Tag Archives: Vaccine

Podcast returning next week!

We are pleased to let you know that the PHU podcast will be starting up again next week! I will be discussing vaccine hesitancy with Drs. Heidi Larson and Pauline Paterson who co-direct the Vaccine Confidence Project via London School of Hygiene and Tropical Medicine (among many other cool things!).

Thesis Me Pic
Dr. Nina in the house!

It’s been a long time since the last podcast, but with good reason: on September 1st, I successfully defended my doctoral thesis in molecular microbiology & immunology. I also have completed two manuscripts for publication over the summer. Other great things I was up to:

Summar Collage Pix

  • Got a job! Starting soon: associate at the International Vaccine Access Center on the Policy, Advocacy, and Communications Team! Learn more about IVAC on this podcast with my new boss Lois. Or listen to Bill “heartthrob” Moss here and here.
  • Fellow, New York Academy of Sciences Science Alliance Leadership Training – July 2017. Five days of leadership training at the Academy. Met so many great people and learned so much about myself, how I function in group settings, and things to work on to become a better leader (and group member).
  • Oral presentation, American Society for Microbiology Conference for Undergraduate Educators – gave a ‘microbrew’ talk on my scicomm course. Fantastic conference in Denver, Colorado with fellow educators interested in improving science teaching methodologies. I can’t wait for next year already! July 26-August 1.
  • Completed Teaching As Research Fellowship: June 2017. Completed this yearlong fellowship that provided training and resources to research the effectiveness of my teaching methods in my course, “Communicating Science.” Presented on June 30 at Johns Hopkins University.
  • Awarded Gordis Teaching Fellowship: Johns Hopkins School of Public Health teaching fellowship to design and teach a course to public health studies undergraduates at Johns Hopkins. Taught self-designed course “Communicating Science: Skills to Analyze and Communicate Science News”. Awarded for three semesters: Spring 2016, Fall 2016, Spring 2017.
  • Instructor, Introduction to Biomedical Sciences, August 2017. Taught three classes as part of Dr. Gundula Bosch’s intensive summer course for incoming JHSPH graduate students. Sessions taught: Science Communication, Molecular Biology, Musculoskeletal System, Cardiovascular System. This was my fourth year co-teaching this course and always meet so many fantastic new students.
  • Invited speaker, JHSPH Molecular Microbiology & Immunology Postdoc Forum. July 2017. Science Communication.
  • Invited speaker, Mississippi State University, September 2017. The anti-vaccine movement.
  • Completed Johns Hopkins Teaching Academy “Preparing Future Faculty” Certificate Program, Johns Hopkins University, September 2017. This certificate program provides training in teaching methods for Hopkins graduate students and postdocs. Check out here.

Episode 42: Meghan Moran On Persuasive Communication

 

meghan-moranOur latest guest, Dr. Meghan Moran, researches how the tobacco industry uses persuasive messaging on youths and teens–and how public health policy makers can use that knowledge to implement prevention campaigns. She also uses her expertise in persuasive communication to analyze why people are swayed by anti-vaccine messaging, and that it is not for the reasons we typically consider! Meghan is an Assistant Professor in Health, Behavior and Society Department at Johns Hopkins School of Public Health.

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Get In The Game: Vaccine Communication with Dr. Paul Offit

 

I had the pleasure of visiting my old work place and interviewing Dr. Paul Offit, vaccine communicator and researcher at Children’s Hospital of Philadelphia. What ensued was a very stimulating and often times LOL kind of conversation. I am very thrilled to share this insightful podcast with a leader of scicomm (an often extremely difficult role).

Paul Offit

Download the podcast here or access on iTunes here.

Show Links:
Paul Offit at Children’s Hospital of Philadelphia
Children’s Hospital of Philadelphia Vaccine Education Center
List of Paul Offit’s books on Amazon
Information on rotavirus vaccines
Link to Paul Offit’s free vaccine course on Coursera
Watch Nina at Ignite Baltimore speaking on vaccine communication issues
PBS/Frontline Article: The Vaccine War

 

 

Vaccine Concerns: Synthesis of Vaccine Viruses (Ingredients Part 2B) by Nina Martin

After reading Part 1 and Part 2A, you should now understand why we use medium, FBS, and antibiotics to grow cells and that it’s important to passage cells if you want to continue or expand your cell line. We also discussed fibroblast cells and how they are typically used in the lab because they are easy to grow and you can expand your cell line into multiple flasks rapidly. These concepts are absolutely vital in understanding how vaccines are made.

Let us move on to the next big concept in vaccine manufacturing: attenuation of the virus. You may have already heard the term attenuate. For example, the measles vaccine is a live, attenuated vaccine. What does this mean and how does this fit in with our ingredients list?

To attenuate means to weaken; to attenuate a virus means to weaken it. Remember that for an efficacious vaccine, we want to expose people to the germ and activate the immune system without causing illness. In the lab, scientists have figured out how to change the measles virus so it will still activate your immune response, but not actually make you sick. Here’s how:

Slide3
Virus attenuation via adaptation into a new host cell. 1. Sample is taken from host. 2. Passaged through chick embryos multiple times. 3. Passaged through chicken embryo fibroblasts multiple times. 4. Attenuated virus is isolated from cells and sequenced.

