Posted on by Lawrence Tabak, D.D.S., Ph.D.
While great progress has been made in controlling the COVID-19 pandemic, America’s opioid crisis continues to evolve in unexpected ways. The opioid crisis, which worsened during the pandemic and now involves the scourge of fentanyl, claims more than 70,000 lives each year in the United States . But throughout the pandemic, NIH has continued its research efforts to help people with a substance use disorder find the help that they so need. These efforts include helping to find relief for the millions of Americans who live with severe and chronic pain.
Recently, I traveled to Atlanta for the Rx and Illicit Drug Summit 2022. While there, I moderated an evening fireside chat with two of NIH’s leaders in combating the opioid crisis: Nora Volkow, director of the National Institute on Drug Abuse (NIDA); and Rebecca Baker, director of Helping to End Addiction Long-term® (HEAL) initiative. What follows is an edited, condensed transcript of our conversation.
Tabak: Let’s start with Nora. When did the opioid crisis begin, and how has it changed over the years
Volkow: It started just before the year 2000 with the over-prescription of opioid medications. People were becoming addicted to them, many from diverted product. By 2010, CDC developed guidelines that decreased the over-prescription. But then, we saw a surge in heroin use. That turned the opioid crisis into two problems: prescription opioids and heroin.
In 2016, we encountered the worst scourge yet. It is fentanyl, an opioid that’s 50 times more potent than heroin. Fentanyl is easily manufactured, and it’s easier than other opioids to hide and transport across the border. That makes this drug very profitable.
What we have seen during the pandemic is the expansion of fentanyl use in the United States. Initially, fentanyl made its way to the Northeast; now it’s everywhere. Initially, it was used to contaminate heroin; now it’s used to contaminate cocaine, methamphetamine, and, most recently, illicit prescription drugs, such as benzodiazepines and stimulants. With fentanyl contaminating all these drugs, we’re also seeing a steep rise in mortality from cocaine and methamphetamine use in African Americans, American Indians, and Alaska natives.
Tabak: What about teens? A recent study in the journal JAMA reported for the first time in a decade that overdose deaths among U.S. teens rose dramatically in 2020 and kept rising through 2021 . Is fentanyl behind this alarming increase?
Volkow: Yes, and it has us very concerned. The increase also surprised us. Over the past decade, we have seen a consistent decrease in adolescent drug use. In fact, there are some drugs that have the lowest usage rates that we’ve ever recorded. To observe this more than doubling of overdose deaths from fentanyl before the COVID pandemic was a major surprise.
Adolescents don’t typically use heroin, nor do they seek out fentanyl. Our fear is adolescents are misusing illicit prescriptions contaminated with fentanyl. Because an estimated 30-40 percent of those tainted pills contain levels of fentanyl that can kill you, it becomes a game of Russian roulette. This dangerous game is being played by adolescents who may just be experimenting with illicit pills.
Tabak: For people with substance use disorders, there are new ways to get help. In fact, one of the very few positive outcomes of the pandemic is the emergence of telehealth. If we can learn to navigate the various regulatory issues, do you see a place for telehealth going forward?
Volkow: When you have a crisis like this one, there’s a real need to accelerate interventions and innovation like telehealth. It certainly existed before the pandemic, and we knew that telehealth was beneficial for the treatment of substance use disorders. But it was very difficult to get reimbursement, making access extremely limited.
When COVID overwhelmed emergency departments, people with substance use disorders could no longer get help there. Other interventions were needed, and telehealth helped fill the void. It also had the advantage of reaching rural populations in states such as Kentucky, West Virginia, Ohio, where easy access to treatment or unique interventions can be challenging. In many prisons and jails, administrators worried about bringing web-based technologies into their facilities. So, in partnership with the Justice Department, we have created networks that now will enable the entry of telehealth into jails and prisons.
Tabak: Rebecca, it’s been four years since the HEAL initiative was announced at this very summit in 2018. How is the initiative addressing this ever-evolving crisis?
Baker: We’ve launched over 600 research projects across the country at institutions, hospitals, and research centers in a broad range of scientific areas. We’re working to come up with new treatment options for pain and addiction. There’s exciting research underway to address the craving and sleep disruption caused by opioid withdrawal. This research has led to over 20 investigational new drug applications to the FDA. Some are for repurposed drugs, compounds that have already been shown to be safe and effective for treating other health conditions that may also have value for treating addiction. Some are completely novel. We have also initiated the first testing of an opioid vaccine, for oxycodone, to prevent relapse and overdose in high-risk individuals.
