02 Nov 2021
Tear antibodies to SARS-CoV-2: implications for transmission
Funding: This work was supported by the Victorian Government, the Medical Research Future Fund (MRFF) and Emergent Ventures Fast Grant along with NHMRC Fellowships.
SARS-CoV-2 is a contagious airborne pathogen that readily infects through the mucosa. COVID vaccinations in the arm effectively induce protective antibodies in the blood which target the virus’ spike and protect against severe disease. However, it is unclear if COVID vaccinations in the arm also induce similar protective antibodies locally at the mucosa.
In a study published today in Clinical & Translational Immunology, researchers from the Peter Doherty Institute for Infection and Immunity (Doherty Institute) looked at the SARS-CoV-2 antibodies present in blood, saliva and tears before and after Comirnaty (Pfizer-BioNtech) vaccinations.
The team, that included Kevin Selva, Samantha Davis, Ebene Haycroft, Wen Shi Lee, Ester Lopez, Helen Kent, Jennifer Juno, Amy Chung and Professor Stephen Kent from the Doherty Institute and Arnold Reynaldi and Professor Miles Davenport from the Kirby Institute, found high levels of spike-specific IgG antibodies – the major antibody type found in blood – in not only blood, but also saliva and tears post-vaccination.
On the other hand, the team did not observe an increase in spike-specific IgA antibodies – the major antibody type in mucosal secretions – in either saliva or tears post-vaccination. Furthermore, while Comirnaty vaccination induced high neutralizing antibodies in blood, limited neutralizing antibodies were detected in saliva or tears post-vaccination.
Together, our findings suggest that current COVID vaccinations in the arm might not be efficient in inducing neutralizing antibodies locally at the mucosa. Other vaccination strategies should be considered in addition to ongoing mitigation strategies to better protect high-risk front-line workers from breakthrough infections.