Purity, impurity, infectious diseases

The cover story of the December issue of the International Journal of Environmental Research and Public Health is devoted to a girl, Jennifer Worrall, and Jasmin, her beloved rat.  “In 2012 in the United Kingdom, a number of people caught Seoul hantavirus from their pet rats –  explains the editor - Pet rat owners were warned about the potential risk their pets posed; however, they did not want to change the way they interacted with them. To understand why, we interviewed pet rat owners to explore how they made sense of the disease and the risk it posed.”

The paper - authored by a multidisciplinary team, including veterinary and public health doctors, and psychologists, at Liverpool University – reports a study based on seven in-depth interviews with pet rat owners and breeders in England. The goal was “to elicit an understanding of disease and risk in human populations in contact with pet and wild rats.”   Researchers identified four themes “relevant to the design of public health messages.” They called the first theme “A Tale of Two Rats,” according to this theme pet and wild rats are no longer perceived as the same species by rat owners. Of course, rat owners do not context biological classifications, and they are rationally aware that pet and wild rats are the same animal, yet, emotionally and practically speaking, they consider pet rats as though they were an autonomous species.  The second theme is the “hierarchy of purity”. Researcher discovered that pet rat owners create their own hierarchy of purity among rats, being wild rats at one extreme (impurity) and their own pet at the other extreme (purity), in between all other rats, ranging from rescued rats (e.g., saved from labs) to pet shop rats. The most a rat is perceived “pure,” the less the animal is object of hygienic and preventative measure, irrespective of any public health authority recommendation. The third theme is “bounded purity.” Purity and impurity appear to be strictly bounded to home borders. Events affecting pet rats, originated in, and happening inside of, the home do not threaten their purity, while purity is threatened by any event occurring outside of the home, and affecting pets. Impurity is associated to out-of-place situations.  The fourth theme is “The Divergent Worlds of Pet Rat Owners and Health Officials.” It concerns the two different models of diseases shared respectively by pet rat owners and health officials. While the latter see the world through the lens of the standard medico-scientific model of infectious disease, the former perceive their own world as a separate space, where standard rules do not apply.  Each pet rat owner believes his own case to be an exception, that cannot be captured by the standard medical model. 

Why – researchers ask themselves and the reader – were these four themes so successful in preventing an effective response to the actual threat to human health posed by Seoul virus? Because – they answer – the biomedical model of disease was problematic for this virus, which can infect rats and human without causing any symptom of infection and disease, e.g. according to Public Health England “one third of pet rat owners tested were seropositive to the virus; however, not these individuals actually experienced the disease by becoming ill.”   Authors conclude “Seoul virus (…) is ambiguous, composite, in-between (…) it is an anomaly. Rather than responding negatively to this anomaly, by ignoring the risk it poses, owners have responded more positively by creating a new reality in which Seoul virus has a place: a ‘hierarchy of purity’”. There are several reasons of interest in this paper. Two of them are worth mentioning, they both regard “purity.”  

The first reason of interest concerns the lesson for public health communication. The couple purity /impurity is in the limelight of contemporary scholarly studies on public perception  of infectious diseases and the origin of  vaccination hesitancy.  Scholarly speaking, considerations on purity and impurity should play a pivotal role in health communication. Unfortunately, professional communicators often lack the necessary scholarship, historical depth, and perspective. So, they fail to grasp crucial cultural nuances. The very notion of contagion – that today we take for granted belonging to the medico-scientific register –  originates from the couple purity /impurity and it is as ancient as human civilization itself. Assuming that less than two centuries of germ theory have modified the collective mindset, is naïve and misleading. Conceptions about purity and impurity return repeatedly, only a bit masked by pseudoscientific languages, and they still rule public perception of communicable diseases.   

The second reason of interest concerns a common misunderstanding. Most scholars, who have recently discussed the issue purity/impurity in relation to infectious diseases and vaccination, have labelled it as a “moral” issue. This is a methodological mistake, which prevents understanding many nuances of the couple purity/impurity, which originates from deep, collective, fantasies, much wider than ethics.  Actually the opposition between purity and impurity provides a valuable interpretative framework for a range of social phenomena, including  attitudes towards GMO foods, xenophobia, and policy preferences.  The Liverpool team deserves the full credit for avoiding such a mistake as well as the easy solution to turn “everything into ethics.”  

When research is aware of complexity and properly done, one could learn a lot even from a young lady and her pet rat, which is, maybe, the most important lesson taught by this paper.

