The NIH’s Researching COVID to Enhance Recovery (RECOVER) Initiative used a cohort study of more than 10,000 individuals with and without previous COVID-19 diagnoses and compared samples using 25 common laboratory tests in hopes a useful biomarker could be identified. They were unsuccessful.
Long COVID—or PASC—is an umbrella term for those with persistent post-COVID infection symptoms that negatively impact quality of life. Though it affects millions worldwide and has been called a major public health burden, the NIH/Langone study scientists noted one glaring problem: PASC is defined differently in the major tests they studied. This makes consistent diagnoses difficult.
The study brought to light possible roadblocks that prevented biomarker identification.
“This study is an important step toward defining long COVID beyond any one individual symptom,” said study author Leora Horwitz, MD (above), director of the Center for Healthcare Innovation and Delivery Science and co-principal investigator for the RECOVER CSC at NYU Langone, in a Langone Health news release. “This definition—which may evolve over time—will serve as a critical foundation for scientific discovery and treatment design.” In the future, clinical laboratories may be tasked with finding combinations of routine and reference tests that, together, enable a more precise and earlier diagnosis of long COVID. (Photo copyright: Yale School of Medicine.)
NIH/Langone Study Details
“The study … examined 25 routinely used and standardized laboratory tests chosen based on availability across institutions, prior literature, and clinical experience. These tests were conducted prospectively in laboratories that are certified by the Clinical Laboratory Improvement Amendments (CLIA). The samples were collected from 10,094 RECOVER-Adult participants, representing a diverse cohort from all over the US,” Inside Precision Medicine reported.
However, the scientists found no clinical laboratory “value” among the 25 tests examined that “reliably indicate previous infection, PASC, or the particular cluster type of PASC,” Inside Precision Medicine noted, adding that “Although some minor differences in the results of specific laboratory tests attempted to differentiate between individuals with and without a history of infection, these findings were generally clinically meaningless.”
“In a cohort study of more than 10,000 participants with and without prior SARS-CoV-2 infection, we found no evidence that any of 25 routine clinical laboratory values provide a reliable biomarker of prior infection, PASC, or the specific type of PASC cluster. … Overall, no evidence was found that any of the 25 routine clinical laboratory values assessed in this study could serve as a clinically useful biomarker of PASC,” the study authors wrote in Annals of Internal Medicine.
In addition to a vague definition of PASC, the NIH/Langone researchers noted a few other potential problems identifying a biomarker from the research.
“Use of only selected biomarkers, choice of comparison groups, if any (people who have recovered from PASC or healthy control participants); duration of symptoms; types of symptoms or phenotypes; and patient population features, such as sex, age, race, vaccination status, comorbidities, and severity of initial infection,” could be a cause for ambiguous results, the scientists wrote.
Future Research
“Understanding the basic biological underpinnings of persistent symptoms after SARS-CoV-2 infection will likely require a rigorous focus on investigations beyond routine clinical laboratory studies (for example, transcriptomics, proteomics, metabolomics) to identify novel biomarkers,” the study authors wrote in Annals of Internal Medicine.
“Our challenge is to discover biomarkers that can help us quickly and accurately diagnose long COVID to ensure people struggling with this disease receive the most appropriate care as soon as possible,” said David Goff, MD, PhD, director of the division of cardiovascular sciences at the NIH’s National Heart, Lung, and Blood Institute, in an NHLBI news release. “Long COVID symptoms can prevent someone from returning to work or school, and may even make everyday tasks a burden, so the ability for rapid diagnosis is key.”
“Approximately one in 20 US adults reported persisting symptoms after COVID-19 in June 2024, with 1.4% reporting significant limitations,” the NIH/Langone scientists wrote in their published study.
Astute clinical laboratory scientists will recognize this as possible future diagnostic testing. There is no shortage of need.
