Oral Vaccine for COVID Under Development in Japan

Researchers in Japan have been working on a new vaccine for COVID-19 that would be administered orally rather than by injection. The vaccine, under development by EPS Holdings, Inc. of Tokyo, is in the form of a pill that is placed under the tongue and contains part of the spike protein along with an adjuvant and is released in mucus rather than the blood.^{1 2}

EPS reported positive results of its early-stage trial for the vaccine in the journal Biology Methods & Protocols. The trial included nine monkeys divided into three groups; one group received 400 micrograms of the adjuvant; one group received 30 micrograms of the vaccine together with 400 micrograms of the adjuvant; and the last group got 150 micrograms of the vaccine with 400 micrograms of the adjuvant. The vaccines were administered sublingually (under the tongue)  three times at four-week intervals.³

One monkey in the lower vaccine dose group and two monkeys in the higher vaccine dose group showed positive results with blood specific antibodies present in blood plasma samples. Researchers theorized that this gave evidence for activation both a local immune response in the nose and mouth and a general immune response in the blood.⁴

The researchers hypothesized that an oral form of a COVID vaccine would allow for ease of administration, greater widespread access to the treatment, and be more effective at treating SARS-CoV-2 infections. Targeting the mucus rather than the blood has been shown to be more effective in inducing Immunoglobin A antibodies in mucus, which may be helpful in attacking viruses like coronaviruses that infect bronchial cells. The researchers point out that an oral delivery route may be more favorable than a nasal vaccine because nasal vaccines have been shown to cause adverse reactions.^{5 6}

According to a news release announcing the study:

The best way to neutralize viruses is before they can enter inside human cells but are only on the external surface of [skin] cells that line and produce mucus in the lungs, nose, and mouth.⁷

The researchers claim that there were no noticeable side effects in the monkeys and future studies with primates is planned.⁸

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