President Trump is symptom-free, has required no supplemental oxygen and says he is feeling “great,” according to a statement released on Wednesday by the White House physician, Dr. Sean P. Conley.
But he offered no further details about Mr. Trump’s treatment, including whether he was still taking a steroid treatment to treat the disease.
In addition, Dr. Conley’s statement that a test on Monday revealed that Mr. Trump had antibodies to the coronavirus was immediately questioned by immunologists, who said the results were virtually meaningless given that only days earlier, the president had received a large dose of an experimental antibody cocktail that would show up in his bloodstream.
“It doesn’t give us a lot of information, and it doesn’t make much sense,” said Deepta Bhattacharya, an immunologist at the University of Arizona.
In the letter, Dr. Conley noted that an antibody test conducted on Mr. Trump “late Thursday night” showed no detectable antibody levels. A subsequent test, drawn on Monday, the day Mr. Trump left Walter Reed National Military Medical Center, did show detectable levels of immunoglobulin G, the antibody created by the body’s immune system to fight the virus.
On Friday, Mr. Trump received an infusion of a treatment that is still being tested in clinical trials. The cocktail, made by Regeneron, is thought to help the body mount an immune response by providing an infusion of powerful antibodies.
Hala Mirza, a spokeswoman for Regeneron, said most of the standard tests for so-called IgG antibodies would not distinguish between ones that the body produced on its own and the ones that were made by Regeneron. “Given the volume of IgG antibodies delivered in our therapy, and the timing of these tests, it is likely that the second test is detecting” the Regeneron antibodies, she said.
Ms. Mirza said that early data released late last month showed “the patients most likely to benefit from this treatment have a similar profile to President Trump,” in that they had undetectable antibodies and were early in the course of their disease.
Dr. Bhattacharya said the results that Dr. Conley shared wouldn’t shed much light on Mr. Trump’s condition. “The way that it’s implied is that he’s made a normal immune response, but I don’t see how you would be able to tell the difference,” he said.
As a result, it was not immediately clear what the results of a test taken two days earlier meant in terms of Mr. Trump’s initial diagnosis, the course of his illness or his fitness to resume a regular work or campaign schedule.
Even if Mr. Trump had developed his own antibodies, Angela Rasmussen, a virologist from Columbia University, said, the results are “consistent with what we would expect for immune responses,” and the appearance antibodies “is within the normal time frame that you’d expect to see IgG start to go up.” These antibodies, she said, are more likely than other types to neutralize the virus.
“This is almost a guaranteed way of putting out good news,” Dr. Rasmussen said.
Questions have persisted about the timing of Mr. Trump’s infection and whether he was contagious during his debate with Joseph R. Biden Jr. last week. Dr. Conley has declined to say when Mr. Trump last tested negative for the coronavirus, and the White House has acknowledged that the president was not tested every day.
Marion Pepper, an immunologist at the University of Washington, said the fact that Mr. Trump had no detectable antibodies on Thursday does not shed much new light on when he was infected. She pointed to a study from April that found most people develop antibodies eight to 14 days after infection. She said the earliest that antibodies have been detected is about five days, “so it narrows it down, but doesn’t define the infection day.”
The brief note marked the second consecutive day that Mr. Trump’s medical team did not hold a question-and-answer session with reporters. The note from Dr. Conley did not provide other medical updates, such as whether he is continuing to take the steroid dexamethasone, and whether he has completed his course of remdesivir, an experimental antiviral treatment.
Doctors have said that Mr. Trump’s medical team has provided an incomplete picture of his health since his infection, declining to provide the results of chest X-rays or lung scans that could give a better sense of how sick he is.
For days, Mr. Trump has said he was “feeling great,” but several experts in Covid-19 said that he is entering a pivotal phase in the disease where some patients take a turn for the worse. Dr. Conley said Monday that Mr. Trump was not “out of the woods” and that his team would breathe a sigh of relief if he continued to do well through next Monday.