Though not biomarkers per se, these scores for certain genetic traits may someday be used by clinical laboratories to identify individuals’ risk for specific diseases
Can polygenic risk scores (a number that denotes a person’s genetic predisposition for certain traits) do a better job at predicting the likelihood of developing specific diseases, perhaps even before the onset of symptoms? Researchers at the Broad Institute of MIT and Harvard (Broad Institute) believe so, and their study could have implications for clinical laboratories nationwide.
In cooperation with medical centers across the US, the scientists “optimized 10 polygenic scores for use in clinical research as part of a study on how to implement genetic risk prediction for patients,” according to a Broad Institute news release.
The research team “selected, optimized, and validated the tests for 10 common diseases [selected from a total of 23 conditions], including heart disease, breast cancer, and type 2 diabetes. They also calibrated the tests for use in people with non-European ancestries,” the news release notes.
As these markers for genetic risk become better understood they may work their way into clinical practice. This could mean clinical laboratories will have a role in sequencing patients’ DNA to provide physicians with information about the probability of a patient’s elevated genetic risk for certain conditions.
However, the effectiveness of polygenic risk scores has faced challenges among diverse populations, according to the news release, which also noted a need to appropriately guide clinicians in use of the scores.
“With this work, we’ve taken the first steps toward showing the potential strength and power of these scores across a diverse population,” said Niall Lennon, PhD (above), Chief Scientific Officer of Broad Clinical Labs. “We hope in the future this kind of information can be used in preventive medicine to help people take actions that lower their risk of disease.” Clinical laboratories may eventually be tasked with performing DNA sequencing to determine potential genetic risk for certain diseases. (Photo copyright: Broad Institute.)
Polygenic Scores Need to Reflect Diversity
“There have been a lot of ongoing conversations and debates about polygenic risk scores and their utility and applicability in the clinical setting,” said Niall Lennon, PhD, Chair and Chief Scientific Officer of Broad Clinical Labs and first author of the study, in the news release. However, he added, “It was important that we weren’t giving people results that they couldn’t do anything about.”
In the paper, Lennon and colleagues explained polygenic risk scores “aggregate the effects of many genetic risk variants” to identify a person’s genetic predisposition for a certain disease or phenotype.
“But their development and application to clinical care, particularly among ancestrally diverse individuals, present substantial challenges,” they noted. “Clinical use of polygenic risk scores may ultimately prevent disease or enable its detection at earlier, more treatable stages.”
The scientists set a research goal to “optimize polygenic risk scores for a diversity of people.”
While performing the polygenic risk score testing on participants, Broad Clinical Labs focused on 10 conditions—including cardiometabolic diseases and cancer—selected by the research team based on “polygenic risk score performance, medical actionability, and clinical utility,” the Nature Medicine paper explained.
For each condition, the researchers:
Identified “exact spots in the genome that they would analyze to calculate the risk score.”
Used information from the NIH’s All of Us Research Program to “create a model to calibrate a person’s polygenic risk score according to that individual’s genetic ancestry.”
The All of Us program, which aims to collect health information from one million US residents, has three times more people of non-European ancestry than other data sources developing genetic risk scores, HealthDay News reported.
20% of Study Participants Showed High Risk for Disease
To complete their studies, Broad Institute researchers processed a diverse group of eMERGE participants to determine their clinical polygenic risk scores for each of the 10 diseases between July 2022 and August 2023.
Listed below are all conditions studied, as well as the number of participants involved in each study and the number of people with scores indicating high risk of the disease, according to their published paper:
Over 500 people (about 20%) of the 2,500 participants, had high risk for at least one of the 10 targeted diseases, the study found.
Participants in the study self-reported their race/ancestry as follows, according to the paper:
White: 32.8%
Black: 32.8%
Hispanic: 25.4%
Asian: 5%
American Indian: 1.5%
Middle Eastern: 0.9%
No selection: 0.8%
“We can’t fix all biases in the risk scores, but we can make sure that if a person is in a high-risk group for a disease, they’ll get identified as high risk regardless of what their genetic ancestry is,” Lennon said.
