Though not a replacement for clinical laboratory testing, the CDC says the surveillance system will help slow spread of COVID-19 in vulnerable communities
Clinical laboratory testing for COVID-19 is receiving an ally. In mid-August, the Centers for Disease Control and Prevention (CDC) and the US Department of Health and Human Services (HHS) announced they were initiating a National Wastewater Surveillance System (NWSS) in response to the COVID-19 pandemic.
In collaboration with other federal agencies, the NWSS will work with state, local, territorial, and tribal health departments to collect data on wastewater (aka, sewage) samples throughout the United States.
The goal of the NWSS is to detect SARS-CoV-2, the coronavirus that causes COVID-19, before it spreads by detecting traces of it in local sewer systems. The level of the virus detected in wastewater can be a leading indicator of a worsening outbreak in a community, according to a CDC statement.
“Quantitative SARS-CoV-2 measurements in untreated sewage can provide information on changes in total COVID-19 infection in the community contributing to that wastewater treatment plant,” noted the CDC.
People infected with the coronavirus discard traces of it—whether they are symptomatic or asymptomatic—and levels of the virus in untreated sewage can provide scientists with information about the degree of outbreak in specific areas.
The NWSS will not include or monitor homes that use septic tanks or entities with decentralized systems that treat their own waste, such as hospitals, universities, and prisons.
Not a Replacement for Clinical Laboratory Testing
The CDC stressed that sewage testing is not meant to replace clinical laboratory testing, but it can be a valuable tool in communities where COVID-19 tests are underutilized or unavailable. Wastewater testing, CDC noted in its statement, could have an enormous reach as 80% of households in the US are connected to a municipal sewage system.
The CDC is not actively taking samples from wastewater, but relying on local partners to take samples, test them, and enter data into the NWSS portal for the purpose of summarizing and interpreting for public health action.
The agency predicts that participation in a national database will ensure data comparability across separate jurisdictions.
Could Testing Raw Sewage Be More Effective than Contact Tracing for Tracking COVID-19 Outbreaks?
A Yale University study published in Nature Biotechnology, titled, “Measurement of SARS-CoV-2 RNA in Wastewater Tracks Community Infection Dynamics,” detected SARS-CoV-2 concentrations in sewage sludge in New Haven, Conn., over a 10-week period earlier this year. The results of the study “show the utility of viral RNA monitoring in municipal wastewater for SARS-CoV-2 infection surveillance at a population-wide level,” the study authors noted.
The published study states that “SARS-CoV-2 RNA was detected throughout the more than 10-week study and, when adjusted for time lags, tracked the rise and fall of cases seen in SARS-CoV-2 clinical test results and local COVID-19 hospital admissions. Relative to these indicators, SARS-CoV-2 RNA concentrations in sludge were 0–2 [days] ahead of SARS-CoV-2 positive test results by date of specimen collection, 0–2 [days] ahead of the percentage of positive tests by date of specimen collection, 1–4 [days] ahead of local hospital admissions and 6–8 [days] ahead of SARS-CoV-2 positive test results by reporting date.”
The Yale researchers concluded, “Our results demonstrate that measurement of SARS-CoV-2 RNA concentrations in primary sludge provides an approach to estimate changes in COVID-19 prevalence on a population level. Sludge results were not a leading indicator compared to positive test results or percentage of positive tests by date of specimen collection. However, they led hospitalizations by 1–4 [days] and test results by report date by ~1 week. Thus, in communities where test reporting is delayed, sludge results, if analyzed and reported on the same day as sampling, can provide substantial advance notice of infection dynamics.”
Sewage Testing for COVID-19 Around the World
Sewage testing can provide data to complement other collected information about COVID-19 and steer public health decision-making. However, the CDC notes that “it is not possible to reliably and accurately predict the number of infected individuals in a community based on sewage testing” and that “more data on fecal shedding by infected individuals over the course of disease are needed to better understand the limits of detection.”
Nevertheless, some experts have leaned heavily on sewage sample testing for their conclusions about the origination of the coronavirus. In August, Dark Daily reported on a theory based on finding remnants of SARS-CoV-2 in sewage systems that suggested the virus may not have originated in Wuhan, China. Analysis of sewage samples in Italy, Spain, and Brazil indicated the virus was present in those countries before the disease was known to exist outside of China. The controversy over these findings has motivated virologists to expand wastewater testing.
