Non-Invasive Detection of Viral Antibodies Using Oral Flocked Swabs

Salivary antibodies are useful in surveillance and vaccination studies. However, low antibody levels and degradation by endonucleases are problematic. Oral flocked swabs are a potential non-invasive alternative to blood for detecting viral antibodies. Serum and saliva collected from 50 healthy volunteers were stored at −80°C; dried swabs at room temperature. Seroprevalence for Cytomegalovirus (CMV), Varicella-Zoster virus (VZV), Epstein-Barr virus (EBV), Measles and Mumps IgG antibodies were determined using commercial ELISAs and processed on an automated platform. For each antibody, swabs correlated well with saliva. For CMV IgG, VZV IgG, and EBV EBNA-1 IgG and VCA IgG, the swab sensitivities compared to serum were 95.8%, 96%, 92.1% and 95.5% respectively. For Measles IgG, swab sensitivity was 84.5%. Mumps IgG displayed poor sensitivity for oral swabs (60.5%) and saliva (68.2%). Specificities for IgG antibodies were 100% for CMV, EBV and Mumps. Specificities for VZV and Measles could not be determined due to seropositive volunteers. As oral flocked swabs correlate well with serum, are easy to self-collect and stable at room temperature further research is warranted. Highlights Oral flocked swabs are an easy, self-collection method for measuring viral antibodies. Viral IgG is stable on dried oral flocked swabs for at least two years. Oral swabs are highly sensitive for CMV, VZV, and EBV IgG. Oral swabs are potentially useful for surveillance and clinical microbiology.