In a new study, researchers found that vaccines delivered via skin may offer better protection against respiratory diseases.
They found that such vaccines may help generate lung T cells and provide protection against infectious diseases, with implications for the prevention of COVID-19.
The research was conducted by a team at Brigham and Women’s Hospital.
Among infectious diseases that have caused pandemics and epidemics, smallpox stands out as a success story.
Smallpox vaccination led to the disease’s eradication in the twentieth century.
Until very recently, the smallpox vaccine was delivered using a technique known as skin scarification (s.s.), in which the skin is repeatedly scratched with a needle before a solution of the vaccine is applied.
Almost all other vaccines today are delivered via intramuscular injection, with a needle going directly into the muscle, or through subcutaneous injection to the layer of tissue beneath the skin.
Historically, smallpox vaccines used the live vaccinia virus (VACV).
More recently, the Food and Drug Administration has approved the use of modified vaccinia Ankara (MVA), a modern alternative that lacks about 10 percent of the parent genome and cannot replicate in human cells, thus avoiding the serious side effects seen with VACV.
MVA, as a smallpox vaccine, is injected subcutaneously.
In the study, the team set out to determine if the skin scarification route of immunization with MVA could provoke a more effective T cell response than other routes of immunization.
The team inoculated mice using either skin scarification, intramuscular, subcutaneous, or intradermal injection.
Skin scarification generated more T cells, produced greater numbers of lung-specific T cells, and provided superior protection against lethal viral doses than the others.
The work has motivated the team to explore the potential for using the MVA vector and skin scarification technique to develop more powerful — and, potentially universal — vaccines against other infectious illnesses such as influenza and coronaviruses.
One author of the study is Thomas Kupper, MD, the chair of the Department of Dermatology.
The study is published in Npj vaccines.
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