Full transcript: Tulio de Oliveira on "Face the Nation," December 12, 2021

The following is a full transcript of an interview with Tulio de Oliveira, director of the Centre for Epidemic Response and Innovation in South Africa, that aired Sunday, December 12, 2021, on "Face the Nation."

MARGARET BRENNAN: We want to go now to Dr. Tulio de Oliveira. He leads a team of South African scientists that first reported Omicron to the World Health Organization. He joins us now from Stellenbosch, South Africa. Good morning.

TULIO DE OLIVEIRA: Good morning and good morning to your viewers.

MARGARET BRENNAN: You are seeing the impact of Omicron firsthand, who is getting sick, and is this mild or severe illness?

DE OLIVEIRA: OK, so- so basically the- the Omicron, it's only a few weeks old. We detected it very, very quick here. We estimate that the date of origin of these variants, it is either the end of October, or the beginning of November. So, what it means? It means that only now we begin to see the sick patients to arrive in the hospital. Why that? Is because normally take a few weeks between infection and the need for hospitalization. So, what we saw in the last few days, it is increasing admission. And that it is something that we are really looking very carefully at the data in South Africa.

MARGARET BRENNAN: Is it too early to say if the illness is mild?

DE OLIVEIRA: So- so it's- the responsible way to say, is that a little bit early to say that the- it's mild. Why that? There are two main reasons. The first is that normally waves of infections tend to increase with the younger population which will not develop a disease. And the second is that between vaccination and previous infection, that would be most of the population in South Africa. For example, we estimated between 60 to 80% of the population, but previously infected. And even with the vaccine coverage of 40%, it means that you have large pockets of population immunity. So- so that's what we're going to have to tease apart. If the mild case is due to young people getting infected or if the previous population immunity from infection and vaccination are responsible for- for decreasing the number of hospitalized individuals.

MARGARET BRENNAN: Is Omicron affecting small children differently? We're seeing numbers of hospitalized children under the age of five in- in South Africa. What's going on?

DE OLIVEIRA: So, one thing that we know from the Omicron is that it tends to generate very high viral loads. What it means? It means that the infection and because it's a very transmissible variant tend to have higher level of- of virus replication. And one thing that we knew from children and from the other variants that one of the reasons why they didn't develop disease is the lower level of the virus. So, what we have seen at the beginning is a large number of young children being hospitalized. But these numbers are being decreased as these variants start spreading in the older population.

MARGARET BRENNAN: So, does it affect children differently?

DE OLIVEIRA: It is- because it's a very highly transmissible variant, it tends to cause a high number of infections in children. At the moment, it's difficult to tease if the rate of hospitalization of children in the beginning is due to the sheer number of infections in the younger population or if it is because it causes more severe disease. But one thing that we see is that the younger population presenting to the hospital is decreasing over time, especially in the last few days.

MARGARET BRENNAN: You have said that the Omicron variant probably incubated or mutated inside the body of a person with a suppressed immune system, possibly someone with HIV. Are you seeing a higher rate of infection among those who are HIV positive?

DE OLIVEIRA: OK, so- so let's be very clear, what we know from variants, we know we learned that from the alpha, potentially on the beta and the Omicron, that they have signs of being evolved immunosuppressed individuals. Because the Omicron emerged in Johannesburg, which is to South Africa, it's what Atlanta is to the United States of America, the biggest international airport, the biggest one in the continent. It means that this variant could have come from anywhere else and was amplified in Johannesburg. So at the moment, our suspicious and not only our one, but the top evolutionary biologists of the world, is that these have sign of being developed immunosuppressed individuals such as cancer patients or patients that they get to, for example, transplant or HIV immunosuppressive individuals. In relation to the HIV population, we know two things, that HIV first is not the problem, because if you are HIV positive and you are viral suppressed- the viral suppressed individuals on antiretroviral therapy to respond as an infected person. What it means is that it will clear the virus of SARS-CoV-2 and they are less likely to develop disease. But what we know from people that are HIV and not on antiretroviral therapy successfully is that they're going to stay longer infected and they're going to have a worse clinical outcome. And that's not only specifically to HIV, but any kind of immunosuppressive disease, such as cancer.

MARGARET BRENNAN: Do you believe that you are past the peak of infection in South Africa because recent trends are suggesting there's a slowing?

DE OLIVEIRA: So- so we- we do not know, and one should always be very careful to look at the individual day- daily tests. What one has to do is to look at the general trend of seven or 14 days. What we know is that last week we were adding the highest number of infections from Omicron. And what we are going to be doing is looking very carefully at that data, potentially halting and Johannesburg may have peak. But what we have seen is that this has spread for the other eight provinces. South Africa has nine provinces, which, like similar states in America and in all of the other eight provinces, the numbers are increasing and increasing very fast.

MARGARET BRENNAN: Before I let you go, at least two dozen countries have travel restrictions on South Africa. Dr. Fauci here in the US said America would like to lift it as soon as they have evidence to justify it. Do you believe the travel ban can be safely lifted now?

DE OLIVEIRA: Yes, of course. First, travel bans they do not work and you're going to remember one of your previous presidents that was the first one to put that travel ban to China and the United States of America and ended up with the higher number of infected individuals of SARS-CoV-2 and with the highest death toll in the in the road- in the world. And not only travel bans do not work, but they also will discourage scientists like us that have been brave enough to identify a variant that has emerged like a week or two after it emerged. But it will give the chance that countries and scientists, when they identify variants, they decide not to come public which would be the worst thing for the global pandemic. I personally have talked to Tony Fauci many times in the last few weeks, and we both agree that not only that travel bans should be released because they are not effective but will discourage the rest of the world to become public with key crucial data that can help the response to the pandemic.

MARGARET BRENNAN: Doctor, good luck with your research. Thank you for your time today. We'll be right back.