Clinical laboratory managers should prepare for an increase in demand for measles testing, especially for children
Clinical laboratory managers should be on the alert for new cases of measles. The US Centers for Disease Control and Prevention (CDC) has reported a surge in the highly infectious disease. Public health experts pointed to declining vaccination coverage as the primary cause. Officials in other countries have also reported outbreaks.
In 2000, the US declared that measles had been eliminated, meaning it “is no longer constantly present in this country,” the CDC stated on its website. However, the agency noted travelers can still bring the disease into the country and that there have been sporadic outbreaks since then.
In a new study, published April 11, 2024, in the CDC’s Morbidity and Mortality Weekly Report (MMWR), the agency reported that it was notified of 97 confirmed cases in the first quarter of 2024. That compares to an average of five cases during the first quarters of 2020 through 2023, the agency stated. In total, 338 cases were reported to the CDC between Jan. 1, 2020, and March 28, 2024, so the latest outbreaks amount to 29%—nearly a third—of the total.
“While the risk for measles for the majority of the US population still remains low, it’s crucial that we take the necessary steps now to prevent the continued spread of measles and maintain elimination in the US,” Adria D. Mathis, MSPH, lead author of the CDC report, told Healthline. Mathis is affiliated with the CDC’s Division of Viral Diseases at the National Center for Immunization and Respiratory Diseases (NCIRD).
“We have seen, in the region, not only a 30-fold increase in measles cases, but also nearly 21,000 hospitalizations and five measles-related deaths. This is concerning,” Hans Henri P. Kluge, MD (above), WHO Regional Director for Europe, told BBC News. “Vaccination is the only way to protect children from this potentially dangerous disease.” Clinical laboratories in the US that identify a case of measles from a positive test must report that result to public health labs. Thus, wise lab managers will track the rise in measles cases and prepare for increased demand for measles testing. (Photo copyright: World Health Organization.)
Renewed Threat to the US, Other Countries
The recent cases “represent a renewed threat to the US elimination status,” and “underscore the need for additional efforts to increase measles, mumps, and rubella (MMR) vaccination coverage, especially among close-knit and under-vaccinated communities,” Mathis told Healthline.
The MMWR report notes that most of the new cases were in persons under age 20, and that almost all were “in persons who were unvaccinated or whose vaccination status was unknown.” Most of the importations, the report states, were “among persons traveling to and from countries in the Eastern Mediterranean and African WHO [World Health Organization] regions; these regions experienced the highest reported measles incidence among all WHO regions during 2021–2022.”
In the US, vaccination coverage has been below 95% for three consecutive years. That is the “estimated population-level immunity necessary to prevent sustained measles transmission,” according to the federal agency. In 12 states and the District of Columbia, the coverage rate is below 90%. In total, “approximately 250,000 kindergarten children [are] susceptible to measles each year,” the CDC report states.
Measles vaccination coverage has declined globally, “from 86% in 2019 to 83% in 2022.” This left nearly 22 million children under the age of one susceptible to the disease, the report notes.
Earlier Measles Outbreaks in the US
The CDC performed its latest analysis following two larger measles outbreaks in 2019 among under-vaccinated populations in New York state.
The Associated Press (AP) reported that the 2019 epidemic, which totaled 1,274 cases nationwide, “was the worst in almost three decades and threatened the United States’ status as a country that has eliminated measles by stopping the continual spread of the measles virus.”
A vaccine for the disease first became available in 1963. Prior to its availability, “there were some three million to four million cases per year,” AP reported. Most people recover, but “in the decade before the vaccine was available, 48,000 people were hospitalized per year. … About 1,000 people developed dangerous brain inflammation from measles each year, and 400 to 500 died,” AP noted, citing CDC data.
US Not Alone in Fight against Measles
Other countries also are reporting spikes in measles cases. In a recently published rapid risk assessment, the Canadian government reported a total of 29 cases as of March 15, 2024, of which 21 were reported since Feb. 28.
“That’s already the largest annual total since 2019 and more than double the number of cases reported last year, as medical experts fear the number will rise while more Canadians travel in and out of the country this month for March break,” CBC News reported.
“New projections from a team at Simon Fraser University (SFU) in British Columbia show the grim possibilities,” CBC News reported. “The modelling suggests that vaccine coverage of less than 85% can lead to dozens of cases within small communities—or even hundreds if immunization rates are lower.”
Numbers are far worse in parts of Europe. In a February 2024 news release, the World Health Organization reported that in 2023, more than 58,000 people in its European region were infected by the disease, “resulting in thousands of hospitalizations and 10 measles-related deaths.”