The creation of the NWSS by the CDC validates growing interest in new methods of testing for infectious disease. Lower cost, faster response time, more automation of genetic sequencing, and improved analytical software has enabled this type of testing to become a useful tool. It would be wise for clinical laboratory managers to monitor the expanded use of new testing technologies for infectious diseases.
Understanding how superspreading occurs can help clinical lab leaders slow and even prevent the spread of SARS-CoV-2 within their communities and health systems
Clinical laboratories understand the critical importance of preventing the spread of infection. However, according to the Boston Globe, researchers worldwide are learning that roughly 80% of new COVID-19 cases are caused by just 10% of infected people. Those people are called superspreaders.
It’s critical that medical laboratory managers are aware of the role superspreaders play in transmitting SARS-CoV-2, the coronavirus that causes the COVID-19 illness.
Clinical lab leaders who understand how superspreading occurs can take steps to protect staff, patients, and anyone who visits the facility. Because lab personnel such as couriers and phlebotomists, among others, come into contact with large numbers of people daily, understanding how to identify superspreaders could limit transmissions of the coronavirus within the laboratory, as well as within hospital networks.
Superspreading versus Plodding
Influenza and other viruses tend to spread in a way that epidemiologists call “plodding.” One person infects another, and the virus slowly spreads throughout the population. However, scientists around the globe are finding that SARS-CoV-2 transmission does not fit that pattern. Instead, a few infected people appear to be transmitting the virus to dozens of other people in superspreading events, Boston Globe reported.
“You can think about throwing a match at kindling. You throw one match, it might not light the kindling. You throw another match, it may not light the kindling. But then one match hits the right spot and all of a sudden the fire goes up,” Ben Althouse, PhD, principal scientist and co-chair of epidemiology at the Institute for Disease Modeling in Bellevue, Wash., told the Boston Globe.
But because roughly 90% of infected people aren’t spreading the virus, identifying who the superspreaders are can be a challenge. Nevertheless, limiting situations in which superspreading is likely to occur could greatly reduce the spread of infection.
Examples of Superspreading Events
One of the first big outbreaks in the United States was an example of a superspreading event. The Biogen (NASDAQ:BIIB) leadership conference in late February in Boston resulted in at least 99 cases of COVID-19 just in Massachusetts, reported the Boston Globe.
Several superspreading events have occurred in houses of worship. One well-documented example prompted a CDC Morbidity and Mortality Weekly Report, titled, “High SARS-CoV-2 Attack Rate Following Exposure at a Choir Practice—Skagit County, Washington.” The 122-member choir met for practice twice in March. On March 3 no one had symptoms, but one person had cold-like symptoms at the March 10 practice. Eventually, 53 members tested positive for SARS-CoV-2.
On May 30, a Texas family held a birthday party, Medical Xpress reported. Twenty-five people attended the party, which only lasted a few hours. The family followed the state’s guidelines for gatherings, however one of the hosts was infected with the SARS-CoV-2 coronavirus and wasn’t aware of it. Seven attendees contracted it, and those seven spread the virus to an additional 10 family members. A total of 18 members of a single family were infected.
There are commonalities among the documented superspreading events. Most occur indoors, often in poorly ventilated areas. Some activities cause more respiratory droplets to be expelled than others, such as singing. Some respiratory droplets are released simply by breathing, and many more are expelled when a person talks. Talking louder expels even more droplets into the air.
Are Some People More Likely to Spread the Coronavirus than Others?
The fact that so few people are responsible for the majority of transmissions of the virus raises questions. Do some people simply have more virus particles to shed? Is biology a factor?
One factor may be how long the SARS-CoV-2 coronavirus is in the body before symptoms of the COVID-19 illness manifest.
“If people got sick right away after they were infected, they might stay at home in bed, giving them few opportunities to transmit the virus,” noted Scientific American in “How ‘Superspreading’ Events Drive Most COVID-19 Spread.” However, CDC states on its website that “The incubation period for COVID-19 is thought to extend to 14 days, with a median time of 4-5 days from exposure to symptoms onset. One study reported that 97.5% of persons with COVID-19 who develop symptoms will do so within 11.5 days of SARS-CoV-2 infection.”