Tabak: What about clinical research?
Baker: We’re testing multiple different treatments for both pain and addiction. Not everyone with pain is the same, and not every treatment is going to work the same for everyone. We’re conducting clinical trials in real-world settings to find out what works best for patients. We’re also working to implement lifesaving, evidence-based interventions into places where people seek help, including faith, community, and criminal justice settings.
Tabak: The pandemic highlighted inequities in our health-care system. These inequities afflict individuals and populations who are struggling with addiction and overdose. Nora, what needs to be done to address the social determinants of racial disparities?
Volkow: This is an extraordinarily important question. As you noted, certain racial and ethnic groups had disproportionately higher mortality rates from COVID. We have seen the same with overdose deaths. For example, we know that the most important intervention for preventing overdoses is to initiate medications such as methadone, buprenorphine or vivitrol. But Black Americans are initiated on these medications at least five years later than white Americans. Similarly, Black Americans also are less likely to receive the overdose-reversal medication naloxone.
That’s not right. We must ask what are the core causes of limited access to high-quality health care? Low income is a major contributing factor. Helping people get an education is one of the most important factors to address it. Another factor is distrust of the medical system. When racial and ethnic discrimination is compounded by discrimination because a person has a substance use disorder, you can see why it becomes very difficult for some to seek help. As a society, we certainly need to address racial discrimination. But we also need to address discrimination against substance use disorders in people of all races who are vulnerable.
Baker: Our research is tackling these barriers head on with a direct focus on stigma. As Nora alluded to, oftentimes providers may not offer lifesaving medication to some patients, and we’ve developed and are testing research training to help providers recognize and address their own biases and behaviors in caring for different populations.
We have supported research on the drivers of equity. A big part of this is engaging with people with lived experience and making sure that the interventions being designed are feasible in the real world. Not everyone has access to health insurance, transportation, childcare—the support that they may need to sustain treatment and recovery. In short, our research is seeking ways to enhance linkage to treatment.
Nora mentioned the importance of telehealth in improving equity. That’s another research focus, as well as developing tailored, culturally appropriate interventions for addressing pain and addiction. When you have this trust issue, you can’t always go in with a prescription or a recommendation from a physician. So in American and Alaskan native communities, we’re integrating evidence-based prevention approaches with traditional practices like wellness gatherings, cooking together, use of sage and spirituality, along with community support, and seeing if that encourages and increases the uptake of these prevention approaches in communities that need it so much.
Tabak: The most heartbreaking impact of the opioid crisis has been the infants born dependent on opioids. Rebecca, what’s being done to help the very youngest victims of the opioid crisis born with neonatal opioid withdrawal syndrome, or NOWS?
Baker: Thanks for asking about the infants. Babies with NOWS undergo withdrawal at birth and cry inconsolably, often with extreme stomach upset and sometimes even with seizures. Our research found that hospitals across the country vary greatly in how they treat these babies. Our program, ACT NOW, or Advancing Clinical Trials in Neonatal Opioid Withdrawal, aims to provide concrete guidance for nurses in the NICU treating these infants. One of the studies that we call Eat, Sleep, Console focuses on the abilities of the baby. Our researchers are testing if the ability to eat, sleep, or be consoled increases bonding with the mother and if it reduces time in the hospital, as well as other long-term health outcomes.
In addition to that NOWS program, we’ve also launched the HEALthy Brain and Child Development Study, or HBCD, that seeks to understand the long-term consequences of opioid exposure together with all the other environmental and other factors the baby experiences as they grow up. The hope is that together these studies will inform future prevention and treatment efforts for both mental health and also substance use and addiction.
Tabak: As the surge in heroin use and appearance of fentanyl has taught us, the opioid crisis has ever-changing dynamics. It tells us that we need better prevention strategies. Rebecca, could you share what HEAL is doing about prevention?
Baker: Prevention has always been a core component of the HEAL Initiative in a number of ways. The first is by preventing unnecessary opioid exposures through enhanced and evidence-based pain management. HEAL is supporting research on new small molecules, new devices, new biologic therapeutics that could treat pain and distinct pain conditions without opioids. And we’re also researching and providing guidance for clinicians on strategies for managing pain without medication, including acupuncture and physical therapy. They can often be just as effective and more sustainable.
