It's been about three years since the World Health Organization announced that the Zika virus and its possible link to birth defects was an international public health emergency. Eli Rosenberg of UAlbany's School of Public Health describes his ongoing efforts to study the disease with The Dengue Branch of the U.S. Centers for Disease Control and Prevention in San Juan, Puerto Rico.
It's been about three years since the World Health Organization announced that the Zika virus and its possible link to birth defects was an international public health emergency. Eli Rosenberg of UAlbany's School of Public Health describes his ongoing efforts to study the disease with The Dengue Branch of the U.S. Centers for Disease Control and Prevention in San Juan, Puerto Rico.
The UAlbany News Podcast is hosted and produced by Sarah O'Carroll, a Communications Specialist at the University at Albany, State University of New York, with production assistance by Patrick Dodson and Scott Freedman.
Have a comment or question about one of our episodes? You can email us at mediarelations@albany.edu, and you can find us on Twitter @UAlbanyNews.
Sarah O'Carroll:
Welcome to the UAlbany News Podcast. I'm your host, Sarah O'Carroll. It's been about three years since the World Health Organization announced that the Zika virus and its possible link to birth defects was an international public health emergency. I have with me Eli Rosenberg an associate professor of epidemiology and biostatistics in the School of Public Health. Eli has been working with colleagues from the Centers for Disease Control and Prevention since the outbreak began to research the risk of sexual transmission of Zika. Eli, thank you for being here today.
Eli Rosenberg:
Thanks for having me.
Sarah O'Carroll:
Can you give us some sense of the magnitude of the problem of the Zika virus today? Just how many countries are we talking that have reported infection? Is it growing, going down?
Eli Rosenberg:
Yeah, so you started with the introduction that this was announced three years ago and really the problem's been mostly over for two years. So Zika really swept through the Western Hemisphere in 2016 and subsided by the end of 2016 and into early 2017. So today not much active transmission is going on. I was just on CDC's website yesterday and really it looks like there's only one region of India that's actively reporting transmission. So Zika is not an issue right now, but the real concern is in the future, if and when it should come back.
Sarah O'Carroll:
Okay. So what are some common myths or perhaps what are some common misperceptions about the Zika virus in terms of its transmission and affects and how might you clarify those?
Eli Rosenberg:
Sure. At the outset of the Zika epidemic, there was a lot of uncertainty of around how exactly the virus could be transmitted. Everyone knew that mosquitoes were a big part of it, but we also had a suspicion based on other evidence that there was clearly mother to child transmission going on, that there was sexual transmission and perhaps some other modes of transmission.
Eli Rosenberg:
And so it was really important at the outset to launch a variety of studies, which is what we were part of, to really tease out how much these different modes of transmission mattered and what the risks were for and for how long could people transmit by these ways. And so that was really the purpose of our projects.
Eli Rosenberg:
And I'll say that one of the things that our most recent publication found was that the risk of sexual transmission was much higher, like probably much higher than people had thought. So we had originally been thinking that it was more of a rare occurrence and sort of very high profile situations we saw sexual transmission occur. But it turns out that an areas even when there was mosquito transmission going on, sexual partners were at significantly elevated risk of acquiring from their partners. So a sexual partner was about twice likely to acquire Zika compared to a nonsexual partner.
Sarah O'Carroll:
Okay.
Eli Rosenberg:
So the risks, so even though we were focusing on, if you were in an airport, it was about wear mosquito repellent and you know, sort of mosquito prevention. But clearly sexual transmission was another thing to be thinking about as well.
Sarah O'Carroll:
That's really interesting and troubling. Now can you share a little bit about your process? From my understanding, you were in Puerto Rico working with a CDC branch there?
Eli Rosenberg:
Yeah.
Sarah O'Carroll:
So what were you studying specifically in terms of how Zika is transmitted sexually?
