Oral Fluids as an Alternative to Serum for Detecting Antibody Response After COVID-19 Vaccination?

​Dr Chaminda Jayampath Seneviratne (Dr Jaya) and Dr Preethi Prajod from the Singapore Oral Multiomics Initiative (SOMI) team led a study on whether oral fluids such as Gingival Crevicular Fluid (GCF) could be used as a less invasive alternative to serum, to detect antibody responses after COVID-19 vaccination. 

Dr Jaya’s research team, in collaboration with Singapore General Hospital (SGH), had previously won the SingHealth Publish! Award for identifying that commercial mouth rinses may have a long-lasting effect on reducing SARS-CoV-2 levels in the saliva of COVID-19 patients. When aerosol generation is inevitable, such as in a clinical dental setting, these mouth rinses may serve as a useful pre-procedural transmission mitigation technique. Following this successful collaboration, Dr Jaya’s team partnered with SGH again to further investigate various oral fluids that could be used as a non-invasive alternative to venepuncture for serum samples to monitor vaccine-induced immunity comfortably and effectively. The global vaccination campaign against Coronavirus Disease 2019 (COVID-19) is underway to limit the pandemic. While these vaccinations have been shown to prevent severe disease, the level of immunity required to prevent respiratory mucosal infection is not yet fully understood. As secreted antibodies may serve as surrogates for mucosal immunity, it is desirable to establish a non-invasive screening approach, such as oral fluids, to track them over time. Therefore, Dr. Jaya’s research team compared immune responses in the blood of healthy professionals from the healthcare sector to those with GCF and saliva following two intramuscular doses of the Pfizer/BioNTech-BNT162b2 vaccine.

Within limitations, the research team observed that GCF could be a less invasive alternative to serum and more appropriate than saliva to detect antibody responses by current COVID-19 vaccines, if the GCF collection procedure could be standardised. Investigating GCF as a potential diagnostic fluid for vaccineinduced immunity stands to reason as a non-invasive alternative to venepuncture for serum samples.