First Documented Coronavirus Reinfection Raises Many Questions With Few Answers.
BLITZER: With the U.S. death toll from the coronavirus now passing 177,000. Researchers in China say a 33-year-old man living in Hong Kong is the first person confirmed to have been reinfected with the coronavirus. Representative of the World Health Organization, however, cautioned not to jump to conclusions about the findings, at least not yet. CNN's Brian Todd is joining us. He's got new information, he's got details. What are you learning, Brian?</s>BRIAN TODD, CNN CORRESPONDENT: Right, Wolf. This is a potentially serious setback tonight in our war against coronavirus. This new case you mentioned out of Hong Kong really does put into question that belief that so many of us have had that if you got coronavirus once, you couldn't get it again.</s>TODD (voice-over): Tonight, researchers at the University of Hong Kong say a 33-year-old man living in that city who they studied, contracted coronavirus two separate times this year, about four and a half months apart.</s>UNIDENTIFIED FEMALE: This does seem to be initial evidence that at least some people could be infected more than once with coronavirus. We just don't know, at this point, how common it is, but it does seem to be possible that it can happen.</s>TODD (voice-over): The Hong Kong researchers call this the first ever documented case of reinfection of COVID-19. But experts around the world say more research is needed before drawing that conclusion.</s>DR. MARIA VAN KERKHOVE, TECHNICAL LEAD COVID-19: We need to not jump to any conclusions to say if -- even if this is the first documented case of reinfection. It is possible, of course.</s>TODD (voice-over): As for why that may be possible, two studies last month out of Britain and Spain said that after people are infected with COVID-19, their natural immunity could diminish within months, meaning antibodies, your immune systems memory of the virus that could help fight it off again, could decrease after a month or two.</s>UNIDENTIFIED MALE: Your body forgets they ever were infected. And they come back and get you again every year. You can be reinfected by the same cold virus every year and get the same cold.</s>TODD (voice-over): Doctors and patients in the United States have reported cases of recovered patients getting coronavirus again. But COVID testing has a lot of false positives, so in many cases, they haven't been able to actually prove reinfection. Dr. Clay Ackerly (ph), an internist in Washington, D.C. believes he had a patient who contracted the virus twice, though he says he can't prove it. Dr. Ackerly says his patient had the virus, cleared it, he says, then tested negative twice.</s>DR. CLAY ACKERLY, INTERNIST, WASHINGTON, D.C.: And in mid-June, had a family member who caught coronavirus again, came into the home and caught it second time from that family member.</s>TODD (voice-over): Bolstering the Hong Kong researchers claim according to experts, they tested not just for the fingerprints of the virus, the traces left over after an infection. But the Hong Kong researchers compared the genetic sequences of the virus from the man's first infection and his second infection and found significant genetic differences. So they believe he was infected two separate times. If we can get coronavirus twice, what does it mean for a potential vaccine?</s>UNIDENTIFIED FEMALE: We don't yet know what this is going to mean for vaccination. If this will mean we need to be repeatedly vaccinated for coronavirus, but it will certainly have implications for how we design a vaccine and how we study that vaccine.</s>TODD: Experts say if this case out of Hong Kong proves we can get reinfected, it's going to make it tougher for us to reach that critical mass of people who have immunity, so called herd immunity. Specifically, they say it's going to be tougher for us to get herd immunity through natural infections. So it will be important for us to get herd immunity through a vaccine and that means that the vaccines that are in development now have to be designed to help us do that. Wolf?</s>BLITZER: All right, Brian, thanks for that report. Brian Todd reporting. Coming up, President Trump attacking his own health officials as he pushes the speed up potential coronavirus, vaccines and treatments just ahead of the first night of the Republican Convention.