New studies show that children and teens are developing long COVID at higher rates—especially after multiple infections. Here’s how clinical labs can play a vital role in identifying at-risk patients and supporting early intervention.
As the healthcare system continues to grapple with the lingering effects of COVID-19, new research is drawing attention to a growing—and often overlooked—population: children and teens with long COVID. For clinical laboratory leaders, these findings underscore the continued importance of SARS-CoV-2 testing, variant monitoring, and post-infection diagnostics in younger patients. Studies reviewed by the Center for Infectious Disease Research and Policy (CIDRAP) and others show that long COVID is not only prevalent in youth but more likely to develop after reinfection. With an estimated one million U.S. children already affected, labs play a critical role in helping clinicians identify and manage post-viral complications while providing data that inform vaccine and reinfection risk strategies.
The pooled results of the studies found that long COVID prevalence was 36% among patients who had become infected with the SARS-CoV-2 infection. The highest prevalence was found in South America, and risk factors included being unvaccinated for the virus, contracting a pre-Omicron variant, and being of the female sex.
Another study analyzed from The Journal of Infectious Diseases focused on the effects of long COVID on adolescents in the summer of 2022. In that study, at least one symptom lasted for four weeks or more for 41% of the respondents who also tested positive for a SARS-CoV-2 infection. Adolescents in the study who tested positive also had increased odds of developing neurological symptoms that lasted three months or longer compared to the adolescents in the study who tested negative for SARS-CoV-2. However, the study also concluded that most symptoms are resolved within three months of infection.
Risk Increases with Multiple Infections
The New York Timesrecently reported that a study published in Lancet Infectious Diseases found that children and teenagers are twice as likely to develop long COVID if they became infected with the virus more than once. The study was a part of the National Institutes of Health’s RECOVER Initiative by examining the records of around 465,000 young people under 21 at 40 United States children’s hospitals.
Over a six-month period, it was found that 1,884 per million young people would develop long COVID after being infected with the virus twice, whereas only 904 per million young people developed long COVID after one infection. The exact numbers of young people with long COVID is not known. However, the Centers for Disease Control and Prevention (CDC) estimates the number stands at about 1 million American children, or 1.3% of the population under 18. A similar trend is seen in adults with long COVID.
These numbers are likely conservative, and the issue of long COVID among youth may be more widespread. According to the same study, tens of thousands of young people in the study were treated for conditions associated with long COVID, such as respiratory symptoms and abdominal pain. Yong Chen, PhD, senior author of the study and professor of Biostatistics at Department of Biostatistics, Epidemiology, and Informatics (DBEI), and a Senior Scholar at Center for Clinical Epidemiology & Biostatistics (CCEB) at the University of Pennsylvania (Penn) Perelman School of Medicine, noted the limitations of the diagnostic code. As quoted by The New York Times, he called the findings a mere “subset of the long COVID.”
Yong Chen, PhD, professor of Biostatistics at DBEI, and a Senior Scholar at CCEB at the University of Pennsylvania (Penn) Perelman School of Medicine said, “Your body really has a memory system and is really going to be hurt from recurrent infection.” (Photo credit: University of Pennsylvania)
Mitigating Risk
Now that we are over five years past the initial worldwide lockdowns, the public has begun to live with significantly less fear–– but the risk remains. “People think that reinfections don’t matter as much and don’t take them seriously,” Chen told Time, “Our primary message is that reinfections still matter, and you should do what you can to avoid reinfection by taking a vaccine or wearing a mask.”
However, the CDC has recently approved recommendations made by Health and Human Services Secretary, Robert F. Kennedy Jr., to remove the blanket recommendation for adults 65 and older to be vaccinated against COVID-19 and recommended that patients between six months and 64 years should discuss with their doctors. Critics of the move warn that these ‘softer’ recommendations may limit insurance coverage of the vaccines.
Clinical laboratory professionals should remain vigilant as research continues to reveal how long COVID affects younger populations. The persistence and variability of post-COVID symptoms highlight the need for continued diagnostic vigilance and testing innovation—not only to confirm infection but to monitor lingering inflammatory, respiratory, or neurological effects. By maintaining awareness of evolving studies and updated guidance from public health agencies, labs can help clinicians identify which patients may be at higher risk for long-term complications. Moreover, laboratory data can support broader efforts to track reinfection patterns, inform vaccine strategies, and guide local health systems in managing the ongoing burden of COVID-related chronic illness.
The federal agency says it will mandate randomized, controlled clinical trials for vaccination of younger, healthy individuals
It’s been a confusing past few weeks in terms of what the general public’s access to COVID-19 vaccinations will be like in the future.