According to WHO epidemiological data, countries in Central Asia, which is part of WHO’s European region, reported some of the highest numbers:
15,111 in Kazakhstan,
13,735 in Azerbaijan, and
7,044 in Kyrgyzstan.
The Russian Federation reported 12,723 cases and Turkey reported 4,559.
A WHO European Region Measles and Rubella Monthly Update notes that more than half of the regionwide cases—31,428—were reported in the last three months of 2023. More than 15,000 cases were reported in December. That compares to just 163 cases reported in 2021 and 942 in 2022. Nearly half of the cases were among children under the age of five.
Lack of Vaccinations among Children Blamed for Outbreaks
One factor that has led to the increase in measles cases was the disruption to immunization services caused by the COVID-19 pandemic. “This has resulted in a significant accumulation of susceptible children who have missed their routine vaccinations against measles and other vaccine-preventable diseases,” the WHO reported.
Among the region’s 53 member states, 33 had eliminated measles, WHO reported, but “this achievement remains fragile. To retain this status, a country must ensure that transmission of the virus following any importation is stopped within 12 months from the first reported case.”
In the UK, which reported 231 cases last year, the National Health Service has launched a campaign to improve vaccination rates, the BBC reported, noting that “more than 3.4 million children aged under 16 are unprotected and at risk of becoming ill.”
However, a public health campaign built on vaccination is successful only if a high rate of individuals get vaccinated. The Baby Boomer and Gen X generations had high rates of vaccination for smallpox, polio, etc. because the parents saw individuals in their family and neighborhood who became infected and suffered lifechanging consequences. They recognized that vaccination was a simple thing to provide protection from a potentially deadly infection.
Clinical laboratory managers and pathologists will want to follow the CDC’s ongoing reports of the number of cases of measles in this country. Today, the absolute number of new measles cases is relatively small. At the same time, in communities experiencing an outbreak of even a few measles cases, physicians may want to increase the volume of measles tests they order for their patients.
HHS Office of Inspector General was the latest to examine the quality control problems that led to distribution of inaccurate test to clinical laboratories nationwide
Failure on the part of the Centers for Disease Control and Prevention (CDC) to produce accurate, dependable SARS-CoV-2 clinical laboratory test kits at the start of the COVID-19 pandemic continues to draw scrutiny and criticism of the actions taken by the federal agency.
In the early weeks of the COVID-19 pandemic, the CDC distributed faulty SARS-CoV-2 test kits to public health laboratories (PHLs), delaying the response to the outbreak at a critical juncture. That failure was widely publicized at the time. But within the past year, two reports have provided a more detailed look at the shortcomings that led to the snafu.
“We identified weaknesses in CDC’s COVID-19 test kit development processes and the agencywide laboratory quality processes that may have contributed to the failure of the initial COVID-19 test kits,” the OIG stated in its report.
Prior to the outbreak, the agency had internal documents that were supposed to provide guidance for how to respond to public health emergencies. However, “these documents do not address the development of a test kit,” the OIG stated.
“If the CDC can’t change, [its] importance in health in the nation will decline,” said microbiologist Jill Taylor, PhD (above), Senior Adviser for the Association of Public Health Laboratories in Washington, DC. “The coordination of public health emergency responses in the nation will be worse off.” Clinical laboratories that were blocked from developing their own SARS-CoV-2 test during the pandemic would certainly agree. (Photo copyright: Columbia University.)
Problems at the CDC’s RVD Lab
Much of the OIG’s report focused on the CDC’s Respiratory Virus Diagnostic (RVD) lab which was part of the CDC’s National Center for Immunization and Respiratory Diseases (NCIRD). The RVD lab had primary responsibility for developing, producing, and distributing the test kits. Because it was focused on research, it “was not set up to develop and manufacture test kits and therefore had no policies and procedures for developing and manufacturing test kits,” the report stated.
The RVD lab also lacked the staff and funding to handle test kit development in a public health emergency, the report stated. As a result, “the lead scientist not only managed but also participated in all test kit development processes,” the report stated. “In addition, when the initial test kit failed at some PHLs, the lead scientist was also responsible for troubleshooting and correcting the problem.”
To verify the test kit, the RVD lab needed samples of viral material from the agency’s Biotechnology Core Facility Branch (BCFB) CORE Lab, which also manufactured reagents for the kit.
“RVD Lab, which was under pressure to quickly create a test kit for the emerging health threat, insisted that CORE Lab deviate from its usual practices of segregating these two activities and fulfill orders for both reagents and viral material,” the report stated.