HEAL is also working to address risky opioid use outside of pain management, especially in high-risk groups. That includes teens and young adults who may be experimenting, people lacking stable housing, patients who are on high-dose opioids for pain management, or they maybe have gone off high-dose opioids but still have them in their possession.
Finally, to prevent overdose we have to give naloxone to the people who need it. The HEALing Communities Study has taken some really innovative approaches to providing naloxone in libraries, on the beach, and places where overdoses are actually happening, not just in medical settings. And I think that will be, in our fight against the overdose crisis, a key tool.
Volkow: Larry, I’d like to add a few words on prevention. There are evidence-based interventions that have been shown to be quite effective for preventing substance use among teenagers and young adults. And yet, they are not implemented. We have evidence-based interventions that work for prevention. We have evidence-based interventions that work for treatment. But we don’t provide the resources for their implementation, nor do we train the personnel that can carry it over.
Science can give us tools, but if we do not partner at the next level for their implementation, those tools do not have the impact they should have. That’s why I always bring up the importance of policy in the implementation phase.
Tabak: Rebecca, the opioid crisis got started with a lack of good options for treating pain. Could you share with us how HEAL’s research efforts are addressing the needs of millions of Americans who experience both chronic pain and opioid use disorder?
Baker: It’s so important to remember people with pain. We can’t let our efforts to combat the opioid crisis make us lose sight of the needs of the millions of Americans with pain. One hundred million Americans experience pain; half of them have severe pain, daily pain, and 20 million have such severe pain that they can’t do things that are important to them in their life, family, job, other activities that bring their life meaning.
HEAL recognizes that these individuals need better options. New non-addictive pain treatments. But as you say, there is a special need for people with a substance use disorder who also have pain. They desperately need new and better options. And so we recently, through the HEAL Initiative, launched a new trials network that couples medication-based treatment for opioid use disorders, so that’s methadone or buprenorphine, with new pain-management strategies such as psychotherapy or yoga in the opioid use disorder treatment setting so that you’re not sending them around to lots of different places. And our hope is that this integrated approach will address some of the fragmented healthcare challenges that often results in poor care for these patients.
My last point would be that some patients need opioids to function. We can’t forget as we make sure that we are limiting risky opioid use that we don’t take away necessary opioids for these patients, and so our future research will incorporate ways of making sure that they receive needed treatment while also preventing them from the risks of opioid use disorder.
Tabak: Rebecca, let me ask you one more question. What do you want the folks here to remember about HEAL?
Baker: HEAL stands for Helping to End Addiction Long-term, and nobody knows more than the people in this room how challenging and important that really is. We’ve heard a little bit about the great promise of our research and some of the advances that are coming through our research pipeline, new treatments, new guidance for clinicians and caregivers. I want everyone to know that we want to work with you. By working together, I’m confident that we will tailor these new advances to meet the individual needs of the patients and populations that we serve.
Tabak: Nora, what would you like to add?
Volkow: This afternoon, I met with two parents who told me the story of how they lost their daughter to an overdose. They showed me pictures of this fantastic girl, along with her drawings. Whenever we think about overdose deaths in America, the sheer number—75,000—can make us indifferent. But when you can focus on one person and feel the love surrounding that life, you remember the value of this work.
Like in COVID, substance use disorders are a painful problem that we’re all experiencing in some way. They may have upset our lives. But they may have brought us together and, in many instances, brought out the best that humans can do. The best, to me, is caring for one another and taking the responsibility of helping those that are most vulnerable. I believe that science has a purpose. And here we have a purpose: to use science to bring solutions that can prevent and treat those suffering from substance use disorders.
Tabak: Thanks to both of you for this enlightening conversation.
 Drug overdose deaths, Centers for Disease Control and Prevention, February 22, 2022.
 Trends in drug overdose deaths among US adolescents, January 2010 to June 2021. Friedman J. et al. JAMA. 2022 Apr 12;327(14):1398-1400.
