The Learning Blog

A few weeks ago, Dr. Vincent Racaniello, one of the hosts of This Week in Virology (TWiV), a podcast of  viruses “that make you sick,” went to his son’s high school to talk about the science of viruses. With his permission, I transcribed several questions from the students and teachers and, of course, Dr. Racaniello’s answers. I have also included the introductory portion he gave from his podcast. I hope you can learn from his explanations as much as I did. Note: This is not a word-for-word transcription, I had the liberty to clean up the conversations so as to be more understandable.

INTRODUCTION

Several weeks ago, I visited my local high school, Scotch Plains-Fanwood High School, and taught Virology to the Biology classes there. My motivation to do this was two-fold. First, my older son … had asked me to visit his class and talk about viruses. In addition, on an earlier TWiV, a listener had suggested that I try to engage high school students on a podcast by including some of them. So I took that advise and scheduled a day of teaching high school students about viruses. I contacted my son’s biology teacher … who asked if I would also teach other classes besides her. In the end, I spoke with seven different classes of AP and accelerated Biology students. I gave them an overview about viruses—what they are, how they propagate, and how we study them. Then I spoke briefly about the 2009 H1N1 influenza virus strain and the vaccine against it…. At the end of each period, I had the students ask questions about viruses which I then recorded along with my answers. Those sessions formed the main part of this podcast. I think you will be very interested to hear what great questions the students asked. Their curiosity comes through clearly and their concerns about the H1N1 vaccine mirror those that I’ve seen in the general population. I also spent a few moments speaking with [the] biology teacher who helped arranged the day…. At the end of the day, I was exhausted and had new-found respect for high school teachers. I also felt that I probably should have spoken less and engage the students more. I’ll keep those lessons in mind in a few years when my other children are in high school and I return to teach them about viruses….

QUESTIONS AND ANSWERS

Question #1

I was wondering if you can speak to us—there’s a lot of people in the news, famous people, that are rallying against vaccination–in particular, MMR and getting children vaccinated. And the latest data is that the data for that was not so great. So I was wondering if you could just kind of clear that up for anybody that might have a misconception about the MMR vaccination in kids.

Answer #1:

That’s a tough question. So [he] is asking me why famous people are saying we shouldn’t receive vaccines.

What this originates from is the report in the late ‘90s by a British physician whose name is Andrew Wakefield, who studied about 10 children with autism, a developmental disorder of children which is manifested very early in life. And he claimed that shortly after these children received the MMR vaccine, they developed autism. MMR is measles, mumps, rubella. It’s combined three viruses combined into one vaccine. So he said what happened in these kids—they got injected with the vaccine, the vaccine virus went to their intestines, it grew in their intestines, and made their intestines permeable so that the children were taking up toxins from the environment, and that’s what caused the autism.

So to make a long story short, his study was flawed and, subsequently, ten different epidemiological studies were done to see if there was any correlation between immunization with MMR and the onset of autism, and there was none.

In an epidemiological study, what you do is you study many, many kids. You have half of them get the vaccine and half of them don’t, and you compare the rate of autism on both populations. And if the vaccine causes 1 in 15,000 cases of autism, you’ll see it. Of course, the proponents of “no vaccine,” [they say] it causes autism in all kids and is never detected. So this was taken up by famous people, in the press, and—I mean, of course, the problem is parents whose children were autistic want to know why they became that way. We don’t understand autism at the moment. So it’s very convenient to blame the vaccine. But I can tell you that there is zero evidence that these vaccines, or any other vaccines, were responsible for autism.

Unfortunately, the result is that, especially in the UK, immunization rates with MMR went way down. There were outbreaks with measles and measles can kill. There were a couple of deaths in England, totally preventable.  But because there was a false idea that these vaccines were dangerous, this happened. To this day, immunization rates have never recovered in the UK. No vaccine causes autism. There’s zero evidence. They’re all pretty safe. No vaccine is totally safe; there are always side-effects. If you get the flu vaccine you get swelling, you may get a little fever, but they don’t cause autism for sure. That’s the short answer.”

Question #2:

You said how the HIV virus can never be eradicated. So how did they eradicate the smallpox virus and polio in the beginning of the 1900’s if we can’t do it with HIV?

Answer#2

That’s a great question. So the problem with the HIV is that the viral RNA—when the virus infects cells, it gets converted to DNA and that DNA gets integrated into your cells. So you can get rid of the virus in a person by treating them with antiviral drugs. That’s why many people live for ten years or more with AIDS now because the antivirals make you disease-free but the DNA is still in your genome. So you can never get rid of that and from time to time it can produce new virus particles. So that kind of lifestyle isn’t present for smallpox or polio. Once you get rid of those viruses from a host, they’re gone. There’s no DNA left behind in the host. And that’s the real problem with HIV that we don’t know how to get rid of that DNA from our cells. People are working on it but until we figure it out, we can’t eradicate it.