Eli Rosenberg:
Sure. I'll first say that the sexual transmission work was going on as part of a larger project. That was sort of one sub analysis that we did as part of a larger cohort study. So a cohort study is when you enroll many people and follow them over time to understand many outcomes. And so what had happened was, so CDC has a branch in Puerto Rico called the Dengue branch. And Dengue and Zika viruses are actually very similar and also spread by the same mosquitoes. So it was sort of a natural place for the US to be understanding these issues. It also happens to be the Puerto Rico was where the overwhelming majority of the United States cases of Zika virus were, so. And through the end of 2016 they saw about 35,000 diagnoses of Zika virus.
Sarah O'Carroll:
Wow.
Eli Rosenberg:
Compared to just a few hundred in the United States from local transmission and then some more from travelers who had come back to the mainland United States.
Eli Rosenberg:
So I think one thing to point out is that we forget how much of the burden of this epidemic was really in Puerto Rico and the United States. So we were very well positioned to do this work. There was already a CDC office there. And at the outset of the epidemic in early 2016 there was a number of new projects were launched to understand what was going on. And there were two cohort studies started to understand the longterm implications of infection.
Eli Rosenberg:
One was this one in Puerto Rico called the zipper study and the other was among male travelers who had returned to the United States and were infected. And they were enrolled in a separate US project. So those were the two US projects to understand really what happens in the weeks and months following infection. Because we knew that sort of the short term what happened with Zika virus, but we didn't know how long people could stay infectious. And so what would happen to their symptoms over time.
Eli Rosenberg:
There were other projects launched to understand the longterm implications in pregnant women and then in their unborn offspring and then after birth their children. So that was a separate wave of projects.
Eli Rosenberg:
But that together was sort of how the public health infrastructure of the country circled around to understand these issues.
Sarah O'Carroll:
Now what were some of the questions that were answered and what questions still linger?
Eli Rosenberg:
That's a great question. So this project was really about understanding what happened to all adults who might be infected over time. And then as part of that, we looked at sexual transmission and did sort of special analysis where we really looked at the sex partners and what was going on. But we were more generally trying to understand how long Zika remained in the blood, how long it remained in the urine. And those were important for understanding diagnostics and transmission.
Eli Rosenberg:
So there's a lot of questions still unanswered. And the real challenge is that Zika is gone. So if you want to study this further in humans, we have a real challenge. I'll just say that during the epidemic, a number of vaccine trials were launched that could not reach their enrollment because the epidemic ended. And so now we're stuck with incomplete evidence about a vaccine.
Sarah O'Carroll:
That's just interesting that all you have is the people who were infected versus studying the virus itself.
Eli Rosenberg:
That's right. So what's left now is looking at more laboratory studies, animal studies. But the opportunity to study in humans is sort of over for some time. So we're sort of left with the data we collected then, which is why when we looked at sexual transmission in our work, we were only able to take it so far from our data. And you wish you can start a new project to understand more.
Eli Rosenberg:
And so what I mean by that is we looked at sort of the relative likelihood that a sex partner would become infected. So it was about two fold. But that leaves that we still don't know per sexual encounter what's the risk? What's the preventative value of using condoms? How much do certain other sexual decisions matter? We couldn't even necessarily fully tease out was it the fact that people were sex partners or did they share a bed. There's sort of other co-occurring factors. Maybe it's the proximity of sharing a bed. And the reason is that mosquitoes will surely feed off of people who are in the same home. And so it could have been that it was actually mosquito transmission, but it looked like people who happened to be sex partners were the ones that were getting infected because they were-
Sarah O'Carroll:
In the same house.
Eli Rosenberg:
In the same proximity with the same mosquito.
Eli Rosenberg:
So there's all these things you want more data to tease further and we can't. So that's the real, you know, with these sort of outbreak situations, you capture the data you've got as best as you can in the moment and you're stuck.
Sarah O'Carroll:
Is there any guidance that you have for people going about their daily lives who have been to Puerto Rico or other places that had the Zika virus in the country? Is it something that there should be a conversation of asking a potential partner if they've been tested for that?
Eli Rosenberg:
I'd say the first thing is CDC maintains a really good website that sort of has sort of what are the active areas of concern and what to do. So that would be my first thing to sort of check with where the current alerts are for this. Generally, we're talking about areas, you know, sort of a warm climates near the equator where the types of mosquitoes, Aedes aegypti, live.