Video: Evening Plenary with NIH’s Lawrence Tabak, Nora Volkow, and Rebecca Baker (Rx and Illicit Drug Summit 2022)
SAMHSA’s National Helpline (Substance Abuse and Mental Health Services Administration, Rockville, MD)
Opioids (National Institute on Drug Abuse/NIH)
Rebecca Baker (HEAL/NIH)
Nora Volkow (NIDA)
As COVID-19 rapidly expanded throughout the world in April 2020, many in the biomedical technology community voiced significant concerns about the lack of available diagnostic tests. At that time, testing for SARS-CoV-2, the coronavirus that causes COVID-19, was conducted exclusively in clinical laboratories by order of a health-care provider. “Over the counter” (OTC) tests did not exist, and low complexity point of care (POC) platforms were rare. Fewer than 8 million tests were performed in the U.S. that month, and it was clear that we needed a radical transformation to make tests faster and more accessible.
By February 2022, driven by the Omicron variant surge, U.S. capacity had increased to a new record of more than 1.2 billion tests in a single month. Remarkably, the overwhelming majority of these—more than 85 percent—were “rapid tests” conducted in home and POC settings.
The story behind this practice-changing, “test-at-home” transformation is deeply rooted in technologic and manufacturing innovation. The NIH’s National Institute of Biomedical Imaging and Bioengineering (NIBIB), working collaboratively with multiple partners across NIH, government, academia, and the private sector, has been privileged to play a leading role in this effort via the Rapid Acceleration of Diagnostics (RADx®) initiative. On this two-year anniversary of RADx, we take a brief look back at its formation, impact, and potential for future growth.
On April 24, 2020, Congress recognized that testing was an urgent national need and appropriated $1.5 billion to NIH via an emergency supplement . The goal was to substantially increase the number, type, and availability of diagnostic tests in only five to six months. Since the “normal” commercialization cycle for this type of diagnostic technology is typically more than five years, we needed an entirely new approach . . . fast.
The RADx initiative was launched just five days after that challenging Congressional directive . Four NIH RADx programs were eventually created to support technology development and delivery, with the goal of matching test performance with community needs .The first two programs, RADx Tech and RADx Advanced Technology Platforms (ATP), were developed by NIBIB and focused on innovation for rapidly creating, scaling up, and deploying new technologies.
RADx Tech is built around NIBIB’s Point of Care Technologies Research Network (POCTRN) and includes core activities for technology review, test validation, clinical studies, regulatory authorization, and test deployment. Overall, the RADx Tech network includes approximately 900 participants from government, academia, and the private sector with unique capabilities and resources designed to decrease inherent risk and guide technologies from design and development to fully disseminated commercial products.
At the core of RADx Tech operations is the “innovation funnel” rapid review process, popularized as a shark tank . A total of 824 complete applications were submitted during two open calls in a four-month period, beginning April 2020 and during a one-month period in June 2021. Forty-seven projects received phase 1 funding to validate and lower the inherent risk of developing these technologies. Meanwhile, 50 companies received phase 2 contracts to support FDA authorization studies and manufacturing expansion 
Beyond test development, RADx Tech has evolved to become a key contributor to the U.S. COVID-19 response. The RADx Independent Test Assessment Program (ITAP) was launched in October 2021 to accelerate regulatory authorization of new tests as a joint effort with the Food and Drug Administration (FDA) . The ITAP acquires analytical and clinical performance data and works closely with FDA and manufacturers to shave weeks to months off the time it normally takes to receive Emergency Use Authorization (EUA).
The RADx Tech program also created a Variant Task Force to monitor the performance of tests against each new coronavirus “variant of concern” that emerges. This helps to ensure that marketed tests continue to remain effective. Other innovative RADx Tech projects include Say Yes! Covid Test, the first online free OTC test distribution program, and Project Rosa, which conducts real-time variant tracking across the country .
RADx Tech, by any measure, has exceeded even the most-optimistic expectations. In two years, RADx Tech-supported companies have received 44 EUAs and added approximately 2 billion tests and test products to the U.S. capacity. These remarkable numbers have steadily increased from more than16 million tests in September 2020, just five months after the program was established .
RADx Tech has also made significant contributions to the distribution of 1 billion free OTC tests via the government site, COVID.gov/tests. It has also provided critical guidance on serial testing and variants that have improved test performance and changed regulatory practice [9,10]. In addition, the RADx Mobile Application Reporting System (RADx MARS) reduces barriers to test reporting and test-to-treat strategies’ The latter offers immediate treatment options via telehealth or a POC location whenever a positive test result is reported. Finally, the When to Test website provides critical guidance on when and how to test for individuals, groups, and communities.
