Amidst the changing world of medical testing, saliva is making a comeback as a key tool for identifying respiratory diseases. Once a well-known method in early scientific studies, its use had diminished over the years. However, the advantages of saliva, including its low cost, ease of collection, and independence from complex supply processes, are now being appreciated anew. This resurgence was especially evident during the COVID-19 pandemic, when saliva proved to be a practical and effective means for detecting the virus, leading to the approval of many saliva-based tests. As we look to the future, saliva, containing both respiratory and immune system components, is set to play a significant role in everything from daily medical tests to monitoring disease trends and immune responses after vaccination.
This shift is underscored by the collective research efforts of scientists from Yale School of Public Health, led by Dr. Anne Wyllie, and supported by her colleagues including Dr. Claire Laxton, Dr. Chikondi Peno, Dr. Anne Hahn, Dr. Orchid Allicock, and Dr. Stephanie Perniciaro, as detailed in their recent study published in The Lancet Microbe. Their work delves into the potential of saliva as a non-invasive, accessible, and sensitive sample type, opening new avenues in disease surveillance and patient care.
The team’s investigation reveals saliva’s comparable efficacy to traditional respiratory specimens in pathogen detection. In particular, saliva has shown promise in detecting a range of viruses like influenza and SARS-CoV-2, with some pathogens even exhibiting increased sensitivity in saliva samples. The simplicity and non-invasiveness of saliva collection make it an appealing alternative to more conventional methods, potentially enhancing patient compliance and broadening the scope of community-based testing.
“From the studies included, average concordances between saliva and swabs for the detection of RSV and influenza were consistently over 90% in adults,” remarked Dr. Claire Laxton, underscoring saliva’s robust clinical utility beyond just existing SARS-CoV-2 testing.
The researchers also explored the genomic surveillance capabilities of saliva. “Saliva samples offer an accessible and cost-effective medium for the genomic surveillance of respiratory pathogens,” noted Dr. Chikondi Peno, highlighting the importance of saliva in the contemporary landscape of medical diagnostics.
Further, the study illuminates the presence of a broad spectrum of immune biomarkers in saliva. These markers are indicative of recent or early-stage infections and play a critical role in enhancing disease surveillance. The presence of antibodies in saliva provides valuable insights into an individual’s immune response to infections and vaccinations.
The authors emphasize the need for standardized saliva collection and processing techniques to ensure high-quality data acquisition. They also advocate for the inclusion of saliva as a comparator sample type in surveillance studies, which could significantly expand its utility in diagnosing a range of pathogens.
In conclusion, the research team, led by Drs. Claire Laxton and Chikondi Peno, highlights the transformative potential of saliva in respiratory disease diagnostics and surveillance. “The benefits of saliva collection and its avenues for low-cost collection and testing make it well-suited for sustainable surveillance in low-resource settings,” concluded Dr. Laxton, emphasizing the practical applications of their findings.
JOURNAL REFERENCE
Laxton CS, Peno C, Hahn AM, Allicock OM, Perniciaro S, Wyllie AL. The potential of saliva as an accessible and sensitive sample type for the detection of respiratory pathogens and host immunity. Lancet Microbe. 2023 Oct;4(10):e837-e850. DOI: https://doi.org/10.1016/s2666-5247(23)00135-0.
ABOUT THE AUTHORS
Dr. Claire Laxton completed a Wellcome Trust doctorial training program in antimicrobials and antimicrobial resistance at the University of Nottingham, U.K in 2023. During this, she obtained a MRes, studying Gram negative cell membrane physiology, followed by a PhD, studying Pseudomonas aeruginosa virulence factors in chronic wound infections, under Prof Kim Hardie. In 2020, Claire interrupted her PhD to work in the UK national COVID testing labs, and having developed an interest in molecular diagnostics, she decided to pivot from uncovering therapeutic targets, to developing diagnostic assays. She is now a Postdoctoral Associate in the Wyllie Lab at Yale School of Public Health, working on developing saliva-based molecular assays and expanding the SalivaDirect platform to test for respiratory pathogens beyond SARS-CoV-2, as well as non-communicable diseases.
Dr Chikondi Peno is a Postdoctoral Associate in the Department of Epidemiology of Microbial Diseases at the Yale School of Public Health, Yale University. Her research integrates molecular microbiology, immunological data, and epidemiological data to understand the influence of microbial community ecology (microbiome) on pathogen transmission and disease outcomes. Her research at Yale investigates the drivers of Streptococcus pneumoniae transmission, epidemiology of respiratory viruses in children, and the role respiratory microbiota on respiratory health in infants. Beyond this, Dr Peno is also enthusiastic in implementing cheaper tests to detect respiratory pathogens to improve robust surveillance of respiratory pathogens in low- and middle-income countries. For this, she is leading a study aiming to implement a saliva-based cost-effective diagnostic test for major respiratory pathogens including SARS-CoV-2, RSV and Influenza A and B in Malawi, Africa. Dr Peno holds a PhD in Clinical Sciences and Community Health from University of Edinburgh and MSc in Infectious Diseases from London School of Tropical Medicine.