During that time, infected individuals may transmit the virus to dozens of other people. The CDC estimates that about 40% of transmission occurs in pre-symptomatic people, Scientific American reported.
But it’s not all bad news. The fact that circumstances may be more important than biology might be good news for clinical laboratories. “Knowing that COVID-19 is a superspreading pandemic could be a good thing. It bodes well for control,” Nelson told the Boston Globe.
Clinical laboratory managers are encouraged to follow CDC recommended safety protocols, titled, “Guidance for General Laboratory Safety Practices during the COVID-19 Pandemic.” They include social distancing, setting up one-way paths through lab areas, sanitizing shared surfaces such as counters and benchtops, and implementing flexible leave policies so that sick employees can stay home.
Following these guidelines, and being aware of superspreaders, can help medical laboratories and anatomic pathology groups keep staff and customers free of infection.
Privacy concerns have one tech giant suggesting alternatives to sharing potentially identifiable location tracking data
Expect an interesting debate on the use of location tracking as a way to manage this and future pandemics. It is a debate that has implications for clinical laboratories. After all, if location tracking identifies individuals who may have been exposed to an infectious disease, will health authorities want those individuals to be immediately tested?
Location tracking has been around for quite some time. Anyone who owns a smartphone knows that digital map and navigation software applications (apps) locate our position and track our movements. That’s how they work. Maps are good. But does collecting and sharing location tracking data violate personal privacy laws that some Silicon Valley tech giants want to use to help public health officials track disease? Maybe.
Google, Facebook, and other tech companies have been talking to the US federal government about ways to use location tracking data from smartphones and online software applications to combat the spread of SARS-CoV-2, the coronavirus that causes the COVID-19 illness, reported the Washington Post.
The tracking data could be used by public health officials
to spot disease outbreaks in populations and predict how it might spread. Analyzing
the data generated by smartphone tracking and reporting apps also could be used
to identify individuals who may have been exposed to the coronavirus, and who should
get clinical laboratory tests to determine if they need medical intervention.
However, Google is apparently resistant to using its collected location data to track and identify individuals. Instead, Google Health’s Head of Communications and Public Affairs, Johnny Luu, said Google was “exploring ways that aggregated anonymized location information could help in the fight against COVID-19. One example could be helping health authorities determine the impact of social distancing, similar to the way we show popular restaurant times and traffic patterns in Google Maps,” said Luu in a statement. He stressed, though, that any such arrangement “would not involve sharing data about any individual’s location, movement, or contacts,” reported the Washington Post.
Can Privacy be Maintained While Tracking Disease?
Google’s sister company, Verily, launched a screening website in March for people who believe they may have COVID-19. The pilot program is only available to some California residents. Users of the service complete a series of online questions to determine their coronavirus risk and whether or not they should seek medical attention.
To use the service, individuals must log into the site using
a Google account and sign a consent authorization form which states data
collected may be shared with public health officials, a move that has received
criticism.
Jacob Snow, JD, a technology and civil liberties attorney with the American Civil Liberties Union (ACLU) of Northern California, expressed concerns about Verily’s program. “COVID-19 testing is a vital public necessity right now—a core imperative for slowing this disease,” he told CNET. “Access to critical testing should not depend on creating an account and sharing information with what is, essentially, an advertising company.
“This is how privacy invasions have the potential to
disproportionately harm the vulnerable,” he continued. “Google should release
this tool without those limits, so testing can proceed as quickly as possible.”
Facebook, on the other hand, has had a Disease Prevention Map program in place for about a year. This program provides location information provided by individuals who choose to participate to health organizations around the globe.
“Disease prevention maps have helped organizations respond to health emergencies for nearly a year and we’ve heard from a number of governments that they’re supportive of this work,” said Laura McGorman, Policy Lead, Data for Good at Facebook, in a statement, reported CNET. “In the coronavirus context, researchers and nonprofits can use the maps, which are built with aggregated and anonymized data that people opt in to share, to understand and help combat the spread of the virus.”
Privacy Organizations Voice Concerns
Privacy and civil liberties issues regarding the collection
and use of smartphone data to curtail the pandemic are of concern to some organizations.
