In the early 20th century, the world was plunged into a state of frenzy. Poliomyelitis, or polio for short, was a formerly sporadic disease caused by poliovirus that had grown to become a global pandemic. At its height, 22000 people in the US alone were left paralysed each year, their motor neurons destroyed (Trevelyan, Smallman-Raynor and Cliff, 2005; Harris and Coyne, in press). By the early 1950s, the “wrath of God”, as the disease had come to be known, was creating widespread panic. Understandably, both the public and health authorities collectively let out a sigh of relief when Jonas Salk discovered the first polio vaccine in 1953.
Despite having been tested initially on only 161 human subjects, Salk’s vaccine, which he called Inactivated Poliovirus Vaccine (IPV) quickly became available on the market (Salk, et al., 1953). Salk’s protocol for producing IPV involved incubating poliovirus in formaldehyde, effectively killing the virus while leaving the viral coat proteins intact. When injected into patients during vaccination, the polio proteins triggered antibody production against the viral proteins (Khan, 2009). Since IPV involved dead pathogens, antibodies were not continually produced and IPV therefore needed to be frequently administered to confer long-term immunity (Khan, 2009). In spite of this downfall, within a year of IPV’s introduction, polio cases in the US dropped from nearly 58000 to just 5600 (Mehndiratta, Mehndiratta and Pande, 2014). Yet victory was to be short-lived. Shortly after laboratories in the US began production of IPV, it was discovered that the batch of vaccine produced by Cutter Laboratories actually resulted in 40000 new cases of polio. Investigations revealed that during IPV production, small populations of the virus had evaded inactivation, and had actually been administered as live virus to patients (Fitzpatrick, 2006). This horrific event came to be known as the Cutter Incident.
Public opinion of IPV quickly declined after the Cutter Incident, leading to the development of an Oral Poliovirus Vaccine (OPV) by Albert Sabin in 1961. Instead of killing the virus, Sabin’s vaccine involved weakening or attenuating the virus by growing it in a foreign host such as monkey kidney epithelial cells (Khan, 2009). This caused adaptations favourable to its survival in the foreign host, but unfavourable to its survival in humans. When injected into a human patient as OPV, the virus grew slowly because it was not adapted to the normal host. OPV was successful in that it mimicked a natural infection and thus triggered both T-cell and antibody responses, requiring only one administration of the vaccine (Khan, 2009). However, health authorities quickly realized that the weakened virus could revert back to its original virulent form, infecting previously vaccinated patients and spreading to other individuals via the fecal-oral route (Modlin and Wenger, 2014). It was realized that OPV therefore was not as effective as previously thought, especially in developing countries with poor hygiene where polio was rampant.
Perhaps because of the downfalls associated with each vaccine, the ensuing decades saw both IPV and OPV undergo tremendous modifications to improve vaccine potency. Today, thanks to Salk and Sabin, combinations of IPV and OPV are used to vaccinate newborns and polio no longer poses a serious health threat to mankind (Faden, 2014). In the span of half a century, vaccines have pushed the polio pandemic to the brink of eradication. Despite this success story, anti-vaccine movements live on. One can only hope that as the public becomes more aware of the power of vaccines, vaccine compliance will improve so that history will not repeat itself.
Works Cited
Faden, H., 2014. Poliovirus vaccination : a trilogy. The Journal of Infectious Diseases, 168(1), pp.25–28.
Fitzpatrick, M., 2006. Commentary on “The cutter incident: how America’s first polio vaccine led to a growing vaccine crisis”. Journal of the Royal Society of Medicine, 99, p.156.
Harris, K.G. and Coyne, C.B., in press. Death waits for no man – does it wait for a virus? How enteroviruses induce and control cell death. Cytokine & growth factor reviews.
Khan, F.H., 2009. The elements of immunology. New Delhi: Pearson Education.
Mehndiratta, M.M., Mehndiratta, P. and Pande, R., 2014. Poliomyelitis: historical facts, epidemiology, and current challenges in eradication. The Neurohospitalist, 4(4), pp.223–9.
Modlin, J. and Wenger, J., 2014. Achieving and maintaining polio eradication – new strategies. The New England journal of medicine, 371(16), pp.1476–9.
Salk, J.E., Bennett, B.L., Lewis, L.J., Ward, E.N. and Younger, J.S., 1953. Studies in human subjects on active immunization against poliomyelitis. JAMA, 151(13), pp.1081–98.
Trevelyan, B., Smallman-Raynor, M. and Cliff, A.D., 2005. The spatial dynamics of poliomyelitis in the United States: from epidemic emergence to vaccine-induced retreat, 1910–1971. Annals of the Association of American Geographers, 95(2), pp.269–293.
Comments
9 Responses to “Combating the Crippler”
Hi everyone,
This post is about the trials and tribulations the scientific world faced when developing a vaccine for polio. The post was inspired by a Google doodle celebrating Jonas Salk’s 100th birthday a few weeks ago, so I thought I’d dedicate a post to him. I did some reading into Salk’s vaccine and found the immunology behind vaccines to be pretty cool. I also thought the history behind the vaccine development was very interesting (I mean, who tests their vaccine on only 161 people before they market it?!).
