The voice behind the popular Virology Blog talks about the Ebola response
Vincent Racaniello Ph.D., a Professor of Microbiology & Immunology in the College of Physicians and Surgeons of Columbia University, has been studying viruses for over three decades. But he's perhaps better known for his Virology Blog, which he uses to educate people about viruses and viral disease. His topics cover a wide range of pathogens, from a polio-like virus in California to the unusual mortality patterns of the 1918 Spanish flu pandemic. Lately, his blogs have been heavily focused on Ebola; most recently he weighed in on the conflicting opinions about Ebola quarantine policies. Senior Scientific writer Regina McEnery spoke with Dr. Racaniello last month to talk about filoviruses and the public health response. Here are his edited responses.
You obviously get asked a lot about Ebola. What is one question that you aren't being asked that needs to be addressed?
The first thing that popped into my head—nobody asks me how we are going to stop this current outbreak? Ideally, the best way is to have a vaccine and to do ring vaccination, but we don't have a vaccine, and I am not sure when we will. The World Health Organization (WHO) says by the end of 2015 we will have a million doses, assuming the current vaccines are safe and work. Right now, countries are building tent isolation hospitals. I think that is feasible—getting people into proper isolation units so they don't stay home and transmit [the virus] to others—though the health care personnel that will be needed to staff the units will have to come from other countries.
Speaking of health personnel, there was a lot of controversy recently over how New Jersey handled the return of a nurse from Sierra Leone. Do you think the state's 21-day quarantine is overly strict?
It's not what the CDC recommends but unfortunately the situation has become politicized. I read in a NJ newspaper recently that a Nobel Laureate [Bruce Beutler] believes it's the right thing to do because you can't be sure if Ebola can be transmitted during the incubation period. He's a Nobel Laureate and so the general population feels he is right, but I think he's wrong and I don't think he has read the literature. In all of the previous outbreaks of Ebola, transmission occurred after close contact with either an infected individual or with bush meat [contaminated with Ebola]. In fact, one study [from a 2000-2001 outbreak in Uganda] followed a bunch of health care workers who were symptomatic for Ebola and took daily blood samples. On the first day of symptoms, virus could be detected just above the detection threshold, but viral loads increased thereafter and much faster in those who died of Ebola. And even with the Dallas patient, when he was living at home, didn't infect anyone. It was just the health care workers who treated him that become infected.
Is it harder to develop vaccines for filoviruses than for retroviruses?
No, not at all. We know antibodies correlate with Ebola protection, but in HIV we still don't know what the correlates of protection are. And it's technically easy to put glycoproteins in viral vectors. The hardest part is doing the animal challenge studies because you need to do them in a BSL-4 [high containment] laboratory. People have been calling to shut down all these labs, but we couldn't have gotten this far without them.
How do filoviruses compare to other viruses in terms of their diversity?
From what I can tell, they do not evolve as much as influenza viruses. All the sequences in this current outbreak of Ebola were derived from a single introduction in animals, way back in December of last year. With all viruses, there is some diversity as they move from host to host, but I have not seen any mutations arise that would suggest this strain is spreading any differently than before. It's just garden-variety Ebola. Humans are not the real host for this virus so in most cases, it just fizzles out.
Is there anything about the current outbreak that has altered your thinking about filoviruses, and Ebola in particular?
Two things have struck me. The first is that in all previous outbreaks we were able to limit the virus' spread pretty easily. We were able to trace every contact and work back to the index case. When I first heard about this outbreak I assumed that it would be the same. I'm surprised it got to this point, but it's a good lesson.
More importantly, and what I think is amazing, is that we have been saying for years the case fatality ratios of Ebola are high—between 30% and 80%. That seems entirely due to the health care systems in the countries where the outbreaks occurred. If the outbreak had occurred in the US, the case fatality would probably have been less than 10% because we know how to take care of the patients. That tells me the virulence is not the function of the virus, but it really is a matter of how you treat the patients.
How do you think the global health community has responded to the outbreak and what would you have done differently?
I think the CDC [Centers for Disease Control and Prevention] has done a good job of putting info out there, but Tom Frieden [the CDC director] screwed up early when he said they were prepared and they weren't so no one trusts him anymore. And probably no one will trust the WHO either. The lesson here—if you make an error early on you will lose people's faith. The CDC has a long history with diseases. I find a lot of useful info on the CDC's website, but most people don't go there or don't understand it because it's too technical. That is where scientists have some role. We can do our own communicating but we can only reach certain people. Also, a lot of scientists speak independently and say the wrong thing and end up scaring a lot of people.
Photo of Dr. Vincent Racaniello in HazMat gear, courtesy Dr. Vincent Racaniello, used with permission.