Initial LUMC studies on COVID-19 skin vaccine show promising results

15 June 2021• PRESSRELEASE

Preliminary research concerning the safety and efficacy of administering the Moderna COVID-19 vaccine into the skin instead of the muscle has been completed at the Leiden University Medical Center (LUMC). Results show dosages used were safe and that all participants produced antibodies. Antibody levels were comparable to those who’ve experienced COVID-19. Advantages of skin vaccinations are the smaller dose of vaccine required.

Skin vaccination is not a new technique, but it was previously unknown whether the method was effective for COVID-19 vaccines. An advantage of skin vaccination is that a smaller dosage is required – a fifth of the dose used for intramuscular vaccination – to offer the same level of protection. According to Geert Roozen, physician-researcher in Infectious Diseases: “During the first stage of our study, we saw that administration of one-tenth of the vaccine dose via the skin is safe and that all participants produced antibodies, comparable to that of a person who’s experienced COVID-19”.  

Promising results

The second stage of the study is on-going and almost complete. Researchers have now determined that one-fifth of the vaccine dose is safe to administer via the skin. “Since all participants from the first stage of the study produced significant amounts of antibodies, we expect that vaccinations consisting of one-fifth of the dosage are highly effective. We’re very hopeful, but we will wait to claim victory until we have all the antibody data available”, says Anna Roukens, an internist-infectiologist and head of the research. Furthermore, Rouken’s research will have to be reviewed by experts before it can be officially published.  

Vaccine shortage

Researchers at the LUMC are currently recruiting participants for the third stage of the study. “Similar to the second stage, we are now focusing on whether a fifth of the normal dosage generates as many antibodies as the intramuscular vaccine dose, but in a larger population. However, since the vaccination campaign in the Netherlands is going so well, a challenge has been finding people who haven’t been vaccinated yet”, Roozen notes. 

Even so, the researchers are not worried that the successful campaign in the Netherlands might render skin vaccination redundant. Roukens highlights: “There still is a vaccine shortage in large parts of the world. If we succeed, five times more people can be vaccinated with the same amount of vaccine and that’s what we’re doing it for.”

The collaborative study, together with the Centre for Human Drug Research (CHDR), is expected to be completed after the summer. As speed is an important element of COVID-19 related research, the scientists will soon be sharing their initial insights via MedRxiv. Those interested in participating in the third stage of the study can apply through


Researchers are still seeking funding through the crowdfunding campaign Wake Up To Corona for completion of the third stage of the study.  

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