Further Studies, Scoring Implications
With 10 tests in hand, Broad Clinical Labs plans to calculate risk scores for all 25,000 people in the eMERGE network. The researchers also aim to conduct follow-up studies to discover what role polygenic risk scores may play in patients’ overall healthcare.
“Ultimately, the network wants to know what it means for a person to receive information that says they’re at high risk for one of these diseases,” Lennon said.
The researchers’ findings about disease risk are likely also relevant to healthcare systems, which want care teams to make earlier, pre-symptomatic diagnosis to keep patients healthy.
Clinical laboratory leaders may want to follow Broad Clinical Labs’ studies as they perform the 10 genetic tests and capture information about what participants may be willing to do—based on risk scores—to lower their risk for deadly diseases.
Discovery highlights how ongoing microbiome research points to new opportunities that can lead to development of more effective cancer screening clinical laboratory tests
New research from the Fred Hutchinson Cancer Center in Seattle once again demonstrates that the human microbiome plays a sophisticated role in many biological processes. Microbiologists and anatomic pathologists who diagnose tissue/biopsies will find this study’s findings intriguing.
This breakthrough in colon cancer research came from the discovery that a “subspecies” of a common type of a bacteria that resides in the mouth and causes dental plaque also “shields tumor cells from cancer treatment,” according to NBC News.
The scientists inspected colorectal cancer (CRC) tumors and found that 50% of those examined featured a subspecies of Fusobacterium nucleatum (F. nucleatum or Fn) and that this anaerobic bacterium was “shielding tumor cells from cancer-fighting drugs,” NBC News noted. Many of these tumors were considered aggressive cases of cancer.
“The discovery, experts say, could pave the way for new treatments and possibly new methods of screening,” NBC News reported.
“Patients who have high levels of this bacteria in their colorectal tumors have a far worse prognosis,” Susan Bullman, PhD (above), who jointly supervised the Fred Hutch research team and who is now Associate Professor of Immunology at MD Anderson Cancer Center, told NBC News. “They don’t respond as well to chemotherapy, and they have an increased risk of recurrence,” she added. Microbiologists and clinical laboratories working with oncologists on cancer treatments will want to follow this research as it may lead to new methods for screening cancer patients. (Photo copyright: Fred Hutchinson Cancer Center.)
Developing Effective Treatments
Susan Bullman, PhD, Associate Professor of Immunology at MD Anderson Cancer Center, who along with her husband and fellow researcher Christopher D. Johnston, PhD, Assistant Professor at Fred Hutchinson Cancer Center, jointly supervised an international team of scientists that examined the genomes of 80 F. nucleatum strains from the mouths of cancer-free patients and 55 strains from tumors in patients with colorectal cancer, according to the National Institutes of Health (NIH). The NIH funded the research.
The researchers targeted a subspecies of F. nucleatum called F. nucleatum animalis (Fna) that “was more likely to be present in colorectal tumors. Further analyses revealed that there were two distinct types of Fna. Both were present in mouths, but only one type, called Fna C2, was associated with colorectal cancer” the NIH wrote in an article on its website titled, “Gum Disease-related Bacteria Tied to Colorectal Cancer.”
“Tumor-isolated strains predominantly belong to Fn subspecies animalis (Fna). However, genomic analyses reveal that Fna, considered a single subspecies, is instead composed of two distinct clades (Fna C1 and Fna C2). Of these, only Fna C2 dominates the CRC tumor niche,” the Fred Hutch researchers wrote in their Nature paper.
“We have pinpointed the exact bacterial lineage that is associated with colorectal cancer, and that knowledge is critical for developing effective preventive and treatment methods,” Johnston told the NIH.
How Bacteria Got from Mouth to Colon Not Fully Understood
Traditionally, F. nucleatum makes its home in the mouth in minute quantities. Thus, it is not fully understood how these bacteria travel from the mouth to the colon. However, the Fred Hutch researchers showed that Fna C2 could survive in acidic conditions, like those found in the gut, longer than the other types of Fna. This suggests that the bacteria may travel along a direct route through the digestive tract.