Eli Rosenberg:
But in general right now we're talking about pretty low risk. That's not to say that the virus is not going to re-emerge in the coming years. It probably will for reasons we can talk about. But right now the risk is rather low.
Eli Rosenberg:
That being said, other viruses like Dengue virus they're still active, Dengue outbreaks at different parts of the world in different times, and they're spread by the same mosquitoes and Dengue is not very fun either. So travelers to sort of these areas should generally always be checking public health websites.
Sarah O'Carroll:
For public health officials, how might they benefit from your research or perhaps already have used this research?
Eli Rosenberg:
Yeah, great question. So aspects of this work were incorporated into various updates of the recommendations that the government puts out. So you know, in the early days of the epidemic there was very interim guidance that was provided to the community and to clinicians around key aspects of Zika.
Eli Rosenberg:
So what I mean by that is how long you should advise a woman looking to conceive to abstain from conceiving to make sure she wasn't Zika infected. How long should sex partners abstain from unprotected sex after being possibly exposed to Zika virus. So some of these issues were originally the guidance was originally based on very thin data and some of the findings from different papers from this project were used to update those findings. Particularly around the delaying of pregnancy or not. And then around how diagnostics should be done. So which specimens from the body should be tested. And then also some of the findings were used to affirm that men who have been exposed can resume sexual practices after about three months.
Sarah O'Carroll:
Okay.
Eli Rosenberg:
So the data were used to inform those three areas.
Sarah O'Carroll:
What else have I not asked about that you might want to include or any other findings or guidance that you might have?
Eli Rosenberg:
I think just one thing is just that our attention as a public, you know, there's so much going on in the world. And even in Puerto Rico right after, after Zika in 2016, there was two large hurricanes that came through and devastated Puerto Rico. And naturally all the attention turned to those issues. But the threats from mosquito borne viruses and other public health issues are always still there in the background. And we get distracted as a public and funds get diverted left and right by our government. And we forget the issues. We forget Puerto Rico. But the fact is is that these epidemics are still going to occur again. So what's going to happen is over time the community's immunity to Zika will lower. So once you get infected with Zika, you don't really get it again. But over time more people will be born and there's likely to be another massive outbreak in the coming years. As there are periodically that Dengue as well.
Eli Rosenberg:
And we need to sort of invest now in the public health education, the research, and just focus our attention on these issues so that we're prepared the next time. Because as I mentioned at the beginning there were 35,000 diagnosed persons. Many of those were pregnant and indeed many children were born in Puerto Rico with various birth defects. And so there's a real public health consequence to not being prepared and so that we can't sort of forget in these coming years to invest in the research. Even if we don't have humans to study that there's still important laboratory work and public health measures to take. And preventative measures at the community level, we can sort of prevent, we can sort of get rid of the mosquitoes. And some of those are underway in Puerto Rico already, but we need to sort of keep that focus so that we don't see a resurgence in 10 years. I think that's really important.
Sarah O'Carroll:
A lull does not mean research should stop. That means kind of this is the preparation stage.
Eli Rosenberg:
Yeah. Yeah, that's always the challenge with public health is we're trying to prevent, and sometimes we're working in the backgrounds right, if something doesn't happen, that means there's success, you know? And so we have to keep that success of keeping something from not happening. And that means we're sort of working like under the headlines in the news and not in the forefront, but we need the public to care and we need people to invest and we need the government to invest in sort of keeping things not visible.
Sarah O'Carroll:
Absolutely. An important topic indeed. Eli, thank you so much for being here.
Eli Rosenberg:
My pleasure.
Sarah O'Carroll:
Thank you for listening to the UAlbany New Podcast. I'm your host Sarah O'Carroll and that was Eli Rosenberg an associate professor in UAlbany School of Public Health. You can let us know what you thought of this episode by emailing us at mediarelations@albany.edu and you can find us on Twitter at UAlbanynews.