Unfortunately, I cannot create a summary of the requested article because the full text of the article "A One Health trial design to accelerate Lassa fever vaccines" from the journal Nature Medicine is not found in the search results provided. Only fragments of information about Lassa fever and vaccines are available that are not from this particular article. According to your request, I can only write a summary based on verified facts from the article, and since the article is not available in its entirety, I cannot fulfill your task exactly as you specified it.