As we look to the future, RADx Tech has enormous potential to impact the U.S. response to other pathogens, diseases, and future pandemics. Major challenges going forward include improving home tests to work as well as lab platforms and building digital health networks for capturing and reporting test results to public health officials .
A recent editorial published in the journal Nature Biotechnology noted, “RADx has spawned a phalanx of diagnostic products to market in just 12 months. Its long-term impact on point of care, at-home, and population testing may be even more profound .” We are now poised to advance a new wave of precision medicine that’s led by innovative diagnostic technologies. It represents a unique opportunity to emerge stronger from the pandemic and achieve long-term impact.
 NIH mobilizes national innovation initiative for COVID-19 diagnostics, NIH news release, April 29, 2020.
 Rapid scaling up of Covid-19 diagnostic testing in the United States—The NIH RADx Initiative. Tromberg BJ, Schwetz TA, Pérez-Stable EJ, Hodes RJ, Woychik RP, Bright RA, Fleurence RL, Collins FS. N Engl J Med. 2020 Sep 10;383(11):1071-1077.
 We need more covid-19 tests. We propose a ‘shark tank’ to get us there. Alexander L. and Blunt R., Washington Post, April 20, 2020.
 RADx® Tech/ATP dashboard, National Institute of Biomedical Imaging and Bioengineering, NIH.
 New HHS actions add to Biden Administration efforts to increase access to easy-to-use over-the-counter COVID-19 tests. U.S. Department of Health and Human Services Press Office, October 25, 2021.
 A method for variant agnostic detection of SARS-CoV-2, rapid monitoring of circulating variants, detection of mutations of biological significance, and early detection of emergent variants such as Omicron. Lai E, et al. medRxiV preprint, January 9, 2022.
 Longitudinal assessment of diagnostic test performance over the course of acute SARS-CoV-2 infection. Smith RL, et al. J Infect Dis. 2021 Sep 17;224(6):976-982.
 Comparison of rapid antigen tests’ performance between Delta (B.1.61.7; AY.X) and Omicron (B.1.1.529; BA1) variants of SARS-CoV-2: Secondary analysis from a serial home self-testing study. Soni A, et al. MedRxiv preprint, March 2, 2022.
 Reporting COVID-19 self-test results: The next frontier. Health Affairs, Juluru K., et al. Health Affairs, February 11, 2022.
 Radical solutions. Nat Biotechnol. 2021 Apr;39(4):391.
Get Free At-Home COVID Tests (COVID.gov)
When to Test (Consortia for Improving Medicine with Innovation & Technology, Boston)
RADx Programs (NIH)
RADx® Tech and ATP Programs (National Institute of Biomedical Imaging and Biomedical Engineering/NIH)
[Note: Acting NIH Director Lawrence Tabak has asked the heads of NIH’s Institutes and Centers (ICs) to contribute occasional guest posts to the blog to highlight some of the interesting science that they support and conduct. This is the eighth in the series of NIH IC guest posts that will run until a new permanent NIH director is in place.]
Although COVID-19 has dominated our attention for the past two years, tuberculosis (TB), an ancient scourge, remains a dominating infectious disease globally, with an estimated 10 million new cases and more than 1.3 million deaths in 2020. TB disproportionately afflicts the poor and has long been the leading cause of death in people living with HIV.
Unfortunately, during the global COVID-19 pandemic, recent gains in TB control have been stalled or reversed. We’ve seen a massive drop in new TB diagnoses, reflecting poor access to care and an uptick in deaths in 2020 .
We are fighting TB with an armory of old weapons inferior to those we have for COVID-19. The Bacillus Calmette–Guérin (BCG) vaccine, the world’s only licensed TB vaccine, has been in use for more than 100 years. While BCG is somewhat effective at preventing TB meningitis in children, it provides more limited durable protection against pulmonary TB in children and adults. More effective vaccination strategies to prevent infection and disease, decrease relapse rates, and shorten durations of treatment are desperately needed to reduce the terrible global burden of TB.
In this regard, over the past five years, several exciting research advances have generated new optimism in the field of TB vaccinology. Non-human primate studies conducted at my National Institute of Allergy and Infectious Diseases’ (NIAID) Vaccine Research Center and other NIAID-funded laboratories have demonstrated that effective immunity against infection is achievable and that administering BCG intravenously, rather than under the skin as it currently is given, is highly protective .