The study, which focused on participants over 50, comes at a time when colorectal cancer rates are trending upward. Rates are doubling for those under 55, jumping from 11% in 1995 to 20% in 2019. CRC is the second-leading cancer death and over 53,000 will succumb to the disease in 2024, according to NBC News.
Many of the newer diagnoses are in later stages with no clear reason why, and the Fred Hutch scientists are trying to understand how their findings tie into the increase of younger cases of colon cancer.
Bullman says it will be important to look at “whether there are elevated levels of this bacterium in young onset colorectal cancer, which is on the rise globally for unknown reasons,” she told NBC News.
Possibility of More Effective Cancer Screening
There is hope that scientists equipped with this knowledge can develop new and more effective screening and treatment options for colon cancer, as well as studying the microbiome’s impact on other diseases.
On the prevention side, researchers have seen that in mice the addition of Fna “appeared to cause precancerous polyps to form, one of the first warning signs of colorectal cancer, though Bullman added that this causation hasn’t yet been proven in humans.” NBC reported.
Future research may find that screening for Fna could determine if colorectal tumors will be aggressive, NIH reported.
“It’s possible that scientists could identify the subspecies while it’s still in the mouth and give a person antibiotics at that point, wiping it out before it could travel to the colon,” Bullman told NBC News. “Even if antibiotics can’t successfully eliminate the bacteria from the mouth, its presence there could serve as an indication that someone is at higher risk for aggressive colon cancer.”
There is also the thought of developing antibiotics to target a specific subtype of bacteria. Doing so would eliminate the need to be “wiping out both forms of the bacteria or all of the bacteria in the mouth. Further, it’s relevant to consider the possibility of harnessing the bacteria to do the cancer-fighting work,” NBC noted.
“The subtype has already proven that it can enter cancer cells quite easily, so it might be possible to genetically modify the bacteria to carry cancer-fighting drugs directly into the tumors,” Bullman told NBC News.
Further studies and research are needed. However, the Fred Hutch researchers’ findings highlight the sophistication of the human microbiome and hint at the potential role it can play in the diagnosis of cancer by clinical laboratories and pathology groups, along with better cancer treatments in the future.
Study of the 50 Omicron variants could lead to new approaches to clinical laboratory testing and medical treatments for long COVID
Patients infected with SARS-CoV-2 can usually expect the COVID-19 illness to subside within a couple of weeks. However, one Dutch patient remained infected with the coronavirus for 612 days and fought more than 50 mutations (aka, variants) before dying late last year of complications due to pre-existing conditions. This extreme case has given doctors, virologists, microbiologists, and clinical laboratories new insights into how the SARS-CoV-2 virus mutates and may lead to new treatments for long COVID.
The medication the patient was taking for his pre-existing conditions may have contributed to his body being unable to produce antibodies in response to three shots of the Moderna mRNA COVID vaccine he received.
Magda Vergouwe, MD, PhD candidate at the Center for Experimental and Molecular Medicine (CEMM), Amsterdam UMC, who lead a study into the patient, theorized that some of the medications the patient was on for his pre-existing conditions could have destroyed healthy cells alongside the abnormal cancer-causing B cells the drugs were meant to target.
“This case underscores the risk of persistent SARS-CoV-2 infections in immunocompromised individuals,” the researchers said prior to presenting their report about the case at a meeting of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) in Barcelona, Spain, Time reported. “We emphasize the importance of continuing genomic surveillance of SARS-CoV-2 evolution in immunocompromised individuals with persistent infections.”
“Chronic infections and viral evolution [are] commonly described in [the] literature, and there are other cases of immunocompromised patients who have had [COVID] infections for hundreds of days,” Magda Vergouwe, MD, PhD candidate (above), Center for Experimental and Molecular Medicine at Amsterdam UMC, told Scientific American. “But this is unique due to the extreme length of the infection … and with the virus staying in his body for so long, it was possible for mutations to just develop and develop and develop.” Microbiologists, virologists, and clinical laboratories involved in testing patients with long COVID may want to follow this story. (Photo copyright: LinkedIn.)