Public health experts have been verbally jousting with the federal Department of Health and Human Services (HHS) about moves its health officials made recently regarding the vaccines. This could put clinical laboratories on the front lines to help determine whether COVID cases—particularly severe ones—eventually rise as a result.
Food and Drug Administration (FDA) commissioner Martin A. Makary, MD, MPH, and Vinay Prasad, MD, MPH, who leads the agency’s vaccine oversight, announced on May 20 that the agency will require randomized, controlled clinical trials before approving COVID vaccines for healthy individuals under age 65.
“While all other high-income nations confine vaccine recommendations to older adults (typically those older than 65 years of age), or those at high risk for severe COVID-19, the United States has adopted a one-size-fits-all regulatory framework and has granted broad marketing authorization to all Americans over the age of 6 months,” Makary and Prasad wrote in NEJM.
Under the new framework, they noted, the agency expects that it will continue to approve vaccines for adults over 65 as well as younger people with health conditions that put them at high risk of severe outcomes from COVID-19.
The range of diseases is “vast, including obesity and even mental health conditions such as depression,” they wrote. “Estimates suggest that 100 million to 200 million Americans will have access to vaccines in this manner.”
In their NEJM commentary, FDA commissioner Martin Makary, MD (left), and Vinay Prasad, MD (right), wrote, “Moving forward, the FDA will adopt the following COVID-19 vaccination regulatory framework: On the basis of immunogenicity—proof that a vaccine can generate antibody titers in people.” (Photo copyrights: Wikimedia Commons.)
Former CDC APIC Member Pushes Back
The announcement drew criticism from public health and medical experts.
“The FDA guidance presented in the NEJM was not released in the Federal Register, did not invite comment, and provided only a general outline for COVID-19 vaccine licensure,” wrote pediatrician and vaccinologist Kathryn M. Edwards, MD, in a commentary for STAT. Edwards is a former member of the Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP), which makes vaccine recommendations to the agency.
On June 9, in an opinion piece for The Wall Street Journal, HHS Secretary Robert F. Kennedy Jr. announced that he’s removing all 17 current members of ACIP.
“The FDA mandate is to ensure safe and effective vaccines based on the clinical studies performed, but not to develop specific recommendations for their use,” Edwards added. “Providing recommendations on vaccine use for the civilian population is the mandate of the ACIP.”
Edwards contended that extensive data is already available on the safety and effectiveness of COVID-19 vaccines. She stated that “there is no precedent for mandating continued placebo-controlled randomized clinical trials for vaccines that have already been licensed.”
New Policy Announcement Raises Questions
The New York Times notes that many questions remain about the specifics of the new policy and how broadly the vaccines will be available.
A likely scenario, the paper reported, is that health insurers will play a role as “gatekeepers by demanding medical documentation of an underlying condition before agreeing to cover the cost.” Without insurance coverage, people would likely pay approximately $140 per shot out of pocket.
This stands in contrast to European countries, where outreach campaigns target specific populations based on public health recommendations. according to Forbes. However, “in virtually all instances, COVID-19 vaccines can be gotten free of charge across Europe regardless of health or age status,” the article notes.
In their NEJM commentary, Prasad and Makary noted that adoption of the annual COVID-19 booster shot is already low. The CDC reported that 23% of Americans 18 and older received vaccinations in the 2024-2025 season, up slightly from 21.6% in 2023-2024.
Kennedy Steps In
On May 27, Kennedy announced in a video on X that the CDC would remove the COVID-19 vaccine from the recommended immunization schedule for healthy children and healthy pregnant women. Previously, the CDC recommended the vaccine for everyone ages six months and older.
Kennedy was joined in the video by Makary and National Institutes of Health director Jay Bhattacharya MD, PhD.
However, CDC staffers were “blindsided” by the announcement, NPR reported, citing an agency official who requested anonymity.
“Hours after the post on X, CDC staffers received a directive from Secretary Kennedy—dated May 19, but sent May 27—rescinding the department’s 2022 acceptance of the CDC’s recommendations for the use of COVID shots in children and during pregnancy,” NPR reported.
It now appears that HHS has at least partially backtracked on Kennedy’s announcement.
The CDC’s immunization schedule now states that vaccination of healthy children should be a matter of “shared clinical decision-making” between the doctor and parent or patient.
“After confusing, mixed messages from leaders at HHS earlier this week, we are relieved to see today that the CDC updated its schedules for child and adolescent immunizations to allow families to maintain the choice to immunize their children against COVID in consultation with their doctor,” American Academy of Pediatrics president Susan Kressly said in a statement from the organization.