There may be legal and ethical implications present when using personal data in
this manner.
Al Gidari, JD, Director of Privacy, Center for Internet and Society at Stanford University Law School, says the balance between privacy and pandemic policy is a delicate one, reported the Washington Post. “The problem here is that this is not a law school exam. Technology can save lives, but if the implementation unreasonably threatens privacy, more lives may be at risk,” he said.
In response to public privacy concerns following the Washington
Post’s report, representatives for Google and Facebook said the companies
have not shared any aggregated and anonymized data with the government
regarding contact
tracing and COVID-19, reported the Washington Post.
Google reiterated that any related projects are still in their early stages and that they are not sure what their participation level might look like. And, CEO Mark Zuckerberg stated that Facebook “isn’t prepared to turn over people’s location data en masse to any governments for tracking the coronavirus outbreak,” reported CNET.
“I don’t think it would make sense to share people’s data in a way where they didn’t have the opportunity to opt in to do that,” Zuckerberg said.
The potential use of location tracking data, when combined
with other information, is one example of how technology can leverage non-medical
information and match it with clinical data to watch population trends.
As of April 23, there were 2,637,911 confirmed cases of COVID-19 and 184,235 deaths from the coronavirus worldwide, according to www.worldometers.info/coronavirus. And, cases of coronavirus disease have been reported in 213 countries according to the World Health Organization (WHO).
As testing increases, more cases will be reported and it is
unknown how long the virus will continue to spread, so advocates of location
tracking and similar technologies that can be brought to bear to save lives during
a disease outbreak may be worth some loss of privacy.
Pathologists and medical laboratory professionals may want
to monitor the public debate over the appropriate use of location tracking.
After all, at some future point, clinical laboratory test results of
individuals might be added to location tracking programs to help public health
authorities better monitor where disease outbreaks are occurring and how they are
spreading.
Media reports in the United Kingdom cite bad timing and centralization of public health laboratories as reasons the UK is struggling to meet testing goals
Clinical pathologists and medical laboratories in UK and the US function within radically different healthcare systems. However, both countries faced similar problems deploying widespread diagnostic testing for SARS-CoV-2, the novel coronavirus that causes COVID-19. And the differences between America’s private healthcare system and the UK’s government-run, single-payer system are exacerbating the UK’s difficulties expanding coronavirus testing to its citizens.
The Dark Daily reported in March that a manufacturing snafu had delayed distribution of a CDC-developed diagnostic test to public health laboratories. This meant virtually all testing had to be performed at the CDC, which further slowed testing. Only later that month was the US able to significantly ramp up its testing capacity, according to data from the COVID Tracking Project.
However, the UK has fared even worse, trailing Germany, the US, and other countries, according to reports in Buzzfeed and other media outlets. On March 11, the UK government established a goal of administering 10,000 COVID-19 tests per day by late March, but fell far short of that mark, The Guardian reported. The UK government now aims to increase this to 25,000 tests per day by late April.
This compares with about 70,000 COVID-19 tests per day in
Germany, the Guardian reported, and about 130,000 per day in the US
(between March 26 and April 14), according to the COVID Tracking Project.
What’s Behind the UK’s Lackluster COVID-19 Testing
Response
In January, when the outbreak first hit, Public Health England (PHE) “began a strict program of contact tracing and testing potential cases,” Buzzfeed reported. But due to limited medical laboratory capacity and low supplies of COVID-19 test kits, the government changed course and de-emphasized testing, instead focusing on increased ICU and ventilator capacity. (Scotland, Wales, and Northern Ireland each have separate public health agencies and national health services.)
Later, when the need for more COVID-19 testing became
apparent, UK pathology laboratories had to contend with global shortages of
testing kits and chemicals, The Guardian reported. At present, COVID-19 testing
is limited to healthcare workers and patients displaying symptoms of pneumonia,
acute
respiratory distress syndrome, or influenza-like illness, PHE stated in “COVID-19:
Investigation and Initial Clinical Management of Possible Cases” guidance.