Risks to Immunocompromised Patients
Pre-existing conditions increase the risk factor for COVID-19 infections. A 2021 study published in the Journal of the American Board of Family Medicine (JABFM) titled, “Prevalence of Pre-existing Conditions among Community Health Center Patients with COVID-19,” found that about 61% of that study’s test group had a pre-existing condition prior to the outbreak of the COVID-19 pandemic.
When the Dutch man was admitted to Amsterdam UMC with common and serious COVID-19 symptoms, such as shortness of breath, a cough, and low blood oxygen levels, he was prescribed sotrovimab (a monoclonal antibody) along with other COVID treatments.
About a month after being admitted his COVID-19 symptoms decreased, so he was first discharged to a rehab facility and then finally to his home. However, he continued to test positive for the coronavirus and developed other infections that may have been complicated by the persistent case of COVID-19.
The Amsterdam UMC doctors emphasized that the man ultimately succumbed to his pre-existing conditions and not necessarily COVID-19.
“It’s important to note that in the end he did not die from his COVID-19,” Vergouwe told Scientific American. “But he did keep it with him for a very long period of time until then, and this is why we made sure to sample [the virus in his body] as much as we could.”
One in Five Adults Develop Long COVID
Long COVID does not necessarily indicate an active infection. However, in as many as one in five US adults COVID symptoms persist after the acute phase of the infection is over, according to a study published recently in JAMA Network Open titled, “Epidemiologic Features of Recovery from SARS-CoV-2 Infection.”
“In this cohort study, more than one in five adults did not recover within three months of SARS-CoV-2 infection. Recovery within three months was less likely in women and those with pre-existing cardiovascular disease and more likely in those with COVID-19 vaccination or infection during the Omicron variant wave,” the JAMA authors wrote.
The origins of long COVID are not entirely clear, but according to the National Institutes of Health (NIH) it can develop when a patient is unable to sufficiently rest while battling off the initial virus. According to Vergouwe, the SARS-CoV-2 genome will always grow quicker when found in a patient with a compromised immune system.
Unique COVID-19 Mutations
More than 50 new mutations of the original Omicron variant were identified in the Dutch patient. According to Vergouwe, “while that number can sound shocking, mutations to the SARS-CoV-2 genome are expected to evolve more quickly in those who are immunocompromised (the average mutation rate of the virus is estimated to be two mutations per person per month),” Scientific American reported. “What does make these mutations unusual, she noted, is how their features differed vastly from mutations observed in other people with COVID. [Vergouwe] hypothesizes that the exceptional length of the individual’s infection, and his pre-existing conditions, allowed the virus to evolve extensively and uniquely.”
COVID-19 appears to be here to stay, and most clinical laboratory managers and pathologists understand why. As physicians continue to learn about the SARS-CoV-2 coronavirus, this is another example of how the knowledge about SARS-CoV-2 is growing as different individuals are infected with different variants of the virus.
Study results from Switzerland come as clinical laboratory scientists seek new ways to tackle the problem of antimicrobial resistance in hospitals
Microbiologists and clinical laboratory scientists engaged in the fight against antibiotic-resistant (aka, antimicrobial resistant) bacteria will be interested in a recent study conducted at the University of Basel and University Hospital Basel in Switzerland. The epidemiologists involved in the study discovered that some of these so-called “superbugs” can remain in the body for as long as nine years continuing to infect the host and others.
The researchers wanted to see how two species of drug-resistant bacteria—K. pneumoniae and E. coli—changed over time in the body, according to a press release from the university. They analyzed samples of the bacteria collected from patients who were admitted to the hospital over a 10-year period, focusing on older individuals with pre-existing conditions. They found that K. pneumoniae persisted for up to 4.5 years (1,704 days) and E. coli persisted for up to nine years (3,376 days).
