Sarah George, MD, Infectious Diseases, at St. Louis University, Center for Vaccine Development talks about the effect Zika has on babies, and how a vaccine could protect future mothers and their children.
Interview conducted by Ivanhoe Broadcast News in March 2018.
Tell me a little bit about what the Zika virus is.
Dr. George: Zika is a virus transmitted to people by mosquitoes and transmitted sexually. It originates in Africa but over the past several decades has spread around the world and it was responsible for a major outbreak affecting millions of people in Central and South America just a couple of years ago.
People are just hearing about this because of the outbreak a couple years ago but this certainly isn’t a new virus right?
Dr. George: It’s not a new virus but it caused a major outbreak in Central and South America affecting millions of people just a couple years ago. Unfortunately during that outbreak babies were born with congenital Zika syndrome which unfortunately was very damaging for the baby. Brain damage, eye damage, and lots of different problems were seen.
Tell me what the risk is particularly to babies.
Dr. George: That’s still under assessment. The rates may be as low as five percent or substantially higher. It depends on a lot of factors like how early the mother was infected in her pregnancy.
What happens if the mother is infected and the baby is born, what are some of the problems that the baby can be born with?
Dr. George: If the mother is infected particularly in the first three months of pregnancy sadly the baby is at risk for being born with severe brain damage. Something called microcephaly where the brain never develops properly and the skull actually collapses because there’s not enough brain tissue to hold it up. They also can be born with eye damage, hearing loss, and they can be born with skeletal deformities, club foot and things like that.
Is there a number when the outbreak happened a couple of years ago how many babies were affected by this?
Dr. George: It was at least several thousand in Brazil alone and more than that in Central and South America.
You mentioned it depends on when you’re infected during the pregnancy, so if a mosquito bites you and you get the Zika virus it doesn’t necessarily mean that your child will have any problems.
Dr. George: No it doesn’t necessarily mean that your child will have any problems. It does mean that you need to get close monitoring during the pregnancy and be followed very carefully by your doctor. The risk is highest if the woman is infected in the first three months of pregnancy which is when the baby is undergoing a lot of critical organ development. Later on in the pregnancy the risk is lower fortunately.
How would someone know if they were infected with the virus?
Dr. George: Fortunately, we have had very few cases of Zika transmission in the United States this past year. There were cases that occurred in people returning from countries where Zika is being transmitted and then there were cases that were transmitted in Florida and Texas which having very southern climates have mosquitos year around.
So an adult doesn’t show any symptoms?
Dr. George: Very few adults (maybe 20-25%) show symptoms. If they do have symptoms it’s only a fever and a rash and maybe some red eyes or sore joints for a few days but most adults don’t even have that.
For these women a couple of years ago there must have been some panic. Like I want to be tested but certainly that’s not cost effective so what’s the balance there?
Dr. George: The mosquito that transmits Zika is not common in the United States though we do have it in the Southern United States and there were some mosquito transmitted cases in Florida and Texas. For women in America unless they’ve traveled to a Zika transmission area their risk is extremely low. So low you can’t even put a number on it. For women who are living in areas where Zika is being transmitted it’s obviously more of a concern.
Is there a reason behind the outbreak, why so many a couple of years ago, what was the reason behind this outbreak?
Dr. George: We’re still working that out. We think in large part it was just because Zika had never been seen in those countries before. So you had hundreds of millions of people who had no immunity to Zika. And then all of a sudden it got introduced and it spread throughout the population. Same thing happens when we get a new form of flu about every ten to fifteen years. People don’t have immunity so it just spreads through the population.
For non-pregnant women are there risks of this?
Dr. George: The only risk for non-pregnant adults that we know of, they can get a rash, fever, aching joints, and red eyes, that’s uncommon. And then we are seeing some adults come down with Guillain-Barré syndrome which is a neurologic syndrome where they get a temporary partial or even complete paralysis. But the prognosis for that is quite good, they usually recover completely.
Without treatment?
Dr. George: They get treatment in a hospital for it. There are various ways we have for treating Guillain-Barre syndrome. Most people recover from it completely.
Tell me about the need for a Zika vaccine.
