Researchers studying SARS-CoV-2 — the virus that causes COVID-19 — have identified new methods that should allow future vaccines to be administered orally.
The approach could make the preventative medicines easier to administer and potentially more effective against the virus, the team from Japan claim.
The most effective time to disable viruses is before they have entered the body’s cells proper, when they are just on the outside of the so-called epithelial cells that line the lung, nose and mouth and produce protective mucus.
Mucus contains a class of antibodies called Immunoglobulin A that are capable of disabling viruses, but the immune system must be first primed for a given virus.
In their study, the team demonstrated a new vaccine that can induce the production of Immunoglobulin A against SARS-CoV-2 in monkeys when given “sublingually” — that is, under the tongue.
The study was undertaken by Dr Shin Nakamura of Primate Agora — a Kaizu, Japan-based non-profit organization — and his colleagues.
The researchers wrote: “The sublingual vaccine stimulated mucosal immune response to produce antigen-specific secretory Immunoglobulin A antibodies in [phlegm] and/or saliva.”
The vaccine, they added, “also affected systemic immune response to produce Immunoglobulin A in [blood] plasma.
“The SARS-CoV-2 sublingual vaccine […] showed reasonable efficacy in a non-human primate model.”
This is not the first time that researchers have experimented with vaccines delivered by alternative routes, such as orally or nasally.
These approaches tend to be more effective in inducing Immunoglobulin A production than those vaccines delivered conventionally, via injections under the skin.
However, previous studies with nasal vaccines have resulted in unpleasant side effects.
In contrast, the new study — while only tested pre-clinically on monkeys so far — appears to work effectively with no discernable side effects.
The full findings of the study were published in the journal Biology Methods and Protocols.
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