Any and all feedback welcome. Enjoy!
Alan
Hey Alan,
Great job on your blog post!
A few suggestions would be the first paragraph is a little choppy. I think you did a great job of including lots of information and setting the stage, but there are a lot of commas specifically toward the beginning of the sentences. It may also be interesting to make it clear that this virus can infect the water supply whereas ebola is transferred person to person, to help the reader understand the differences between the epidemics.
Thanks,
Katie
Hi Katie,
I agree I that I do have many commas, but I feel that in this case it helps with the flow and doesn’t detract from the writing as much. Thanks for pointing that out!
In regards to differentiating between the modes of transmission of ebola and polio: I only mentioned ebola to end my post in an effective way, as I felt it would help the reader relate to some of the current events that are going on. For this reason, I did not want to delve into a discussion about polio VS ebola. Thank you for pointing this out though, as it means I might have to find a better way of ending the post without making people think that I’m talking about another topic.
Alan
Hi ALAN!
This was well-written and I took on a unique historical perspective. I really enjoyed how you laid out the article and thought it was really well done. There is not much to change. One thing I would suggest would maybe be to include an image. Some people might not know how viruses and immunology may work. An image might help people to visualize this. I also think it might be useful to mention the Ebola problem initially in the introduction. It can be used in your introduction to add relevance to why you selected this topic or why you started looking into historical vaccines. I think it was a little late to mention Ebola in the last sentence. Other than that, this was impeccable!
PS COOL TITLE!
Happy Editing,
Vincent
Hey Vincent,
Yea, I mainly mentioned Ebola to give the reader an interesting thing to think about: if we were able to (almost) eradicate polio, could we do the same for Ebola? For this reason, I did not know how I could integrate Ebola into the introduction. I also feel that as my post is geared more toward the development of vaccines, it might be awkward to talk about Ebola in the first paragraph. Thank you for your comment though. I might have to end off my post in a different way.
Alan
Hi Allan,
I think you post is quite good as is, but have a couple comments to make. First, I would introduce Cutter laboratories before (rightfully) bashing them for infecting so many people. This would add some context. Second, in your explanation of OPV you wrote that the virus was weakened by growing it in a foreign host. Then you go on to say that the virus evolves to become stronger in the foreign host. This section could by clarified by something like: ‘ The virus was grown in a foreign host. This caused adaptations favourable to its survival in the foreign host, but unfavourable to its survival in humans.’ Finally, I’m not clear on how the virus would revert back to its original form and infect someone who was previously vaccinated. I understand the fecal oral route for unvaccinated people, but you mentioned that the OPV only required one vaccination. Is the original form of the virus significantly different, such that the OPV vaccinated patient is still somewhat susceptible to the original form?
Rui
Hi Rui,
Thanks so much for your comments. I found it difficult to introduce Cutter Laboratories before I bash them, so instead I clarified the beginning of that sentence to mention that several laboratories were producing IPV when it was discovered that Cutter Laboratories production was subpar. I have also taken your suggestion for the sentence about OPV being grown in a foreign host. I hadn’t realized that it was confusing beforehand, so thanks for pointing that out.
In regards to your last comment, yes, the original virus is virulent (I have added this specification). If the weakened virus reverted back to its virulent form, the person that was vaccinated would essentially have the virulent virus and would be infected with polio.
Alan
Hey Alan,
I really enjoyed the approach you took to this topic. Your introduction was especially effective, and you did a great job of maintaining interest throughout your post, without getting bogged down in details. A few comments for you:
– I’m questioning your choice to use “global epidemic” over “pandemic”. If you’ve got a reasonable justification for it then I’ve got no problem with it, I’m just wondering what that justification is.
– There’s a split infinitive in the first sentence of your second paragraph (“having been initially tested”). It’s not the sort of thing I’ll nitpick while grading, just thought I’d point it out for future reference.
– This phrase: “viruses best adapted to survive in these abnormal conditions were selected for” could be worded a little more clearly. While its meaning is obvious to anyone who’s done work in evolutionary bio, I can’t imagine that it would be easy to parse for the uninitiated.
– You’ve finished off on a reference to the current Ebola crisis, which is interesting, but considering the specific nature of your topic (vaccines, rather than pandemics in general), a connection to vaccine compliance in the wake of Jenna McCarthy and her cronies might be a bit more topical.
Overall, the tone and structure of your piece were very effective. Happy writing!
Julie-Anne
Hi Julie-Anne,
Thank you for your comments. I have fixed the split infinitive, looked into pandemic vs epidemic (it seems pandemic is the more correct term), and attempted to clarify that phrase about weakened viruses not being adapted to human hosts. In addition, based on the comments I’ve received, it seems my reference to Ebola is not the clearest. I’ve followed your suggestion and have tried to end my post with a connection to the anti-vaccine movement and vaccine compliance. Hopefully this clears up the confusion, and is just as effective as a conclusion.
Alan