Results from a phase 2 trial testing BCG revaccination in adolescents at high risk of TB infection suggested this approach could help prevent TB . In addition, a phase 2 trial of an experimental TB vaccine based on the recombinant protein M72 and an immune-priming adjuvant, AS01, also showed promise in preventing active TB disease in latently infected adults .
Both candidates are now moving on to phase 3 efficacy trials. The encouraging results of these trials, combined with nine other candidates currently in phase 2 or 3 studies , offer new hope that improved vaccines may be on the horizon. The NIAID is working with a team of other funders and investigators to analyze the correlates of protection from these studies to inform future TB vaccine development.
Even with these exciting developments, it is critical to accelerate our efforts to enhance and diversify the TB vaccine pipeline by addressing persistent basic and translational research gaps. To this end, NIAID has several new programs. The Immune Protection Against Mtb Centers are taking a multidisciplinary approach to integrate animal and human data to gain a comprehensive understanding of the immune responses required to prevent TB infection and disease.
This spring, NIAID will fund awards under the Innovation for TB Vaccine Discovery program that will focus on the discovery and early evaluation of novel TB vaccine candidates with the goal of diversifying the TB vaccine pipeline. Later this year, the Advancing Vaccine Adjuvant Research for TB program will systematically assess combinations of TB immunogens and adjuvants. Finally, NIAID’s well-established clinical trials networks are planning two new clinical trials of TB vaccine candidates.
As we look to the future, we must apply the lessons learned in the development of the COVID-19 vaccines to longstanding public health challenges such as TB. COVID-19 vaccine development was hugely successful due to the use of novel vaccine platforms, structure-based vaccine design, community engagement for rapid clinical trial enrollment, real-time data sharing with key stakeholders, and innovative trial designs.
However, critical gaps remain in our armamentarium. These include the harnessing the immunology of the tissues that line the respiratory tract to design vaccines more adept at blocking initial infection and transmission, employing thermostable formulations and novel delivery systems for resource-limited settings, and crafting effective messaging around vaccines for different populations.
As we work to develop better ways to prevent, diagnose, and treat TB, we will do well to remember the great public health icon, Paul Farmer, who tragically passed away earlier this year at a much too young age. Paul witnessed firsthand the devastating consequences of TB and its drug resistant forms in Haiti, Peru, and other parts of the world.
In addition to leading efforts to improve how TB is treated, Paul provided direct patient care in underserved communities and demanded that the world do more to meet their needs. As we honor Paul’s legacy, let us accelerate our efforts to find better tools to fight TB and other diseases of global health importance that exact a disproportionate toll among the poor and underserved.
 Global tuberculosis report 2021. WHO. October 14, 2021.
 Prevention of tuberculosis in macaques after intravenous BCG immunization. Darrah PA, Zeppa JJ, Maiello P, Hackney JA, Wadsworth MH,. Hughes TK, Pokkali S, Swanson PA, Grant NL, Rodgers MA, Kamath M, Causgrove CM, Laddy DJ, Bonavia A, Casimiro D, Lin PL, Klein E, White AG, Scanga CA, Shalek AK, Roederer M, Flynn JL, and Seder RA. Nature. 2020 Jan 1; 577: 95–102.
 Prevention of M. tuberculosis Infection with H4:IC31 vaccine or BCG revaccination. Nemes E, Geldenhuys H, Rozot V, Rutkowski KT, Ratangee F,Bilek N., Mabwe S, Makhethe L, Erasmus M, Toefy A, Mulenga H, Hanekom WA, et al. N Engl J Med 2018; 379:138-149.
 Final analysis of a trial of M72/AS01E vaccine to prevent tuberculosis. Tait DR, Hatherill M, Van Der Meeren O, Ginsberg AM, Van Brakel E, Salaun B, Scriba TJ, Akite EJ, Ayles HM, et al.
 Pipeline Report 2021: Tuberculosis Vaccines. TAG. October 2021.
Tuberculosis (National Institute of Allergy and Infectious Diseases/NIH)
Partners in Health (Boston, MA)
[Note: Acting NIH Director Lawrence Tabak has asked the heads of NIH’s Institutes and Centers (ICs) to contribute occasional guest posts to the blog to highlight some of the interesting science that they support and conduct. This is the seventh in the series of NIH IC guest posts that will run until a new permanent NIH director is in place.]