In a June 1 interview with the CBS News program “Face the Nation,” Makary confirmed that the recommendation to vaccinate “should be with the patient and their doctor.”
However, he also criticized ACIP as a “kangaroo court where they just rubber stamp every single vaccine put in front of them.”
Insurers continued receiving payments even after beneficiaries moved to other states, the paper reported
As Congress considers cuts in Medicaid funding, The Wall Street Journal reported that Medicaid managed care plans received at least $4.3 billion in duplicate payments over a three-year period, due to recipients who moved from one state to another.
Centene, the largest private Medicaid insurer, collected $620 million in duplicate payments between 2019 and 2021, while Elevance Health received $346 million and UnitedHealth Group took in $298 million, The Journal reported on March 26.
All told, more than 270 insurers received duplicate payments. The paper noted that private insurers handle coverage for 70% of the 72 million Medicaid recipients.
“We may be paying premiums on behalf of an individual who might have moved, and we don’t know that they have moved,” healthcare consultant Caprice Knapp, PhD, told the newspaper. “It definitely is wasteful.”
The reporting was based on an analysis of the Transformed Medicaid Statistical Information System (T-MSIS), a database of beneficiary information maintained by the Centers for Medicare and Medicaid Services (CMS).
In response to a Wall Street Journal article about managed care plans receiving billions in duplicate Medicaid payments, Craig Kennedy, chief executive of Medicaid Health Plans of America, noted how heavily regulated the health insurance industry is. (Photo copyright: LinkedIn.)
Multiple States Paid Double Payments to Medicaid Insurers
“Government guidelines stipulate that if Medicaid recipients move to another state, they are supposed to cancel their coverage in their former state when signing up in the new one, which often gives them a different insurer,” The Journal reported. “But the recipients don’t always cancel, leaving states to play catch-up.”
States paying the highest rates of duplicate payments include Georgia, Florida, and Indiana, according to The Wall Street Journal’s report.
To illustrate how this works, the story used the hypothetical example of a Medicaid recipient in Florida. There, the state pays $291 per month to the private Medicaid insurer. The individual moves to Georgia and enrolls in that state’s Medicaid program. Georgia begins paying an insurer $339 per month. But Florida continues to pay the monthly fee even though the recipient is now receiving medical care in Georgia. (The payment amounts are estimates based on averages in each state, the paper said.)
The state might not know that a beneficiary has moved until it conducts an annual eligibility check, the story noted. In the meantime, insurers “can collect months of payments before a patient is dropped from the rolls.”
To determine if a patient had moved, the analysis looked at where they received medical care. “The data don’t indicate where recipients are actually living or reflect all adjustments later made to payments,” the story noted.
Some insurers criticized the analysis. Most of the three-year period overlapped with the COVID-19 pandemic, when emergency rules made it difficult to disenroll beneficiaries, insurers told The Wall Street Journal. A Centene spokesman said the analysis “ignores the financial safeguards in place to address potential overpayments.” The insurer told the paper that it had repaid $2 billion to the states between 2019 and 2021.
The duplicate payments amounted to $800 million in 2019, then jumped to $1.3 billion in 2020 and $2.1 billion in 2021, the paper reported. KFF, citing CMS data, reported that states spent an estimated $880 billion on Medicaid programs in fiscal year 2023.
Craig Kennedy, chief executive at Medicaid Health Plans of American—an industry group that represents managed care organizations—told The Journal that insurers are closely watched by regulators.
“[Health insurance is] a heavily regulated industry,” Kennedy said. “Following rules and regulations is the No. 1 priority here.”
Office of Inspector General Weighs In
The Wall Street Journal analysis followed an earlier report from the US Department of Health and Human Services’ (HHS) Office of Inspector General (OIG). The OIG report, issued in September 2022, was based on an audit covering Medicaid managed care capitation payments in August 2019 and August 2020. It was also based on data from T-MSIS.
“All 47 States reviewed made capitation payments on behalf of Medicaid beneficiaries who were concurrently enrolled in two States,” the OIG reported. “Specifically, capitation payments were made on behalf of 208,254 concurrently enrolled beneficiaries in August 2019 and 327,497 concurrently enrolled beneficiaries in August 2020. The Medicaid program incurred costs of approximately $72.9 million in August 2019 and $117.1 million in August 2020 for capitation payments associated with beneficiaries in one of the two concurrently enrolled States.”
OIG advised CMS to provide state agencies with T-MSIS enrollment data. CMS dismissed the recommendation, claiming that the Public Assistance Reporting Information System (PARIS), designed to deter improper public assistance payments, was sufficient, and that T-MSIS would add inefficiency and confusion. However, current and former state Medicaid officials told The Wall Street Journal that PARIS “doesn’t always include up-to-date or complete information.”
