Researchers from Canada and the United States collaborated on a study on the vaccine. According to the results, the vaccine developed by Moderna and Pfizer-BioNTech forms antibodies in the salivary gland. They are found to be independent of the immune system.
The group found that just one dose of Pfizer-BioNTech’s BNT162b2 vaccine or Moderna’s mRNA-1273 product prompted salivary immunoglobulin A (IgA) antibodies towards the COVID-19 causative agent of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
Research Says Vaccines Generate Antibodies In Saliva
Interestingly, these antibodies were related to the secretory component within the exocrine gland instead of being derived from blood and entering via the gingival crevicular fluid.
University of Toronto’s Jen Gommerman and his colleagues suggest that these secretory IgA antibodies within the saliva may contribute to reducing the person-to-person transmission of SARS-CoV-2. A pre-print version of the research paper is out there on the medRx server while the article undergoes review by peers. “`
The beginning stage of the SARS-CoV-2 infection development starts when the receptor-binding domain (RBD) of the viral spike protein interacts with the host cell receptor angiotensin-converting enzyme 2 (ACE2) on the surface of epithelial cells within the upper tract of respiration.
The oral and nasal mucosa’s immune response creates the first defence. Saliva informs about the responses of antibodies at the mucosal sites to SARS-CoV-2. Antibodies derived from blood can penetrate saliva through the gingival crevicular fluid. Additionally, responses from local antibodies and secretory IgA can be formed in salivary glands.
Research has proved that the saliva of people exposed to SARS-CoV-2 contains infectious viral particles whose salivary viral load is positively correlated with COVID-19 symptoms, thereby highlighting the importance of saliva as a proxy for studying the primary mucosal immune response.
It was found via researchers that in the saliva of Covid-19 convalescent and acute patients, the IgA and IgG antibodies that work against the Covid spike protein and its RBD are readily found.
But, very little is thought concerning whether the current COVID-19 vaccines, which are all administered through the parenteral intramuscular (i.M.) route, can result in saliva immunity.
The team used an enzyme-related immunosorbent assay- (ELISA) method to investigate antibodies in saliva against the SARS-CoV-2 spike protein and the RBD amongst one hundred fifty lengthy-term care domestic residents (LTCH) who obtained i.M. shots of either the Moderna’s mRNA-1273 product or Pfizer BioNTech BNT162b2 vaccine.
Those who had no COVID-19 history 93% and 20% were certain for anti-RBD IgG and IgA and 94% and 41% were positive for anti-spike IgG and IgA.
Sparing of vaccines has led to a delay in the 2nd dose in countries like Canada and the United Kingdom. The experts examined whether antibodies in the saliva could be reported after a single vaccine shot and how long these antibody titers continued.
The group tested anti-SARS-CoV-2 antibodies of saliva over time in samples from a hundred and one healthy adults who received one shot of BNT162b2 and a second shot after approximately three months.
The results revealed that two weeks following the first shot, 97% and 93% of people were found certainly positive for anti-spike IgG and IgA, and among them, 52% and 41% respectively were found positive for anti-RBD IgG and IgA antibodies.
After three months of the first dose, diminished levels of salivary anti-spike and anti-RBD IgG were found. After two weeks of the second dose, recovering levels of the median IgG were reported.
The researchers hypothesized that the spike and RBD-particular IgA response triggered with the aid of BNT162b2 vaccination precipitated a localized IgA reaction within the oral cavity.
The researchers factor out that only one shot of BNT162b2 has been proven to blunt the SARS-CoV-2 transmission.