Another factor that has limited widespread COVID-19 testing is the country’s highly-centralized system of public health laboratories, Buzzfeed reported. “This has limited its ability to scale and process results at the same speed as other countries, despite its efforts to ramp up capacity,” Buzzfeed reported. Public Health England, which initially performed COVID-19 testing at one lab, has expanded to 12 labs. NHS laboratories also are testing for the SARS-CoV-2 coronavirus, PHE stated in “COVID-19: How to Arrange Laboratory Testing” guidance.
Sharon Peacock, PhD, PHE’s National Infection Service Interim Director, Professor of Public Health and Microbiology at the University of Cambridge, and honorary consultant microbiologist at the Cambridge clinical and public health laboratory based at Addenbrookes Hospital, defended this approach at a March hearing of the Science and Technology Committee (Commons) in Parliament.
“Laboratories in this country have largely been merged, so we have a smaller number of larger [medical] laboratories,” she said. “The alternative is to have a single large testing site. From my perspective, it is more efficient to have a bigger testing site than dissipating our efforts into a lot of laboratories around the country.”
Writing in The Guardian, Paul Hunter, MB ChB MD, a microbiologist and Professor of Medicine at University of East Anglia, cites historic factors behind the testing issue. The public health labs, he explained, were established in 1946 as part of the National Health Service. At the time, they were part of the country’s defense against bacteriological warfare. They became part of the UK’s Health Protection Agency (now PHE) in 2003. “Many of the laboratories in the old network were shut down, taken over by local hospitals or merged into a smaller number of regional laboratories,” he wrote.
US Facing Different Clinical Laboratory Testing Problems
Meanwhile, a few medical laboratories in the US are now contending with a different problem: Unused testing capacity, Nature reported. For example, the Broad Institute of MIT and Harvard in Cambridge, Mass., can run up to 2,000 tests per day, “but we aren’t doing that many,” Stacey Gabriel, PhD, a human geneticist and Senior Director of the Genomics Platform at the Broad Institute, told Nature. Factors include supply shortages and incompatibility between electronic health record (EHR) systems at hospitals and academic labs, Nature reported.
Politico
cited the CDC’s narrow testing criteria, and a lack of supplies for collecting
and analyzing patient samples—such as swabs and personal protective equipment—as
reasons for the slowdown in testing at some clinical laboratories in the US.
Challenges Deploying Antibody Tests in UK
The UK has also had problems deploying serology tests designed to detect whether people have developed antibodies against the virus. In late March, Peacock told members of Parliament that at-home test kits for COVID-19 would be available to the public through Amazon and retail pharmacy chains, the Independent reported. And, Politico reported that the government had ordered 3.5 million at-home test kits for COVID-19.
However, researchers at the University of Oxford who had been charged with validating the accuracy of the kits, reported on April 5 that the tests had not performed well and did not meet criteria established by the UK Medicines and Healthcare products Regulatory Agency (MHRA). “We see many false negatives (tests where no antibody is detected despite the fact we know it is there), and we also see false positives,” wrote Professor Sir John Bell, GBE, FRS, Professor of Medicine at the university, in a blog post. No test [for COVID-19], he wrote, “has been acclaimed by health authorities as having the necessary characteristics for screening people accurately for protective immunity.”
He added that it would be “at least a month” before suppliers could develop an acceptable COVID-19 test.
In the United States, the Cellex COVID-19 test is intended for use by medical laboratories. As well, many research sites, academic medical centers, clinical laboratories, and in vitro diagnostics (IVD) companies in the US are working to develop and validate serological tests for COVID-19.
Within weeks, it is expected that a growing number of such
tests will qualify for a Food and Drug Administration (FDA) Emergency Use
Authorization (EUA) and become available for use in patient care.
Asian locales reacted swiftly to the threat of COVID-19 by leveraging lessons learned from previous pandemics and making use of serology testing in aggressive contact tracing
America’s healthcare leaders in government, hospitals, clinical pathology, and medical laboratories can learn important lessons from the swift responses to the early outbreaks of COVID-19 in countries like Taiwan and South Korea and in cities like Singapore and Hong Kong.
Strategies such as early intervention, commitment to tracing contacts of infected people within two hours, quarantines, and social distancing all contributed to significantly curtailing the spread of the latest coronavirus pandemic within their borders, The New York Times (NYT) reported.