Human skin is home to diverse ecosystems including bacteria, viruses, and fungi. These microbial communities comprise hundreds of species and are collectively known as the skin microbiome. The skin microbiome is thought to play a vital role in fending off disease-causing microorganisms (pathogens), boosting barrier protection, and aiding immune defenses.
Maintaining a balanced skin microbiome involves a complex and dynamic interplay among microorganisms, immune cells, skin cells, and other factors. In general, bacteria far outnumber viral, fungal, or other microbial species on the skin. Bacterial communities, which are strongly influenced by conditions such as skin moisture, temperature, and pH, vary widely across the body. For example, facial cheek skin hosts mostly Cutibacterium along with a bit of the skin fungus Malassezia. The heel is colonized by different types of bacteria including Staphylococcus and Corynebacteria.
In some diseases, such as acne and eczema, the skin microbiome is altered. Typically, this means an increase in pathogenic microorganisms and a decrease in beneficial ones. An altered skin microbiome can also be associated with inflammation, severe disease symptoms, and changes in the human immune system.
Heidi H. Kong is working to understand the role of the skin microbiome in health and disease. She is a senior investigator in the Intramural Research Program at NIH’s National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) and an adjunct investigator at NIH’s National Cancer Institute (NCI).
More than a decade ago, Kong and Julie A. Segre, an intramural researcher at NIH’s National Human Genome Research Institute, analyzed the microbial makeup of healthy individuals. Kong swabbed the skin of these healthy volunteers in 20 different sites, from the forehead to the toenail. The study revealed that the surface of the human body provides various environmental niches, depending on whether the skin is moist, dry, or sebaceous (oily). Different bacterial species predominate in each niche. Kong and Segre were particularly interested in body areas that have predilections for disease. For example, psoriasis is often found on the outside of elbows and knees, and the back of the scalp.
Earlier this year, Kong and Segre published another broad analysis of the human skin microbiome  in collaboration with scientists at the European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), United Kingdom. This new catalog, called the Skin Microbial Genome Collection, is thought to identify about 85 percent of the microorganisms present on healthy skin from 19 body sites. It documents more than 600 bacterial species—including 174 that were discovered during the study—as well as more than 6,900 viruses and some fungi, including three newly discovered species.
Kong’s work has provided compelling evidence that the human immune system plays a role in shaping the skin microbiome. In 2018, she, Segre, and colleagues from the intramural programs of NCI and NIH’s National Institute of Allergy and Infectious Diseases analyzed skin from eight different sites on 27 people with a rare primary immunodeficiency disease known as DOCK8 deficiency .
People with the condition have recurrent infections in the skin, sinuses, and airways, and are susceptible to different cancers. Kong and colleagues found that the skin of people with DOCK8 deficiency contains significantly more DNA viruses (90 percent of the skin microbiome on average) than people without the condition (6 or 7 percent of the skin microbiome).
Other researchers are hoping to leverage features of the microbiome to develop targeted therapies for skin diseases. Richard L. Gallo, a NIAMS grantee at the University of California, San Diego, is currently focused on acne and eczema (also called atopic dermatitis). Acne is associated with certain strains of Cutibacterium acnes (C. acnes, formerly called Propionibacterium acnes or P. acnes). Eczema is often associated with Staphylococcus aureus (S. aureus).
Severe cases of acne and eczema are commonly treated with broad-spectrum antibiotics, which wipe out most of the bacteria, including beneficial species. The goal of microbiome-targeted therapy is to kill only the disease-associated bacteria and avoid increasing the risk that some strains will develop antibiotic resistance.
In 2020, Gallo and colleagues identified a strain of Staphylococcus capitis from healthy human skin (S. capitis E12) that selectively inhibits the growth of C. acnes without negatively impacting other bacteria or human skin cells . S. capitis E12 produces four different toxins that act together to target C. acnes. The research team created an extract of the four toxins and tested it using animal models. In most cases, the extract was more potent at killing C. acnes—including acne-associated strains—than several commonly prescribed antibiotics (erythromycin, tetracycline, and clindamycin). And, unlike antibiotics, the extract does not appear to promote drug-resistance, at least for the 20 generations observed by the researchers.
Eczema is a chronic, relapsing disease characterized by skin that is dry, itchy, inflamed, and prone to infection, including by pathogens such as S. aureus and herpes virus. Although the cause of eczema is unknown, the condition is associated with human genetic mutations, disruption of the skin’s barrier, inflammation-triggering allergens, and imbalances in the skin microbiome.
