I am a third year student, and I have had several research internship experiences. Typically, summer internships can last between 8-10 weeks, but many are currently being disrupted due to COVID-19. I had an internship at Mayo clinic that was cancelled due to the disease, and many of my friends have had their internships shortened to remote internships that are 4 weeks or less. Do not let this deter you from applying, though! Considering the current healthcare crisis, workers in public health and policy and needed now more than ever! I hope this helps, and good luck searching!