Question #3

There are different viruses that are more susceptible to medications than others. So for HIV, there are some strains that we have better treatment for than we do with others. I had also read a story a few years ago about applying natural selection to this process where we can treat for some so that the ones that were more susceptible will come back in greater numbers and then we could really hammer those with the drugs that we have. So it’s kind of giving people a treatment for a period of time and then taking them off the treatment for a period of time to increase the counts of the virus that’s more susceptible to the drugs and then whack them really hard with the drugs and kind of working off and on with a cycle like that. I’m just wondering if you could speak to us about that.

Answer #3

All right, so what he’s referring to is a treatment of a number of years ago. So we have a lot of antivirals against HIV. These are drugs that you can take which will block replication. One of the problems is that you get resistance to these drugs very quickly when you take them. And about ten years ago, we were treating one drug at a time and within a couple of weeks you get resistance. So the idea was to treat with drug and then stop—let the viruses grow back and then treat again. And the idea would be that the susceptible viruses would grow out and then you could knock them off. Unfortunately, this is a great way to get resistance. So we don’t do that anymore. It’s a bad idea and it’s not done. What we do now is we treat people with three drugs at a time, it’s called “triple therapy” and it takes a couple of years to get resistance to all three drugs. And when you do get resistance, you just change the combination. So, you know, Magic Johnson has been living now over ten years with AIDS because every two years they switch his combination of drugs. Now we have about 20 or so drugs,right? So you have seven different combinations you can use theoretically and then you’re out of luck. But, hopefully, in the meantime, new drugs are developed and there are always new ones. So with disease, the extent of HIV, there’s always new drugs that are being developed. So we identify new targets in the virus, new enzymes that we can inhibit, and pharmaceutical companies are always new ones. So now the regimen is to use combinations and not do the—it’s called “interrupted treatment.

Question #4

How would you compare viruses to prions?

Answer #4

A prion is a protein that seems to be infectious. So there are prion diseases like Mad Cow Disease where you could eat contaminated beef—it has a protein in it, that will make its way into your brain and cause neurological diseases. So when prions were first discovered, the only people who paid attention to the prion scientists were virologists. Because we were the only ones that appreciated that this could be.

So a prion has no nucleic acid. It’s just a protein and it’s infectious. It’s different from a virus because all of our viruses that I have told you about have nucleic acid genomes. Prion is just a protein. And what happens is this protein goes into your cell and it makes other proteins like it misfold and they become disease-causing. So if you ingest a prion, it will induce a disease in you by making your proteins misfold. So it just goes to show that you don’t need nucleic acid to be infectious. A protein by itself can do it. So if you have heard—you know, sometimes beef gets contaminated with prions and it can’t be sold. This is what the cause is, these infectious proteins.

Question #5

You said viruses can be spread through contact, so how long—like I sneeze on a door knob—how long will it take until like a guy couldn’t get it?

Answer #5

Influenza virus, for example? About a couple of days it will last on a door knob.

They’ve done studies in Day Care Centres where you have all these hard plastic toys and the virus can last a few days on the toys. Of course, it varies from virus to virus, but flu is the most important, most likely. So you have to be very careful. You should wash your hands a lot.

When you’re in a school like this, this is a great place to spread flu. As soon as school resumed this fall, flu rates shot up, right? So in the summer, everybody’s scattered, there’s not much interaction. But this is a great setting because you’re in one room, and you don’t have to sneeze, like I showed you, to make great aerosols. I am making an aerosol right now talking. You’re all making little aerosols breathing and that’s where viruses are coming out. So if one of you has flu in a room like this, you can easily infect everyone else. So it’s not just the touching, but you have to remember that if you’re ill you should stay home—I’m sure that’s not a problem with you guys—and if you’re touching in the school lots of things, you should wash your hands before you eat lunch or touch your face. It’s really important.”

Mind you, what I’m sharing with you now is just the tip of the iceberg, there are lots more from this particular TWiV episode.

If you wish to know more about viruses, you can visit the TWiV homepage (for free!) by clicking here. For the “Virology in High School” episode, click here.

Just want to share this link for those who are very much interested in knowing the influenza viruses.

It is more or less a detailed view on what this viruses are: their structure, how they infect our body’s cells, how they replicate, and many more.

The author, Dr. Vincent Racaniello, is a virologist and professor of microbiology at Columbia Medical Center. He also is one of the hosts of the weekly podcast This Week in Virology talking on the facts, figures, and experiences of important viruses that can influence our daily lives.

Influenza 101 is an on-going learning experience, so I hope you visit the site once in a while to check out for new topics.

Better be late than never. Although the news media had been in some ways (but not all the time) overhyping the recent flu outbreak, let’s get things straight. I am presenting some facts and ideas from an interview a month ago between Dr. Vincent Racaniello and Dr. Peter Palese. I’ll be updating and/or adding more information in the near future.

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