Pfizer-BioNTech or Moderna Vaccines Induce Antibodies in Saliva

Aug, 2021 - By SMI

A team of researchers from the University of Toronto revealed that Pfizer-BioNTech and Moderna vaccines generate antibody responses against COVID-19 in the salivary gland.

The team of researchers used enzyme-linked immunosorbent assay- (ELISA) based method to study antibody responses in the salivary gland against coronavirus spike protein or S protein. The researchers analyzed these salivary antibodies in 150 long term care home residents who received two doses of either the Pfizer-BioNTech vaccine or Moderna vaccine. They revealed that the saliva of individuals who are exposed to coronavirus contain viral particles that are infectious and viral load in saliva is associated with COVID-19 symptoms. Thus, researchers stress on the fact that saliva can be considered as a proxy for understanding and analyzing the initial mucosal immune response. However, in some countries such as Canada and the U.K. vaccine dose sparing has caused delay in delivering second vaccine dose. Thus, the researchers, in this case, tested if salivary antibodies could be found in individuals who received a single dose. They also analyzed how long these antibody titers lasted. They revealed that a single dose induced salivary immunoglobulin A (IgA) antibodies against COVID-19. More importantly, IgA were related to the secretory component in the salivary gland. The researchers revealed that secretory component-associated anti-spike and anti-receptor binding domain (RBD) antibodies could be detected in 30% and 58% of participants, respectively. The researchers found 94% and 41% were positive for anti-spike immunoglobulin G and IgA, respectively, and 93% and 20% were positive for anti-RBD IgG and IgA in participants with no previous history of SARS-CoV-2 infection.

The researchers concluded that after three months of the first dose, they observed decline in the median levels of salivary anti-spike and anti-RBD IgG. However, they found that two weeks following second dose, the median levels of either salivary anti-spike were elevated or anti-RBD IgG were recovered. They suspected that vaccination cause localized IgA response in the oral cavity.