TY - JOUR

T1 - Short-Lived Antibody-Mediated Saliva Immunity against SARS-CoV-2 after Vaccination

AU - Madsen, Johannes Roth

AU - Holm, Bettina Eide

AU - Pérez-Alós, Laura

AU - Bayarri-Olmos, Rafael

AU - Rosbjerg, Anne

AU - Fogh, Kamille

AU - Pries-Heje, Mia Marie

AU - Møller, Dina Leth

AU - Hansen, Cecilie Bo

AU - Heftdal, Line Dam

AU - Hasselbalch, Rasmus Bo

AU - Hamm, Sebastian Rask

AU - Frikke-Schmidt, Ruth

AU - Hilsted, Linda

AU - Nielsen, Susanne Dam

AU - Iversen, Kasper Karmark

AU - Bundgaard, Henning

AU - Garred, Peter

N1 - Publisher Copyright: © 2023 American Society for Microbiology. All rights reserved.

PY - 2023

Y1 - 2023

N2 - Knowledge about the effect of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on immunity reflected in the saliva is sparse. We examined the antibody response in saliva compared to that in serum 2 and 6 months after the first vaccination with the BNT162b2 vaccine. Four hundred fifty-nine health care professionals were included in a prospective observational study measuring antibody levels in saliva and corresponding serum samples at 2 and 6 months after BNT162b2 vaccination. Vaccinated, previously SARS-CoV-2-infected individuals (hybrid immunity) had higher IgG levels in saliva at 2 months than vaccinated, infection-naive individuals (P , 0.001). After 6 months, saliva IgG levels declined in both groups (P , 0.001), with no difference between groups (P = 0.37). Furthermore, serum IgG levels declined from 2 to 6 months in both groups (P , 0.001). IgG antibodies in saliva and serum correlated in individuals with hybrid immunity at 2 and 6 months (r = 0.58, P = 0.001, and r = 0.53, P = 0.052, respectively). In vaccinated, infection-naive individuals, a correlation was observed at 2 months (r = 0.42, P , 0.001) but not after 6 months (r = 0.14, P = 0.055). IgA and IgM antibodies were hardly detectable in saliva at any time point, regardless of previous infection. In serum, IgA was detected at 2 months in previously infected individuals. BNT162b2 vaccination induced a detectable IgG anti-SARS-CoV-2 RBD response in saliva at both 2 and 6 months after vaccination, being more prominent in previously infected than infection-naive individuals. However, a significant decrease in salivary IgG was observed after 6 months, suggesting a rapid decline in antibody-mediated saliva immunity against SARS-CoV-2, after both infection and systemic vaccination. IMPORTANCE Knowledge about the persistence of salivary immunity after SARS-CoV-2 vaccination is limited, and information on this topic could prove important for vaccine strategy and development. We hypothesized that salivary immunity would wane rapidly after vaccination. We measured anti-SARS-CoV-2 IgG, IgA, and IgM concentrations in saliva and serum in both previously infected and infection-naive individuals, 2 and 6 months after first vaccination with BNT162b2, in 459 hospital employees from Copenhagen University Hospital. We observed that IgG was the primary salivary antibody 2 months after vaccination in both previously infected and infection-naive individuals, but dropped significantly after 6 months. Neither IgA nor IgM was detectable in saliva at either time point. Findings indicate that salivary immunity against SARS-CoV-2 rapidly declines following vaccination in both previously infected and infection-naïve individuals. We believe this study shines a light on the workings of salivary immunity after SARS-CoV-2 infection, which could prove relevant for vaccine development.

AB - Knowledge about the effect of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on immunity reflected in the saliva is sparse. We examined the antibody response in saliva compared to that in serum 2 and 6 months after the first vaccination with the BNT162b2 vaccine. Four hundred fifty-nine health care professionals were included in a prospective observational study measuring antibody levels in saliva and corresponding serum samples at 2 and 6 months after BNT162b2 vaccination. Vaccinated, previously SARS-CoV-2-infected individuals (hybrid immunity) had higher IgG levels in saliva at 2 months than vaccinated, infection-naive individuals (P , 0.001). After 6 months, saliva IgG levels declined in both groups (P , 0.001), with no difference between groups (P = 0.37). Furthermore, serum IgG levels declined from 2 to 6 months in both groups (P , 0.001). IgG antibodies in saliva and serum correlated in individuals with hybrid immunity at 2 and 6 months (r = 0.58, P = 0.001, and r = 0.53, P = 0.052, respectively). In vaccinated, infection-naive individuals, a correlation was observed at 2 months (r = 0.42, P , 0.001) but not after 6 months (r = 0.14, P = 0.055). IgA and IgM antibodies were hardly detectable in saliva at any time point, regardless of previous infection. In serum, IgA was detected at 2 months in previously infected individuals. BNT162b2 vaccination induced a detectable IgG anti-SARS-CoV-2 RBD response in saliva at both 2 and 6 months after vaccination, being more prominent in previously infected than infection-naive individuals. However, a significant decrease in salivary IgG was observed after 6 months, suggesting a rapid decline in antibody-mediated saliva immunity against SARS-CoV-2, after both infection and systemic vaccination. IMPORTANCE Knowledge about the persistence of salivary immunity after SARS-CoV-2 vaccination is limited, and information on this topic could prove important for vaccine strategy and development. We hypothesized that salivary immunity would wane rapidly after vaccination. We measured anti-SARS-CoV-2 IgG, IgA, and IgM concentrations in saliva and serum in both previously infected and infection-naive individuals, 2 and 6 months after first vaccination with BNT162b2, in 459 hospital employees from Copenhagen University Hospital. We observed that IgG was the primary salivary antibody 2 months after vaccination in both previously infected and infection-naive individuals, but dropped significantly after 6 months. Neither IgA nor IgM was detectable in saliva at either time point. Findings indicate that salivary immunity against SARS-CoV-2 rapidly declines following vaccination in both previously infected and infection-naïve individuals. We believe this study shines a light on the workings of salivary immunity after SARS-CoV-2 infection, which could prove relevant for vaccine development.

KW - IgA

KW - IgG

KW - IgM

KW - immunity

KW - saliva

KW - SARS-CoV-2 vaccination

U2 - 10.1128/spectrum.04947-22

DO - 10.1128/spectrum.04947-22

M3 - Journal article

C2 - 36877077

AN - SCOPUS:85154026590

VL - 11

JO - Microbiology spectrum

JF - Microbiology spectrum

SN - 2165-0497

IS - 2

M1 - e04947-22

ER -