This increased the risk of contamination, the report said. An analysis by CDC scientists “did not determine whether a process error or contamination was at fault for the test kit failure; however, based on our interviews with CDC personnel, contamination could not be ruled out,” the report stated.
The report also cited the CDC’s lack of standardized systems for quality control and management of laboratory documents. Labs involved in test kit development used two different incompatible systems for tracking and managing documents, “resulting in staff being unable to distinguish between draft, obsolete, and current versions of laboratory procedures and forms.”
Outside Experts Weigh In
The OIG report followed an earlier review by the CDC’s Laboratory Workgroup (LW), which consists of 12 outside experts, including academics, clinical laboratory directors, state public health laboratory directors, and a science advisor from the Association of Public Health Laboratories. Members were appointed by the CDC Advisory Committee to the Director.
This group cited four major issues:
Lack of adequate planning: For the “rapid development, validation, manufacture, and distribution of a test for a novel pathogen.”
Ineffective governance: Three labs—the RVD Lab, CORE Lab, and Reagent and Diagnostic Services Branch—were involved in test kit development and manufacturing. “At no point, however, were these three laboratories brought together under unified leadership to develop the SARS-CoV-2 test,” the report stated.
Poor quality control and oversight: “Essentially, at the start of the pandemic, infectious disease clinical laboratories at CDC were not held to the same quality and regulatory standards that equivalent high-complexity public health, clinical and commercial reference laboratories in the United States are held,” the report stated.
Poor test design processes: The report noted that the test kit had three probes designed to bind to different parts of the SARS-CoV-2 nucleocapsid gene. The first two—N1 (topology) and N2 (intracellular localization)—were designed to match SARS-CoV-2 specifically, whereas the third—N3 (functions of the protein)—was designed to match all Sarbecoviruses, the family that includes SARS-CoV-2 as well as the coronavirus responsible for the 2002-2004 SARS outbreak.
The N1 probe was found to be contaminated, the group’s report stated, while the N3 probe was poorly designed. The report questioned the decision to include the N3 probe, which was not included in European tests.
Also lacking were “clearly defined pass/fail threshold criteria for test validation,” the report stated.
Advice to the CDC
Both reports made recommendations for changes at the CDC, but the LW’s were more far-reaching. For example, it advised the agency to establish a senior leader position “with major responsibility and authority for laboratories at the agency.” This individual would oversee a new Center that would “focus on clinical laboratory quality, laboratory safety, workforce training, readiness and response, and manufacturing.”
In addition, the CDC should consolidate its clinical diagnostic laboratories, the report advised, and “laboratories that follow a clinical quality management system should have separate technical staff and space from those that do not follow such a system, such as certain research laboratories.”
The report also called for collaboration with “high functioning public health laboratories, hospital and academic laboratories, and commercial reference laboratories.” For example, collaborating on test design and development “should eliminate the risk of a single point of failure for test design and validation,” the LW suggested.
CBS News reported in August that the CDC had already begun implementing some of the group’s suggestions, including agencywide quality standards and better coordination with state labs.
However, “recommendations for the agency to physically separate its clinical laboratories from its research laboratories, or to train researchers to uphold new quality standards, will be heavy lifts because they require continuous funding,” CBS News reported, citing an interview with Jim Pirkle, MD, PhD, Director, Division of Laboratory Sciences, National Center for Environmental Health, at the CDC.
Some healthcare experts point to an “immunity gap” tied to the COVID-19 pandemic, while others suggest alternative theories such as temporary immunodeficiency brought on by COVID-19. In most cases, RSV causes “mild, cold-like symptoms,” but the CDC states it also can cause serious illness, especially for infants, young children, and older adults, leading to emergency room visits, hospitalizations, and an increased demand for clinical laboratory testing.
Pulmonology Advisor reported that the disease typically peaks between December and February, but hospitalizations this season hit their peak in November with numbers far higher than in previous years. In addition to infants and older adults, children between five and 17 years of age were “being hospitalized far in excess of their numbers in previous seasons,” the publication reported.
“Age by itself is a risk factor for more severe disease, meaning that the younger babies are usually the ones that are sick-sick,” pediatrician Asuncion Mejias, MD, PhD (above), a principal investigator with the Center for Vaccines and Immunity at Nationwide Children’s Hospital in Columbus, Ohio, told MarketWatch. Now, she added, “we are also seeing older kids, probably because they were not exposed to RSV the previous season.” Clinical laboratories in hospitals caught the brunt of those RSV inpatient admissions. (Photo copyright: Nationwide Children’s Hospital.)
Did COVID-19 Cause Immunity Gap and Surge in Respiratory Diseases?