Even a 10% decline in vaccination rates would cause cases to skyrocket, leading to massive increase in demand for clinical laboratory MMR testing
As policymakers consider revisions to the current childhood vaccination schedule, a simulation model developed at Stanford University projects that declines in vaccination rates could lead to a dramatic resurgence of measles and other preventable infectious diseases over the next 25 years. Even at current vaccination rates, measles could once again become endemic in the US within two decades, the researchers reported.
The model suggests that clinical laboratories could one day find themselves testing millions of children for diseases once thought to be nearly eliminated in the US.
“With measles, we’re right on the cusp,” said senior author Nathan Lo, MD, PhD, assistant professor of infectious diseases, in a Stanford Medicine press release. “Increasing vaccination levels by just 5% brings the number of measles cases down, safely away from returning to endemic levels.”
“We’ve seen a worrisome pattern of decreasing routine childhood vaccinations,” said study senior author Nathan Lo, MD, PhD, in a Stanford Medicine press release. (Photo copyright: Stanford University.)
Millions of Measles Cases Predicted if Vaccinations Drop
To complete their study, the researchers looked at four infectious diseases:
“We used a large-scale epidemiological model to simulate all individuals living in the US and assigned them an age, vaccination status, immunity, state of residence, etc.,” Lo explained. “We then simulated how infections would spread under different vaccine conditions.”
Each state was modeled independently to account for variations in risk, noted lead author Mathew Kiang, ScD, assistant professor in the department of epidemiology and population health at Stanford. For example, Massachusetts is considered low risk due to high vaccination rates, whereas Texas and California are “higher risk because vaccination rates in both have dropped and there’s a lot of travel to those states,” he said.
The model assumed that infections would not cross state lines, “so the numbers could be an underestimate,” Kiang said.
He painted a grim picture of the scenarios projected by the model.
“If vaccination were to fall by even 10% today, measles cases would skyrocket to 11.1 million over the next 25 years,” he said. “If vaccination rates were cut in half, we’d expect 51.2 million cases of measles, 9.9 million cases of rubella, 4.3 million cases of polio, and 200 cases of diphtheria over 25 years. This would lead to 10.3 million hospitalizations and 159,200 deaths, plus an estimated 51,200 children with post-measles neurological complications, 10,700 cases of birth defects due to rubella, and 5,400 people paralyzed from polio.”
Lo suggested a more hopeful scenario in which “some fraction of the unvaccinated population seeks vaccination” as the diseases spread over the next decade. However, “if that were to happen, you can’t just flip a switch—once these diseases get unleashed, it would take time eliminate them again,” he said.
As of May 22, 2025, 1,046 cases of measles have been reported in the US this year, according to the Centers for Disease Control and Prevention. This year has been among the most active for measles since 2000. For the whole of 2024, 285 cases were reported.
More Contagious than COVID-19
All four diseases are far more contagious than COVID-19, Lo said, but measles “is in a different ballpark” as one of the most infectious diseases known to medicine. In a fully susceptible population, he said, one person can infect up to 20 individuals, but for the purposes of the simulation, they used a more conservative estimate of 12.
“There was a disruption to healthcare services during the pandemic, but declines preceded this period and have accelerated since then for many reasons,” he noted. “People look around and say, ‘We don’t see these diseases. Why should we vaccinate against them?’ There’s a general fatigue with vaccines. And there’s distrust and misinformation about vaccine effectiveness and safety.”
Another concern with measles is that the MMR vaccine “has become particularly controversial, partly due to a history of fraudulent medical research that raised safety concerns,” Lo said.
He added that compared to the other diseases, measles is more prevalent globally.
“Travelers importing a disease are like matches, and US under-vaccination is the tinder,” Kiang said. “With measles, you’re throwing a lot of matches in, and eventually something is going to happen.”
Study shows clinical laboratories may one day use nanorobotic tests to help prevent spread of viral infections, cancer, and other diseases
Scientists from the University of Illinois Urbana-Champaign (U of I) have developed a tiny robotic “hand” made from structural DNA that “grabs” viruses—including the COVID-19 coronavirus—potentially preventing them from infecting cells. Such a nano-robotic antiviral technology could be used by anatomic pathologists and clinical laboratory managers in the future as a point-of-care type of test.
This is yet another example of out-of-the-box thinking by developers of diagnostic technology. Led by Xing Wang, PhD, professor of bioengineering and of chemistry at the U of I, the scientists dubbed their DNA device the NanoGripper.
