Scientists continue attempts to develop alternative types of COVID-19 ‘vaccines’ other than the typical injection in the arm.
Researchers from Japan’s Intelligence & Technology Lab Inc. and the Biomedical Institute of NPO Primate Agora are experimenting with an “under-the-tongue vaccine” (sublingual) in primates.
“Mucosal vaccine for sublingual route was prepared with recombinant SARS-CoV-2 spike protein receptor binding domain (RBD) antigen and poly(I:C) adjuvant components,” the abstract of a study published Wednesday by Oxford University Press states.
The researchers concluded that “it was indicated that this sublingual vaccine could elicit mucosal immune response to produce secretory IgA antibodies to SARS-CoV-2.”
“This study is yet to examine the exact safety and efficacy using genomic markers described in previous papers in mice. Further studies on these points are in progress using the preclinical non-human primate model,” they added.
Fierce Biotech shared additional details:
The researchers’ vaccine is a combination of an antibody against the receptor-binding domain of the spike protein on the SARS-CoV-2 virus and an adjuvant called poly(I:C), a synthetic double-stranded RNA that binds to genes associated with viral infection. It activates a subset of immune cells called antigen-presenting cells that initiate the adaptive immune response by displaying captured antigens to B and T cells, which then target the invader.
Despite being a “potent” adjuvant, the researchers wrote, poly(I:C) hasn’t been approved yet for use in vaccines but is used in oncology as a complement to immunotherapy. Some studies in mice have shown that the compound increases levels of proinflammatory cytokines when administered via the nose, which raises the risk of side effects like pain, fever and swelling.
Perhaps a different route of administration would temper the potential for adverse effects, the scientists reasoned.
The primates received three vaccinations to start, administered four weeks apart. A booster dose was given 15 weeks after the final round in the primary series. The scientists also included a control group of three primates.
After the booster dose, the team analyzed the amount and type of antibodies found in fluids from the monkeys’ mouths. They observed a desirable dose-dependent increase in IgA antibodies, “guardians of the oral and nasopharyngeal galaxy” that prevent the virus from attaching to cells in the mucosa. What’s more, they didn’t detect any obvious side effects nor did they see an increase in IgE antibodies, which are associated with an allergic response.
Sublingual vaccines are being touted as potentially more effective and easily administered than injections.
Sky News writes:
An under-the-tongue vaccine wouldn’t only be easier to administer, but may also be more effective at combatting COVID-19 than an injection, according a study published by Oxford University Press.
That’s because the best way to neutralise viruses is before they can enter human cells, while they are just on the external surface of cells in the lungs, nose, and mouth.
A specific class of antibodies known as Immunoglobulin A operate in mucus and can disable viruses – and experts say a vaccination that rapidly produces these antibodies would better prevent disease.
Anyone who opposes the experimental COVID-19 injections will deny under-the-tongue ‘vaccines.’
The mode of delivery doesn’t matter.
The spike protein is toxic for the body.
“It’s not yet clear how efficacious the vaccine is against COVID-19 nor how long protection might endure. The researchers are currently conducting additional studies to address these questions, looking at changes in markers of gene expression to better quantify how well it works,” Fierce Biotech noted.
The full abstract for the study, titled “SARS-CoV-2 sublingual vaccine with RBD antigen and poly(I:C) adjuvant: Preclinical study in cynomolgus macaques,” reads:
Mucosal vaccine for sublingual route was prepared with recombinant SARS-CoV-2 spike protein receptor binding domain (RBD) antigen and poly(I:C) adjuvant components. The efficacy of this sublingual vaccine was examined using Cynomolgus macaques. Nine of the macaque monkeys were divided into three groups of three animals: control [just 400 µg poly(I:C) per head], low dose [30 µg RBD and 400 µg poly(I:C) per head], and high dose [150 µg RBD and 400 µg poly(I:C) per head], respectively. N-acetylcysteine (NAC), a mild reducing agent losing mucin barrier, was used to enhance vaccine delivery to mucosal immune cells. RBD-specific IgA antibody secreted in pituita was detected in two of three monkeys of the high dose group and one of three animals of the low dose group. RBD-specific IgG and/or IgA antibodies in plasma were also detected in these monkeys. These indicated that the sublingual vaccine stimulated mucosal immune response to produce antigen-specific secretory IgA antibodies in pituita and/or saliva. This sublingual vaccine also affected systemic immune response to produce IgG (IgA) in plasma. Little RBD-specific IgE was detected in plasma, suggesting no allergic antigenicity of this sublingual vaccine. Thus, SARS-CoV-2 sublingual vaccine consisting of poly(I:C) adjuvant showed reasonable efficacy in a non-human primate model.