In 2017, Gallo’s research team discovered that, in healthy human skin, certain strains of Staphylococcus hominis and Staphylococcus epidermis produce potent antimicrobial molecules known as lantibiotics . These beneficial strains are far less common on the skin of people with eczema. The lantibiotics work synergistically with LL-37, an antimicrobial molecule produced by the human immune system, to selectively kill S. aureus, including methicillin-resistant strains (MRSA).
Gallo and his colleagues then examined the safety and therapeutic potential of these beneficial strains isolated from the human skin microbiome. In animal tests, strains of S. hominis and S. epidermis that produce lantibiotics killed S. aureus and blocked production of its toxin.
Gallo’s group has now expanded their work to early studies in humans. In 2021, two independent phase 1 clinical trials [5,6] conducted by Gallo and his colleagues investigated the effects of these strains on people with eczema. These double-blind, placebo-controlled trials involved one-week of topical application of beneficial bacteria to the forearm of adults with S. aureus-positive eczema. The results demonstrated that the treatment was safe, showed a significant decrease in S. aureus, and improved eczema symptoms in most patients. This is encouraging news for those hoping to develop microbiome-targeted therapy for inflammatory skin diseases.
As research on the skin microbiome advances on different fronts, it will provide deeper insight into the multi-faceted microbial communities that are so critical to health and disease. One day, we may even be able to harness the microbiome as a source of therapeutics to alleviate inflammation, promote wound healing, or suppress certain skin cancers.
 Integrating cultivation and metagenomics for a multi-kingdom view of skin microbiome diversity and functions. Saheb Kashaf S, Proctor DM, Deming C, Saary P, Hölzer M; NISC Comparative Sequencing Program, Taylor ME, Kong HH, Segre JA, Almeida A, Finn RD. Nat Microbiol. 2022 Jan;7(1):169-179.
 Expanded skin virome in DOCK8-deficient patients. Tirosh O, Conlan S, Deming C, Lee-Lin SQ, Huang X; NISC Comparative Sequencing Program, Su HC, Freeman AF, Segre JA, Kong HH. Nat Med. 2018 Dec;24(12):1815-1821.
 Identification of a human skin commensal bacterium that selectively kills Cutibacterium acnes. O’Neill AM, Nakatsuji T, Hayachi A, Williams MR, Mills RH, Gonzalez DJ, Gallo RL. J Invest Dermatol. 2020 Aug;140(8):1619-1628.e2.
 Antimicrobials from human skin commensal bacteria protect against Staphylococcus aureus and are deficient in atopic dermatitis. Nakatsuji T, Chen TH, Narala S, Chun KA, Two AM, Yun T, Shafiq F, Kotol PF, Bouslimani A, Melnik AV, Latif H, Kim JN, Lockhart A, Artis K, David G, Taylor P, Streib J, Dorrestein PC, Grier A, Gill SR, Zengler K, Hata TR, Leung DY, Gallo RL. Sci Transl Med. 2017 Feb 22;9(378):eaah4680.
 Development of a human skin commensal microbe for bacteriotherapy of atopic dermatitis and use in a phase 1 randomized clinical trial. Nakatsuji T, Hata TR, Tong Y, Cheng JY, Shafiq F, Butcher AM, Salem SS, Brinton SL, Rudman Spergel AK, Johnson K, Jepson B, Calatroni A, David G, Ramirez-Gama M, Taylor P, Leung DYM, Gallo RL. Nat Med. 2021 Apr;27(4):700-709.
 Use of autologous bacteriotherapy to treat Staphylococcus aureus in patients with atopic dermatitis: A randomized double-blind clinical trial. Nakatsuji T, Gallo RL, Shafiq F, Tong Y, Chun K, Butcher AM, Cheng JY, Hata TR. JAMA Dermatol. 2021 Jun 16;157(8):978-82.
Acne (National Institute of Arthritis and Musculoskeletal and Skin Diseases/NIH)
Atopic Dermatitis (NIAMS)
Julie Segre (National Human Genome Research Institute/NIH)
Gallo Lab (University of California, San Diego)
[Note: Acting NIH Director Lawrence Tabak has asked the heads of NIH’s Institutes and Centers (ICs) to contribute occasional guest posts to the blog to highlight some of the cool science that they support and conduct. This is the fifth in the series of NIH IC guest posts that will run until a new permanent NIH director is in place.]