Uncovering the value of syndromic testing for respiratory infections

Respiratory tract infections are a major burden on society, leading to more physician visits and absences from school and work compared to any other illness.¹ Many respiratory illnesses have highly similar symptoms, like cough or runny nose; however, each condition can be caused by different respiratory pathogens, which can make clinical diagnosis and appropriate treatment challenging. 

Diagnostic techniques that test for individual or a small number of respiratory pathogens may result in important infections being missed the first time and require further testing on patient samples in order to get to a diagnosis. These tests may also miss co-infections, which could potentially result in delays in appropriate patient management. Therefore, when you consider the way multiple respiratory pathogens can circulate throughout the year causing major strain on the healthcare system, there is a need for improved, comprehensive diagnostic techniques. 

Having rapid, actionable results are even more crucial for high-risk patients who may suffer from other comorbidities that can lead to other complications or hospitalization. This can include populations such as younger children, older adults, pregnant women, or immunocompromised individuals, like those with cancer or who have received transplants.²

To that end, lab leaders should consider incorporating syndromic testing for respiratory illnesses. Unlike conventional tests, these tests are designed to identify multiple respiratory pathogens within a single test, ensuring that patients receive the best possible care that can lead to the best possible outcomes.

Respiratory illnesses have similar clinical presentations, with a wide range of symptoms. However, the cause of each illness can be different, necessitating a rapid and reliable diagnosis to ensure patients receive the most appropriate therapy. While the viruses that cause the flu, respiratory syncytial virus (RSV), and COVID-19 are common, there are other viruses and even bacteria that all lead to very similar symptoms.

Worldwide, there are approximately 1 billion cases of influenza, with 3-5 million cases classed as severe. While vaccines are updated each season in an attempt to curb infections and the severity of symptoms, infections from the flu can still occur and lead to respiratory deaths up to 650,000 each year.³ Interestingly, studies have shown that the flu, which many individuals consider the most common respiratory pathogens, only accounts for a small percentage of respiratory illness.⁴  

Rapid testing can provide a prompt diagnosis to distinguish influenza from other respiratory pathogens, which can assist with administering antiviral treatment for influenza or lead to proper antiviral de-escalation when a patient is being preemptively treated and influenza is not the causative agent.⁵

COVID-19 is the disease caused by the SARS-CoV-2 virus. As of August 2023, there have been over 760 million cases of COVID-19 and 6.9 million deaths worldwide, according to the World Health Organization (WHO).⁶ As of June 2023, over 13 billion vaccine doses have been administered, and while these vaccines can help diminish hospitalization and death, infections can still occur.⁷ Furthermore, there are additional tools in the arsenal to combat SARS-CoV-2, including antivirals, which can be administered if a rapid diagnosis is made in order to distinguish SARS-CoV-2 as the pathogen causing infection.⁸

RSV is estimated to affect 64 million people worldwide and leads to 160,000 deaths each year.⁹ While most patients will recover at home after a week or two, this virus can lead to serious health problems, including more severe infections such as bronchiolitis or pneumonia. Recently, there have been innovations in RSV prevention specifically for certain populations, like children under 5, but infections are still possible.¹⁰

Most recently, the so-called “tripledemic” – flu, COVID-19, and RSV – caused a major burden on healthcare systems in the U.S. as three respiratory illnesses were circulating among the population at the same time.¹¹ This tripledemic led to 693,000 hospitalizations in the U.S. While these three are the most notable among viral infections, other viruses that can cause similar respiratory symptoms include rhinovirus, parainfluenza, and adenovirus, among others.¹²

Beyond viral infections, bacteria can also lead to respiratory illness. Some of these bacteria include Bordetella pertussis, Chlamydia pneumoniae, and Mycoplasma pneumoniae.¹³ In cases where a bacterial pathogen is present, an antibiotic may be needed and can be appropriately prescribed upon receipt of the result.

As we can see each respiratory pathogen is unique and as a result, the type of therapy that should be selected or not selected is also unique. This was evident during the COVID-19 pandemic where a diagnosis of COVID-19 would warrant a different therapeutic strategy from other respiratory illnesses, such as bacterial infections or influenza.¹⁴ Therefore, it is necessary that lab leaders implement a diagnostic strategy that employs syndromic testing to offer clinicians rapid and comprehensive results.

Syndromic testing enables lab professionals to run one compiled multiplexed test, rather than multiple individual tests necessitating only one sample from patients and reducing repeat testing for the laboratory and freeing up lab staff’s already reduced capacity.^15,16 Additionally, compared to a small plex PCR test, taking a multiplex approach using a rapid respiratory panel can reduce antibiotic use, length of inpatient stay, and isolation time.¹⁷

Syndromic tests should offer lab leaders rapid and accurate results, with features such as:^15,17-19

• Coverage for a wide range of pathogens, including viruses and bacteria, and co-infection detection
  

• Cost-effectiveness

• Scalability

• Ease of use and minimal staff training

• Rapid results

• Small sample volume

• Minimal hands-on time

• Centralized and available at point of care

• Small design

Studies have shown major antibiotic overuse occurs in children and adults when an upper respiratory tract infection is caused by a virus, inappropriately prescribing antibiotics occurs in up to 37% of children and 83% of adults. Rapid syndromic testing may help to contribute to antibiotic stewardship by reducing the number of antibiotics prescribed for viral upper respiratory tract infections, a critical aspect in combating antimicrobial resistance (AMR).²⁰ In 2019 alone, bacterial AMR led to approximately 1.27 million deaths worldwide and contributed to an additional 4.95 million deaths, driven by the misuse and overuse of antimicrobials.²¹ Leveraging syndromic testing could help promote antibiotic stewardship such that the right patients receive the right antibiotic.