Similar to a piece of origami (Japanese art of folded paper), the so-called hand has “four bendable fingers and a palm, all in one nanostructure folded from a single piece of DNA,” according to a U of I news release. The scientists found in their study that the hand was capable of doing a rapid test to identify the (COVID-19) virus and “prevented the viral spike proteins from infecting the cells,” Gizmodo reported.
“We are using DNA for its structural properties. It is strong, flexible, and programmable. Yet even in the DNA origami field, this is novel in terms of the design principle. We fold one long strand of DNA back and forth to make all of the elements, both the static and moving pieces, in one step,” said Wang in the news release.
“It would be very difficult to apply it after a person is infected, but there’s a way we could use it as a preventive therapeutic,” said Xing Wang, PhD (above), associate professor, bioengineering and chemistry, University of Illinois Urbana-Champaign, in a news release. “We could make an anti-viral nasal spray compound. The nose is the hot spot for respiratory viruses, like COVID or influenza. A nasal spray with the NanoGripper could prevent inhaled viruses from interacting with the cells in the nose.” Clinical laboratories may one day perform antiviral testing that uses U of I’s NanoGripper technology. (Photo copyright: University of Illinois.)
How a DNA Nanorobot Grabs a Virus
The U of I researchers wanted to leverage what has been discovered about DNA as a “material for constructing versatile nanorobots for biomedical applications,” they wrote in Science Robotics. However, previous studies had not achieved the current origami design of a nanoscale mechanism, the authors added.
With robotic precision and its DNA structure, the researchers’ NanoGripper moves and enables fingers to bend for “customized interactions with target molecules,” Interesting Engineering reported, adding that the technology also:
Employed DNA aptamers on the fingers which act as “molecular locks” to find and bind to specific targets.
In a demonstration, wrapped its fingers around the target spike protein of the COVID-19 coronavirus, essentially “disabling its ability to infect cells.”
“The aptamers are arranged into a spatial pattern that specifically matches that of the trimeric spike protein on the virus outer surface. Such pattern recognition-enabled multivalent interaction—a principle developed by my group—has induced ultrahigh NanoGripper virus-binding avidity, resulting in enhanced virus diagnosis sensitivity,” Wang said.
Taken from the U of I news release, the image above shows how “Inspired by the gripping power of the human hand and bird claws, the researchers designed the NanoGripper with four bendable fingers and a palm, all in one nanostructure folded from a single piece of DNA. Each finger has three joints, like a human finger, and the angle and degree of bending are determined by the design on the DNA scaffold.” Such nano-robotic technology could become a new clinical laboratory test for diagnosing viral infections, or even a preventative treatment if caught prior to infection. (Photo and caption copyright: University of Illinois.)
Developing a Test for COVID-19
The scientists discovered that when equipped with a photonic crystal sensor, NanoGripper detected the SARS-CoV-2 coronavirus in 30 minutes with sensitivity equal to RTqPCR tests, Gizmodo reported.
“The NanoGripper functions as a highly sensitive biosensor that selectively detects intact SARS-CoV-2 virions in human saliva with a limit of detection of 100 copies per milliliter, providing a sensitivity equal to that of reverse transcription quantitative polymerase chain reaction [RTqPCR],” the authors wrote in Science Robotics.
In fact, the NanoGripper test is reportedly faster and easier than RTqPCR testing, which requires sophisticated instruments.
“Our test is very fast and simple since we detect the intact virus directly,” said study collaborator Brian Cunningham, PhD, professor, electrical and computer engineering and bioengineering at U of I, in the news release.
“When the virus is held in the NanoGripper’s hand, a fluorescent molecule is triggered to release light when illuminated by an LED or laser,” he said, adding, “When a large number of fluorescent molecules are concentrated upon a single virus, it becomes bright enough in our detection system to count each virus individually.”
More Research and Applications
Gizmodo compared the NanoGripper to a “true Swiss army knife,” able to change and detect other viruses such as HIV and influenza (Flu).
The U of I researchers have already studied the NanoGripper’s ability to detect hepatitis B and plan to publish findings soon, Wang told The Pathologist. He also noted it’s possible the NanoGripper “can be integrated with a lateral flow assay paper strip platform for development of a rapid, sensitive, and inexpensive at home or point-of-care virus detection.”
There is “power in soft nanorobotics,” said Wang, who envisions potential for the NanoGripper beyond viruses to include programming the fingers to detect cancer markers and enabling the grippers to deliver treatment to target cells.
Clinical pathologists and laboratory managers may want to follow this research coming out of the University of Illinois Urbana-Champaign. Once put through additional clinical studies, such nanorobotic diagnostic technology might eventually be used at the point-of-care to help prevent viral infection and spread of disease.