CDC data shows that hospitalization rates linked to RSV have steadily declined since hitting their peak of 5.2 per 100,000 people in mid-November. In contrast, hospitalizations linked to the flu peaked in late November and early December at 8.7 per 100,000. Hospitalizations linked to COVID 19—which still exceed those of the other respiratory diseases—reached a plateau of 9.7 per 100,000 in early December, then saw an uptick later that month before declining in the early part of January, 2023, according to the CDC’s Respiratory Virus Hospitalization Surveillance Network (RESP-NET) dashboard.
Surveillance by the CDC’s National Center for Immunization and Respiratory Diseases (NCIRD) revealed a similar pattern: An early peak in weekly numbers for emergency room visits for RSV, followed by a spike for influenza and steadier numbers for COVID-19.
So, why was the RSV outbreak so severe?
Respiratory diseases tend to hit hardest in winter months when people are more likely to gather indoors. Beyond that, some experts have cited social distancing and masking requirements imposed in 2020 and 2021 to limit the spread of COVID 19. These measures, along with school closures, had the side effect of reducing exposure to influenza and RSV.
“It’s what’s being referred to as this ‘immunity gap’ that people have experienced from not having been exposed to our typical respiratory viruses for the last couple of years, combined with reintroduction to indoor gatherings, indoor venues, indoor school, and day care without any of the mitigation measures that we had in place for the last couple of years,” infectious disease expert Kristin Moffitt, MD, of Boston Children’s Hospital told NPR.
Term ‘Immunity Debt’ Sparks Controversy
Other experts have pushed back against the notion that pandemic-related public health measures are largely to blame for the RSV upsurge. Many have objected to the term “immunity debt,” a term Forbes reported on in November.
“Immunity debt is a made-up term that did not exist until last year,” pediatrician Dave Stukus, MD, wrote on Twitter. Stukus is a Professor of Clinical Pediatrics in the Division of Allergy and Immunology at Nationwide Children’s Hospital in Columbus, Ohio.
An article published by Texas Public Radio (TPR) suggests further grounds for skepticism, stating that “the immunity debt theory doesn’t seem to hold up to scrutiny.”
“That was sort of the great unmasking, and everybody got viral illnesses,” she told TPR. “Now we’re past that. We’ve already been through that. We should have some immunity from that and we’re having it again.”
She added that “the hospital is filled with babies who are less than a year of age who have RSV infection. Those children weren’t locked down in 2020.”
The story also noted that not all Americans complied with social distancing or masking guidelines.
“We’re not seeing [less viral illness in] states in the United States that were less strict compared to states that were stricter during mask mandates and things like that. All the states are being impacted,” Barton told TPR.
Perfect Storm of Demand for Clinical Laboratory Testing
Barton suggested that COVID-19 might have compromised people’s immune systems in ways that made them more susceptible to other respiratory diseases. For example, a study published in Nature Immunology, titled, “Immunological Dysfunction Persists for Eight Months following Initial Mild-to-Moderate SARS-CoV-2 Infection,” found that some patients who survived COVID-19 infection developed post-acute long COVID (LC, aka, COVID syndrome) which lasted longer than 12 weeks. And that “patients with LC had highly activated innate immune cells, lacked naive T and naive B cells, and showed elevated expression of type I IFN (IFN-β) and type III IFN (IFN-λ1) that remained persistently high at eight months after infection.”
Experts speaking to The Boston Globe said that multiple factors are likely to blame for the severity and early arrival of the RSV outbreak. Pediatric hospitalist and infectious disease specialist Chadi El Saleeby, MD, of Massachusetts General Hospital, said the severity of some cases might be tied to simultaneous infection with multiple viruses.
Clinical laboratories experienced a perfect storm of infectious disease testing demands during this tripledemic. Hopefully, with the arrival of spring and summer, that demand for lab tests will wane and allow for a return to a normal rate of traditional laboratory testing.
At present, medical laboratories are collecting blood specimens for testing by authorized public health labs. However, clinical laboratories should prepare for the likelihood they will be called on to perform the testing using the CDC test or other tests under development.
“We need to be vigilant and understand everything related to the testing and the virus,” said Bodhraj Acharya, PhD, Manager of Chemistry and Referral Testing at the Laboratory Alliance of Central New York, in an exclusive interview with Dark Daily. “If the situation comes that you have to do the testing, you have to be ready for it.”
The current criteria for determining PUIs include clinical features, such as fever or signs of lower respiratory illness, combined with epidemiological risks, such as recent travel to China or close contact with a laboratory-confirmed COVID-19 patient. The CDC notes that “criteria are subject to change as additional information becomes available” and advises healthcare providers to consult with state or local health departments if they believe a patient meets the criteria.
