Medical experts say there's no evidence right now that people are immune to COVID-19 if they've been infected.

President Donald Trump has said he is immune to COVID-19, but does not have any evidence.


"The word immunity means something," said President Trump.



Medical experts agree that it does mean something, and that's why public health specialist Dr. Saju Mathew is so cautious using that word.



"I would never use the word immunity with COVID-19," he says. 


"There's no sense that we're getting in the scientific field that you can actually be immune to COVID-19. We know that you can build some level of immunity for maybe a couple of months but we also have studies that have shown that after two months the immunity goes down."




There are also documented cases of people who had COVID-19 and then got re-infected.




The CDC has specifically cautioned people not to assume they are immune, saying immunity has "not yet been established."




It is something scientists are working on.

The U.S.National Cancer Institute just launched the Serological Sciences Network for COVID-19, or SeroNet.

O


n a webinar, Douglas Lowy, principal deputy director of the National Cancer Institute, said it will be working to answer a number of questions in what's been 


described as the nation's largest coordinated effort to study the immune response to COVID-19.




 "I am hopeful that, by the end of the year, that we will have at least partial answers," he says.