Wild measles virus is well suited for human cells: once you breathe it in, measles will invade your lung (epithelial) cells, take over its machinery, and reproduce itself. A scientist name Enders first discovered that if you add measles virus to non-human host cells, like chicken egg (embryo) cells, the virus will adapt (aka mutate) to its new host. This is survival of the fittest at its best! Please note that the measles vaccine virus used in MMR is passaged in chicken embryo fibroblast cells and not in eggs.

Measles attenuation
Diagram of how measles virus was attenuated. Key: Names within the colored boxes are the names of the measles strains. 1. Measles virus was isolated from a patient with last name Edmonston. 2. The Edmonston strain was serially passaged 24 times in human kidney cells, 28 times in amnion cells, 6 times in chick embryos, and then in chicken embryo fibroblasts to create the Edmonston B strain. The current measles vaccine virus in the U.S. (Attenuvax, Merk) was made by further attenuating the Edmonston B strain 40 times in chicken embryo fibroblasts. We call this live, further attenuated virus the Moraten or Edmonston-Enders strain.  The Schwarz strain, made by attenuating the Edmonston A strain, is widely used in vaccines in Europe and other countries around the world.

 By repeating the process of adding virus to cells, letting it grow, then isolating the virus and adding it to a new plate of cells, over time you can create a virus that is so well adapted to surviving in its chicken host that it can no longer efficiently reproduce in the human host. We call this process passaging the virus in cells or tissues. Please read our previous article for a nice summary of how we passage cells in the lab. The measles vaccine virus is passaged in chicken embryo fibroblasts while other vaccine viruses, like rubella, is passaged in other host cells like monkey kidneys or human diploid cells (more on this in a bit). Theoretically any cell that is not the typical cell for measles invasion could work–though some viruses will not grow at all in certain hosts. It’s important to know that we passage the virus at least 40  times (or even more depending on the specific vaccine) in chicken embryo cells. This is necessary (and great) because when you give the attenuated (weakened) virus back to the human host, there is only an extremely small chance of it reverting back to the wild virus—each round of passaging created a new batch of mutations that helped the virus survive in the chicken. It is almost impossible for the virus to jump back to the human-disease causing form.

Rubella attenuation
The rubella virus vaccine strain currently used in the U.S. in the MMR vaccine (Meruvax II) was created by serially passaging rubella virus in WI-38 cells at a low temperature (for viruses). Growing the virus in the diploid cells at low temperature resulted in the production of the avirulent (attenuated) strain RA 27/3.  Two other strains were previously used in vaccines in the 1960’s and 70’s (HPV-77 & HPV-77/DEC but were continued due to side effects and because they didn’t provide as much protection as the RA 27/3 strain did.

 So now when you see non-human cells listed in the vaccine package insert, you know why: wild virus is passaged in non-human cells many times, forcing it to adapt to the new host and no longer causing disease in the human host.

Common concern: Use of chicken embryo fibroblasts to passage virus Some people have legitimate concerns about vaccines that are prepared in chicken embryos. After isolating the virus from the egg, there still could be a small amount of chicken proteins that some people have an allergic reaction to (i.e. when you get redness and other symptoms from the flu shot). Viruses that are grown in chicken fibroblast cells (not in the egg, just in cells) do not experience an allergic reaction because the virus was never in the whole egg. So even though the measles vaccine is grown in chicken fibroblast cells, there is no reported evidence of having an egg allergy to this. Another concern is the use of chicken embryos in general. Often when people hear the word embryo, they do not realize that we mean a chicken egg. So if you don’t have an issue with eating chicken or egg products, there should also be no issue with this process. However, some people are ethically against the use and/or consumption of animals, period, and thus this is a legit concern to have. Unfortunately, we don’t have a better way to mass produce the amount of virus needed for vaccines and other research purposes. Some researchers are currently working on genetically engineering attenuated viruses and others are working on alternatives to animal testing. But these standard practices are currently the most reliable tools we have.

Common concern: Use of human fetal diploid cell lines to passage virus Let’s get some definitions out of the way. You may see the term ‘human diploid cells’. Diploid refers to the number of copies of chromosomes found in a cell (di = two). If you remember from science class, most cells of the body, besides your sex cells, are diploid. So nothing out of the ordinary there. Second, I’ve observed online that some people are confused about the term “cell line.” A cell line is a cell culture developed from a single cell and therefore consisting of cells with more or less identical genetic makeup. You can propagate some cell lines indefinitely. This is important to understand because we can isolate cells from a tissue once and then culture them for decades–we don’t isolate cells from new tissues over and over again. There are two cell lines that were first created in the 1960’s that are used to make some vaccine viruses and were originally derived from two human fetuses called Wi-38 and MRC-5. Both the Wi-38 and MRC-5 cell lines are composed of fibroblast cells from lung tissue. I’ve observed some confusion online regarding the synthesis of these cell lines: some people think fetuses are sacrificed every time this cell line is used. It’s important to understand that this cell line was made in the 1960’s from two fetuses that were already destined for abortion. The parents agreed to donate the fetuses for research at the time of termination. Others are concerned about the religious implications of using fetus cells in vaccines. First, some people are under the impression that you can find fetus cells in the final vaccine product. This is not true: the virus is isolated from the cells and washed several times. Second, the Vatican has issued a statement several years ago that is it acceptable to use vaccines that were prepared with these cells as it serves for the greater good. They also ask for better methods of vaccine manufacturing that will avoid using these cell lines. Asking for better methods is definitely a great suggestion, just remember that you need to support science funding in order for that to happen! Please read this article for more information about the cell lines used and the religious implications.