Another response common to the efforts of these countries and cities was the speedy introduction of clinical laboratory tests for SARS-CoV-2, the novel coronavirus that causes coronavirus disease 2019 (COVID-19), supported by the testing of tens of thousands of people in the earliest stages of the outbreaks in their communities. And that preparation and experience is paying off as those countries and cities continue to address the spread of COVID-19.
‘We Look at SARS as the Dress Rehearsal’
“Maybe it’s because of our Asian context, but our community
is sort of primed for this. We will keep fighting, because isolation and
quarantine work,” Lalitha
Kurupatham, Deputy Director of the Communicable Diseases Division in
Singapore, told the NYT. “During peacetime, we plan for epidemics like
this.”
Clinical laboratory leaders and pathologists may recall that Hong Kong was the site of the 2003 severe acute respiratory syndrome (SARS) epidemic. About 8,096 people worldwide were infected, and 774 died from SARS, according to the World Health Organization (WHO). In Hong Kong, 299 died out of 1,755 cases. However, Singapore had just 238 cases and 33 deaths.
To what does Singapore attribute the country’s lower
COVID-19 infection/death rate today?
“We can look at SARS as the dress rehearsal. The experience was raw, and very, very visceral. And on the back of it, better systems were put in place,” Jeremy Lim, MD, Co-Director of the Leadership Institute for Global Health Transformation at the National University of Singapore, told TIME.
“It’s a mix of carrots and sticks that have so far helped us. The US should learn from Singapore’s response and then adapt what is useful,” Lim added.
Singapore Debuts Serology Testing for COVID-19 Tracking
As microbiologists and infectious diseases doctors know, serology tests work by identifying antibodies that are the sources of infection. In the case of COVID-19, these tests may have aided in the surveillance of people infected with the coronavirus.
This is one lesson the US is learning.
“CDC (Centers for Disease Control and Prevention) has developed two serological tests that we’re evaluating right now, so we can get an idea through surveillance what’s the extent of this outbreak and how many people really are infected,” Robert Redfield, MD, CDC Director, told STAT.
As of March 27, Singapore (located about 2,374 miles from
mainland China with a population of 5.7 million) had reported 732 COVID-19
cases and two deaths, while Hong Kong had reported 518 cases and four deaths.
According to Time, in its effort to battle and treat
COVID-19, Singapore took the following steps:
Clinical laboratory testing for COVID-19 of all
people presenting with “influenza-like” and pneumonia symptoms;
Contact tracing of each infected person,
including interviews, review of flight manifests, and police involvement;
Using locally developed test to find antibodies
after COVID-19 clears;
Ran ads on page one of newspapers urging people
with mild symptoms to see a doctor; and
Government paid $100 Singapore dollars per day to
quarantined self-employed people.
The Singapore government’s WhatsApp account shares updates on the coronavirus, and Singapore citizens acquire wearable stickers after having their temperature checked at building entrances, Wired reported. The article also noted teams of healthcare workers are kept separate in hospitals—just in case some workers have to be quarantined.
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Meanwhile, in Hong Kong, citizens donned face masks and
pressured the government to respond to the COVID-19 outbreak. Officials subsequently
tightened borders with mainland China and took other action, the NYT reported.
Once the COVID-19 genetic sequence became available, national medical laboratory networks in Singapore, Hong Kong, and Japan developed their own diagnostic tests, reported The Lancet, which noted that the countries also expanded capacity for testing and changed financing systems, so people would not have to pay for the tests. In Singapore, the government pays for hospitalization as well, noted The Lancet.
Lessons Learned
The US has far less experience with pandemics, as compared to the Asian locales that were affected by the H1N1 influenza (Spanish Flu) of 1918-1920 and the H5N1 influenza (Avian Flu) of 1957-1958.
And, controversially, National Security Council (NSC) officials in 2018 discontinued the federal US Pandemic Response Unit, moving the NSC employees into other government departments, Associated Press reported.
According to the March 26 US Coronavirus Task Force’s televised
news conference, 550,000 COVID-19 tests have been completed nationwide and
results suggest 86% of those tested are negative for the disease.
The fast-moving virus and rapidly developing story are placing
medical laboratory testing in the global spotlight. Pathologists and clinical laboratory
leaders have a unique opportunity to advance the profession, as well as improving
the diagnosis of COVID-19 and the health of patients.