Dr. George: We certainly need a Zika vaccine even though the case numbers have dropped off dramatically over the past year which is good, but it’s going to come back. It’s in the mosquito population and based on the changes in the mosquito population or when we have another group of people who are born and not immune to Zika we will have another Zika outbreak. We just don’t know when or where.
Tell me a little bit about your research.
Dr. George: What we are doing here at the St. Louis University Center for Vaccine Development is we are doing one of four different studies with an inactivated Zika vaccine which was developed by Walter Reed Army Institute of Research. The vaccine trial was sponsored by the NIH, National Institutes of Health, and again it’s one of four different trials that are going on with this vaccine. We are studying how this vaccine works in terms of safety and antibody responses in about ninety healthy adults.
What have early results shown?
Dr. George: The early results were published a few months ago in Lancet which is a medical journal and they showed that so far we haven’t seen any safety issues. The vaccine seems safe so that’s very important and it is inducing an antibody response to Zika.
What does that translate to for us, for the general population?
Dr. George: It translates that based on the data so far this is a vaccine with good promise. There are a number of other Zika vaccine candidates being evaluated. They’re all coming through the pipeline. Ultimately of course what has to be done is we have to determine whether or not this vaccine or any of them protect against Zika virus and Zika disease.
So far it looks promising that it does protect?
Dr. George: So far it’s safe and it raises antibodies against Zika.
Is the goal for this to be in countries affected or in South Florida or in some of these warm climates? Is the goal for pregnant women to receive this? Or would whoever wants to receive it get it, just like a flu vaccine?
Dr. George: A lot of that remains to be seen but the goal is to have a vaccine for people in areas where it’s being transmitted and then areas of risk which as you say are South Florida and South Texas in this country. You might want to give it to young girls so that they have antibodies before they could ever become pregnant; that all remains to be worked out. For example, we have the measles vaccine, the MMR measles vaccine which we’ve been giving to children since the 1960’s. In addition to protecting you against measles, that protects pregnant women against getting rubella during pregnancy and having a baby with what is called congenital rubella syndrome or congenital measles which could also be just devastating in a pregnancy.
This would not be a yearly vaccine, the intention is for this to be once or twice, maybe a booster?
Dr. George. That is the hope; again, it remains to be seen. The vaccine we’re testing is two doses, some of the others being tested are three doses and maybe even more than that. We don’t know the answers on that yet but the hope is this would be just a one or two time vaccine. Not an annual one like the flu shot.
Will there be different strains of this?
Dr. George: There are different strains of Zika. It doesn’t seem to be as mutagenic or if you will unstable a virus as flu. Remember there are different types of flu every year so we need a new flu shot every year. Zika seems to be a bit more stable so if we can make a vaccine maybe that will be enough. It remains to be seen. It’s early days yet.
How important is this?
Dr. George: This is very important. The Zika outbreak caused a lot of babies, thousands of babies in Central and South America to be deformed. To be born very, very deformed. That was devastating for the parents and the babies sometimes died. Or they had to raise a baby with a lot of health issues and health problems that are going to be lifelong. You know pregnancy is usually a wonderful thing, nobody wants to be told, I’m sorry there’s something seriously wrong with your baby. Everyone wants to be protected against that and if the vaccine can do that that’s wonderful.
It’s crazy it’s from a mosquito.
Dr. George: There’s a lot of mosquitoes out there and they carry a lot of diseases and Zika is one of them. Dengue is another that we don’t fortunately have much of in this country. There’s West Nile that is transmitted by a different type of mosquitoes in this country. Mosquitoes transmit malaria in the tropics, they’re nasty pests.
I read somewhere where the question was ‘what’s the deadliest animal or life form on the planet.’ The answer was mosquitoes, it kills more people.
Dr. George: I would believe that.
Anything else you think we should talk about?
Dr. George: We do a lot of very important work on a lot of vaccines here at the Center for Vaccine Development and we’re very proud to have this study that was sponsored by the NIH using the vaccine made by Walter Reed Army Institute of Research.
This study was published in the Lancet; were you the principle investigator here, was this the principle or were you one of a few sites?
Dr. George: We were one of several sites. The study in the Lancet discussed three of the four studies and was the interim data from three of those four studies.
How many volunteers did you have here?
Dr. George: We have a total of ninety and we’re following them for a year after vaccination.
END OF INTERVIEW
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