional way to deliver medicine makes little sense: A painkiller affects the entire body instead of just the arm that's hurting, and chemotherapy is flushed through all the veins instead of precisely targeting the tumor.
"Chemotherapy is delivered systemically," Bionaut-founder and CEO Michael Shpigelmacher says. "Often only a small percentage arrives at the location where it is actually needed."
But what if it was possible to send a tiny robot through the body to attack a tumor or deliver a drug at exactly the right location?
Several startups and academic institutes worldwide are working to develop such a solution but Bionaut Labs seems the furthest along in advancing its invention. "You can think of the Bionaut as a tiny screw that moves through the veins as if steered by an invisible screwdriver until it arrives at the tumor," Shpigelmacher explains. Via Zoom, he shares the screen of an X-ray machine in his Culver City lab to demonstrate how the half-transparent, yellowish device winds its way along the spine in the body. The nanobot contains a tiny but powerful magnet. The "invisible screwdriver" is an external magnetic field that rotates that magnet inside the device and gets it to move and change directions.
The current model has a diameter of less than a millimeter. Shpigelmacher's engineers could build the miniature vehicle even smaller but the current size has the advantage of being big enough to see with bare eyes. It can also deliver more medicine than a tinier version. In the Zoom demonstration, the micorobot is injected into the spine, not unlike an epidural, and pulled along the spine through an outside magnet until the Bionaut reaches the brainstem. Depending which organ it needs to reach, it could be inserted elsewhere, for instance through a catheter.
"The hope is that we can develop a vehicle to transport medication deep into the body."
Imagine moving a screw through a steak with a magnet — that's essentially how the device works. But of course, the Bionaut is considerably different from an ordinary screw: "At the right location, we give a magnetic signal, and it unloads its medicine package," Shpigelmacher says.
To start, Bionaut Labs wants to use its device to treat Parkinson's disease and brain stem gliomas, a type of cancer that largely affects children and teenagers. About 300 to 400 young people a year are diagnosed with this type of tumor. Radiation and brain surgery risk damaging sensitive brain tissue, and chemotherapy often doesn't work. Most children with these tumors live less than 18 months. A nanobot delivering targeted chemotherapy could be a gamechanger. "These patients really don't have any other hope," Shpigelmacher says.
Of course, the main challenge of the developing such a device is guaranteeing that it's safe. Because tissue is so sensitive, any mistake could risk disastrous results. Over the past four years, Bionaut has tested its technology in dozens of healthy sheep and pigs with no major adverse effects. Sheep make a good stand-in for humans because their brains and spines are similar to ours.
The Bionaut device is about the size of a grain of rice.
Bionaut Labs
"As the Bionaut moves through brain tissue, it creates a transient track that heals within a few weeks," Shpigelmacher says. The company is hoping to be the first to test a nanobot in humans. That could happen as early as 2023, Shpigelmacher says.
Once the technique has been perfected, further applications could include addressing other kinds of brain disorders that are considered incurable now, such as Alzheimer's or Huntington's disease. "Microrobots could serve as a bridgehead, opening the gateway to the brain and facilitating precise access of deep brain structure – either to deliver medication, take cell samples or stimulate specific brain regions," Shpigelmacher says.
Robot-assisted hybrid surgery with artificial intelligence is already used in state-of-the-art surgery centers, and many medical experts believe that nanorobotics will be the instrument of the future. In 2016, three scientists were awarded the Nobel Prize in Chemistry for their development of "the world's smallest machines," nano "elevators" and minuscule motors. Since then, the scientific experiments have progressed to the point where applicable devices are moving closer to actually being implemented.
Bionaut's technology was initially developed by a research team lead by Peer Fischer, head of the independent Micro Nano and Molecular Systems Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany. Fischer is considered a pioneer in the research of nano systems, which he began at Harvard University more than a decade ago. He and his team are advising Bionaut Labs and have licensed their technology to the company.
"The hope is that we can develop a vehicle to transport medication deep into the body," says Max Planck scientist Tian Qiu, who leads the cooperation with Bionaut Labs. He agrees with Shpigelmacher that the Bionaut's size is perfect for transporting medication loads and is researching potential applications for even smaller nanorobots, especially in the eye, where the tissue is extremely sensitive. "Nanorobots can sneak through very fine tissue without causing damage."
In "Fantastic Voyage," Raquel Welch's adventures inside the body of a dissident scientist let her swim through his veins into his brain, but her shrunken miniature submarine is attacked by antibodies; she has to flee through the nerves into the scientist's eye where she escapes into freedom on a tear drop. In reality, the exit in the lab is much more mundane. The Bionaut simply leaves the body through the same port where it entered. But apart from the dramatization, the "Fantastic Voyage" was almost prophetic, or, as Shpigelmacher says, "Science fiction becomes science reality."