Common concern: vaccines contain cells (whether they be human, animal, other)
Please note that viruses are removed and purified from cells before vaccine manufacturing. You will see on some package inserts that residual amounts of cellular products MAY be found in the final product. I am personally not concerned about this after reading Plotkin’s article here and knowing that we consume plant and animal cells at a much larger rate than the miniscule amount found in vaccines. The vaccine product is also extensively tested and scanned for any dangerous contaminants before release.

If you read the previous articles, I hope you can see that production of the vaccine virus is separate from production of the final vaccine product that is injected into you. This means that the ingredients we have discussed so far, including animal and human cell lines, are not found in the final product (except possibly in amounts less than 1 ppm).  In the next article, we will get into how the vaccine virus is packaged into the vaccine product and what ingredients are actually found in the injectable form.

Photo credits:
Figure 1. Virus Attenuation. Taken from: http://www.nature.com/nm/journal/v14/n2/full/nm1726.html
“Attenuation of measles strain” diagram modified from Plotkin et al. “Vaccines.” (textbook). Philadelphia: Saunders; 2012.

Sources:
Plotkin et al. “Vaccines.” (textbook). Philadelphia: Saunders; 2012.
Plotkin. “The history of Rubella and Rubella vaccination leading to elimination.” Clin Infect Dis. (2006) 43 (Supplement 3): S164-S168.
Hilleman et al. “Live, Attenuated Rubella-Virus Vaccine.” N Engl J Med 1968; 279:300-303

Please let me know if you spot any inaccuracies in this text at PHUpodcast@gmail.com

Santa Claus Is Not Real!? How Talking In Absolute Truths Damages Public Trust

“There is no absolute knowledge. And those who claim it, whether they are scientists or dogmatists, open the door to tragedy.”   ― Jacob Bronowski, The Ascent of Man

Science is often portrayed as truth and non-truth. However, science is a construct of humans and is therefore open to error and limits. As famous physicist Bronowski has pointed out, “Science mimics nature, science is not nature itself.” This makes it difficult to conclude anything with 100% certainty. Sometimes I get discouraged in the lab since experiments seem so far removed from what is actually happening in the body; how can you conclude anything? My immunology professor, Al Scott, told me that we can gleam multitudes of information from simplified models, but we must be aware of the inherent limitations. Cautious optimism, that’s what he called it.

There are certain experiments, however, that have been tested many times with the same outcome, where the uncertainty becomes minimal. Take the relationship between cancer and smoking. There have been thousands of studies showing that there is an association between smoking and cancer (read: if you smoke, you are at higher risk for cancer). Notice the wording here, scientists do not say, “If you smoke, you definitely will get cancer.” We can’t actually state this with 100% confidence.

As results trickle down to medical professionals and the public, the association becomes absolute truth: cigarettes are labeled as carcinogens. Doctors make recommendations. Patients trust their doctors. Imagine that a study involving 10 mice comes out, showing most mice in this study did not develop cancer after “smoking cigarettes.” While the scientific community dismisses this data after reading the journal article (the dosage was extremely low, the time course was short), CNN and Fox News run a story saying, “Smoking Does Not Cause Cancer.” The public becomes upset and possibly enraged; they feel betrayed by the public health community. Mistrust grows and the public turns to online sources for their medical information. People believe they know more than their doctors and refuse medical advice.

The public has found out Santa Claus is not real. How can they trust anything we say?

This vicious cycle is common. And it is certainly true of the current ‘debate’ on vaccines and autism. It was just one guy, ex-doc Andrew Wakefield, who published falsified data that spurred on a huge public uproar. It continues to whittle away the trust between public health professionals and the public.

Everyone gets frustrated. The scientists are frustrated at the public’s lack of understanding of scientific principles that seem logical to them. Doctors are frustrated because patients don’t trust in their interventions, and worse, are putting themselves and the population at greater risk for preventable diseases. The public is frustrated because they are scared and feel out of control of their health choices; no one knows who to trust so they resort to, for example, Wikipedia because that’s the only understandable resource available. It’s also frustrating because there are lots of people out there who want to make educated choices, but most likely their last biology class was years ago. Even if remembered, it wouldn’t help to understand the complexity of vaccine science.

It’s easy to blame other domains for this predicament, i.e. our education system sucks, people are stupid, doctors don’t have enough time, scientists don’t have the training… But we must all take responsibility for better science communication. I for one pledge to practice daily how to describe complex science ideas and I will start by writing another Public Health 101 article. I keep putting this off because it’s tough, but it’s so important. What small daily goal can you think of to improve your science communication and understanding?