“These patients not only repeatedly become ill themselves, but they also act as a source of infection for other people—a reservoir for these pathogens,” said Lisandra Aguilar-Bultet, PhD, the study’s lead author, in the press release.
“This is crucial information for choosing a treatment,” explained Sarah Tschudin Sutter, MD, Head of the Division of Infectious Diseases and Hospital Epidemiology, and of the Division of Hospital Epidemiology, who specializes in hospital-acquired infections and drug-resistant pathogens. Sutter led the Basel University study.
“The issue is that when patients have infections with these drug-resistant bacteria, they can still carry that organism in or on their bodies even after treatment,” said epidemiologist Maroya Spalding Walters, MD (above), who leads the Antimicrobial Resistance Team in the Division of Healthcare Quality Promotion at the federal Centers for Disease Control and Prevention (CDC). “They don’t show any signs or symptoms of illness, but they can get infections again, and they can also transmit the bacteria to other people.” Clinical laboratories working with microbiologists on antibiotic resistance will want to follow the research conducted into these deadly pathogens. (Photo copyright: Centers for Disease Control and Prevention.)
COVID-19 Pandemic Increased Antibiotic Resistance
The Basel researchers looked at 76 K. pneumoniae isolates recovered from 19 patients and 284 E. coli isolates taken from 61 patients, all between 2008 and 2018. The study was limited to patients in which the bacterial strains were detected from at least two consecutive screenings on admission to the hospital.
“DNA analysis indicates that the bacteria initially adapt quite quickly to the conditions in the colonized parts of the body, but undergo few genetic changes thereafter,” the Basel University press release states.
The researchers also discovered that some of the samples, including those from different species, had identical mechanisms of drug resistance, suggesting that the bacteria transmitted mobile genetic elements such as plasmids to each other.
One limitation of the study, the authors acknowledged, was that they could not assess the patients’ exposure to antibiotics.
Meanwhile, recent data from the World Health Organization (WHO) suggests that the COVID-19 pandemic might have exacerbated the challenges of antibiotic resistance. Even though COVID-19 is a viral infection, WHO scientists found that high percentages of patients hospitalized with the disease between 2020 and 2023 received antibiotics.
“While only 8% of hospitalized patients with COVID-19 had bacterial co-infections requiring antibiotics, three out of four or some 75% of patients have been treated with antibiotics ‘just in case’ they help,” the WHO stated in a press release.
WHO uses an antibiotic categorization system known as AWaRe (Access, Watch, Reserve) to classify antibiotics based on risk of resistance. The most frequently prescribed antibiotics were in the “Watch” group, indicating that they are “more prone to be a target of antibiotic resistance and thus prioritized as targets of stewardship programs and monitoring.”
“When a patient requires antibiotics, the benefits often outweigh the risks associated with side effects or antibiotic resistance,” said Silvia Bertagnolio, MD, Unit Head in the Antimicrobial resistance (AMR) Division at the WHO in the press release. “However, when they are unnecessary, they offer no benefit while posing risks, and their use contributes to the emergence and spread of antimicrobial resistance.”
Citing research from the National Institutes of Health (NIH), NPR reported that in the US, hospital-acquired antibiotic-resistant infections increased 32% during the pandemic compared with data from just before the outbreak.
“While that number has dropped, it still hasn’t returned to pre-pandemic levels,” NPR noted.
The UPenn researchers have already developed an antimicrobial treatment derived from guava plants that has proved effective in mice, Vox reported. They’ve also trained an AI model to scan the proteomes of extinct organisms.
“The AI identified peptides from the woolly mammoth and the ancient sea cow, among other ancient animals, as promising candidates,” Vox noted. These, too, showed antimicrobial properties in tests on mice.
These findings can be used by clinical laboratories and microbiologists in their work with hospital infection control teams to better identify patients with antibiotic resistant strains of bacteria who, after discharge, may show up at the hospital months or years later.
