There is no such research saying that, there have been some reports of reinfection, but in the case in Japan the indication is that the testing was flawed. What is observed and best guess by scientists are similarity to how antibodies developed and responded to the original SARS-CoV. Only recently have an antibody test for SARS-CoV2 been developed, which should help research. https://doi.org/10.1002/jmv.25727
From other coronaviruses including the first SARS there is a long lasting t-cell mediated immunity response. It is reported to be still active in tested humans and animals, so high expectation of lifetime response, compared to more limited lifetime of the antobodies. But how it works it may not stop an reinfection but should very likely cause a much more muted illness.
Well a Dr. heading pneumonic research observing the course of the virus in several patients can, at a minimum, be called....research.
Quick article link touching on the immunity factor of recovery and relapse or bad diagnosis.
75,000 ill, 2,000 deaths, many thousands recovered: Can you get coronavirus twice?
With no end to the coronavirus outbreak in sight, health officials grapple with the issue of whether recovered patients can get reinfected.
www.usatoday.com