Dr. Scott Gottlieb told CNBC on Monday he believes that most people who had the coronavirus will have "some level" of immunity.
"Now how long that immunity lasts, how strong it is, we don't know. It might not last that long in certain people. It might not be that strong, so you can get reinfected but perhaps not get as sick," he said on "Squawk Box."
Gottlieb, the former commissioner of the Food and Drug Administration, was responding to a warning put out last week by the World Health Organization, which later clarified its position.
The WHO on Friday advised governments against issuing so-called immunity passports to people who have antibodies for Covid-19 to travel or return to work "assuming that they are protected against re-infection."
"There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection," the organization wrote in a scientific brief dated April 24.
In follow-up tweets Saturday, the WHO clarified that it also expects Covid-19 antibodies will "provide some level of protection."
Gottlieb said he believes the latest WHO statement was "characteristically cautious and muddled."
"If this behaves like every other virus, and every other coronavirus, you're going to develop antibodies and they'll confer some level of immunity," said Gottlieb, a CNBC contributor who sits on the boards of Pfizer and biotech company Illumina.
"It's fair to say, if you have antibodies, you test yourself and you have antibodies, it's no guarantee you can't get it again. That's a reasonable statement. But you're going to have some level of immunity."
However, Gottlieb has previously warned about the level of accuracy of some antibody tests being used in the U.S., telling CNBC last week they could give "a very high false positive rate."