Bodhraj Acharya, PhD (above), is Manager of Chemistry and Referral Testing at the Laboratory Alliance of Central New York. In an exclusive interview with Dark Daily, he stressed the importance that medical laboratories be prepared. “We need to be vigilant and be active and understand everything related to this virus and the testing. That’s the role of clinical laboratory scientists, to be ready because this can become a pandemic anytime. It can spread and tomorrow the CDC could announce it is disseminating the test to designated laboratories.” (Photo copyright: Laboratory Alliance of Central New York.)
Test Kit Problems Delay Diagnoses
On Feb. 4, the FDA issued a Novel Coronavirus Emergency Use Authorization (EUA) allowing state and city public health laboratories, as well as Department of Defense (DoD) labs, to perform presumptive qualitative testing using the Real-Time Reverse Transcriptase PCR (RT-PCR) diagnostic panel developed by the CDC. Two days later, the CDC began distributing the test kits, a CDC statement announced. Each kit could test 700 to 800 patients, the CDC said, and could provide results from respiratory specimens in four hours.
However, on Feb. 12, the agency revealed in a telebriefing that manufacturing problems with one of the reagents had caused state laboratories to get “inconclusive laboratory results” when performing the test.
“When the state receives these test kits, their procedure is to do quality control themselves in their own laboratories,” said Nancy Messonnier, MD, Director of the CDC National Center for Immunization and Respiratory Diseases (NCIRD), during the telebriefing. “Again, that is part of the normal procedures, but in doing it, some of the states identified some inconclusive laboratory results. We are working closely with them to correct the issues and as we’ve said all along, speed is important, but equally or more important in this situation is making sure that the laboratory results are correct.”
During a follow-up telebriefing on Feb. 14, Messonnier said
that the CDC “is reformulating those reagents, and we are moving quickly to get
those back out to our labs at the state and local public health labs.”
Above is a picture of CDC’s laboratory test kit for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). CDC is shipping the test kits to laboratories CDC has designated as qualified, including US state and local public health laboratories, Department of Defense (DOD) laboratories, and select international laboratories. The test kits are bolstering global laboratory capacity for detecting SARS-CoV-2. (Photo and caption copyright: Centers for Disease Control and Prevention.)
Serologic Test Under Development
The current test has to be performed after a patient shows
symptoms. The “outer bound” of the virus’ incubation period is 14 days, meaning
“we expect someone who is infected to have symptoms some time during those 14
days,” Messonnier said. Testing too early could “produce a negative result,”
she continued, because “the virus hasn’t established itself sufficiently in the
system to be detected.”
Messonnier added that the agency plans to develop a serologic test that will identify people who were exposed to the virus and developed an immune response without getting sick. This will help determine how widespread it is and whether people are “seroconverting,” she said. To formulate this test, “we need to wait to draw specimens from US patients over a period of time. Once they have all of the appropriate specimens collected, I understand that it’s a matter of several weeks” before the serologic test will be ready, she concluded.
“Based on what we know now, we believe this virus spreads
mainly from person to person among close contacts, which is defined [as] about
six feet,” Messonnier said at the follow-up telebriefing. Transmission is
primarily “through respiratory droplets produced when an infected person coughs
or sneezes. People are thought to be the most contagious when they’re most
symptomatic. That’s when they’re the sickest.” However, “some spread may happen
before people show symptoms,” she said.
The virus can also spread when people touch contaminated surfaces and then touch their eyes, nose, or mouth. But it “does not last long on surfaces,” she said.
Where the Infection Began
SARS-CoV-2 was first identified during an outbreak in Wuhan, China, in December 2019. Soon thereafter, hospitals in the region “were overwhelmed” with cases of pneumonia, Dr. Acharya explained, but authorities could not trace the disease to a known pathogen. “Every time a new pathogen originates, or a current pathogen mutates into a new form, there are no molecular tests available to diagnose it,” he said.
So, genetic laboratories used next-generation sequencing, specifically unbiased nontargeted metagenomic RNA sequencing (UMERS), followed by phylogenetic analysis of nucleic acids derived from the hosts. “This approach does not require a prior knowledge of the expected pathogen,” Dr. Acharya explained. Instead, by understanding the virus’ genetic makeup, pathology laboratories could see how closely it was related to other known pathogens. They were able to identify it as a Betacoronavirus (Beta-CoVs), the family that also includes the viruses that cause SARS and Middle East Respiratory Syndrome (MERS).
This is a fast-moving story and medical laboratory leaders are advised to monitor the CDC website for continuing updates, as well as a website set up by WHO to provide technical guidance for labs.