Avian Flu Diary: Smithsonian `Next Pandemic' Webinar Now Available Online

Avian Flu Diary: Smithsonian `Next Pandemic' Webinar Now Available Online

The Dengvaxia affair

In 2016 the Philippines started a vaccination campaign against Dengue, a mosquito-borne tropical disease, infecting worldwide hundreds of millions people,  whose seriousness is however usually limited, “Dengue fever is a severe, flu-like illness that affects infants, young children and adults, but seldom causes death”. The Philippines’ immunization programme was based on Dengvaxia, a vaccine produced by Sanofi Pasteur, which was known to provide an effective prevention in subjects who had prior infection. Since early 2016, however, Scott Halstead, the leading scientist in dengue research, had denounced that Dengvaxia could cause a phenomenon that he first described in 1977  calling it ADE, or antibody-dependent enhancement.  ADE, which implies that antibodies increase viral infectivity and consequently severity of an infection, is not rare in lab cell cultures, but it has been rarely demonstrated in vivo, although it has been suspected in some cases. In March 2016, Halstead and Russel published a short paper whose conclusion read “hospitalized cases among vaccinated seropositives (…) were greatly reduced by vaccination. But, seronegative individuals of all ages after being vaccinated were (…) at increased risk of developing hospitalized disease during a subsequent wild type DENV infection”.  Sanofi Pasteur contested this  conclusion, arguing that  it was not enough supported by data.  Halstead went on warning Sanofi and  the WHO to be cautious before launching any mass vaccination campaign. " We have a vaccine that enhances dengue"  he declared  in a 2016 interview “It's clear as the nose on my face: Vaccine recipients less than 5 years old had five to seven times more rates of hospitalizations for severe dengue virus than placebo controls”. In response, the World Health Organization convened a Strategic Advisory Group of Experts (SAGE) who reviewed the evidence. SAGE’s conclusions, published on July 2016, recommended that “countries should consider introduction of the dengue vaccine CYD-TDV only in geographic settings (national or subnational) where epidemiological data indicate a high burden of disease (…) seroprevalence, should be approximately 70% or greater in the age group targeted for vaccination in order to maximize public health impact and cost-effectiveness. Vaccination of populations with seroprevalence between 50% and 70% is acceptable (…) the vaccine is not recommended when seroprevalence is below 50%”.  These conclusions were puzzling  because they were based on the concept that an immunization campaign – addressing  a serious disease, however, rarely deadly – could be legitimate even if  public health authorities suspect that a percentage of vaccinated subjects not only will not benefit from vaccination, but they will be exposed to increased risks.  WHO position paper gave in fact the green light for the Philippines vaccination campaign. Now - on November 29, 2017 - Sanofi Pasteur released a new statement, admitting that-  after analysing data from a six-year study -  Halstead was not probably so wrong because  “the analysis found that in the longer term, more cases of severe disease could occur following vaccination”.  This is particularly worrisome in the case of children vaccination, given that a child is less likely to have had a previous dengue infection. A few days after Sanofi’s release, the Philippines department of health took the decision – soon corroborated by of the World Health Organization  - to suspend the Dengue vaccination programme. Probably a bit too late, however, given that some 830,000 children in the Philippines, and around 300,000 in Brazil, where an analogous programme was running, were already vaccinated. We don’t know how many of them were seronegative, and consequently it is  impossible to predict the impact that Dengvaxia could have on them.

From a risk communication perspective this story incites to make two points and a final reflection.

The first point concerns the “storyline”. Once again, the public is faced with a plot made of a honest scientist, whose alerts are overlooked by public authorities and institutions, and a villain played by pharma industry. Can it be possible that we are still repeating this plot for the umpteenth time? Why people don’t learn the lesson? How could one hope that public authorities, health institutions, the WHO, pharma industry, are trusted if they are so stupid to start an immunization campaign -  addressing a non-mortal disease (at least in most cases), and involving children - when there are concrete risks to be obliged to discontinue it very soon? Both Sanofi Pasteur and the WHO were indeed aware since July 2016 that Halstead was likely to be right, otherwise WHO Position Paper of July 2016 would not make any sense. Could they realistically imagine that political authorities could put up with an immunisation campaign threatening to increase risks in a category – be it large or small – to which each citizen could fear to belong, if she does not take a blood test?

The second point concerns “money”. It has been told again and again that pharma companies do not make money with vaccines,  this is one of the tritest arguments used to challenge conspiracy theory on vaccination. It is probably time to say that this argument is misleading. The global economy is hardly the traditional market economy, and money is not made – if not marginally – by selling items. In a financialized economy, one should  look at the financial market to understand what is going on. In the last five two years, Sanofi share increased its value from a lower bound at 67 Euro in 2016, to around 83 Euro in May 2017. After the Dengvaxia affair, Sanofi share is losing about 0,8 %.  Repeating the tale that industry does not gain money with vaccines is offensive to people’s intelligence, and once again it is a stupid move in communication terms.

The final reflection concerns anti-vaccination movements. In principle, the Dengvaxia affair could have been written by them, it seems the almost perfect case to be used to attack vaccines and vaccination, yet anti-vaccination activists are surprisingly absent, at least till today. Google trends shows that impressions concerning this affair are largely concentrated in the Philippines, and, much less, in a few other Asian countries and in Brazil. Industrialized countries, where anti vaccination movements are mostly active, don’t show to be interested in Dengvaxia. The U.S. as well as E.U. countries show a rate of impressions lower than 1% than the Philippines. Even France appears to be not interested, notwithstanding Sanofi is French and France is the country hosting the world largest group of people hesitant to vaccination. This is confirmed by  social conversation. The Dengvaxia affair is having a very low social penetration, geographically concentrated in the Philippines and a few other countries. Maybe this scenario will change in the next weeks, hopefully not, but for now it is difficult to escape the sensation that anti vaccination activists are hardly interested in people's health. This seems to confirm once again that anti vaccination is a symbolic war, which mostly concerns  fantasies on purity and impurity, collective dreams and, unfortunately, also nightmares, but has little to do with facts.

CULTURE AND MICROBIOLOGICAL CULTURES

Let me welcome the November issue of Microbiology Today, the quarterly magazine of the Microbiology Society, which is devoted to ‘Microbiology in Popular Culture’.

The magazine hosts five pleasant articles and a commentary from the editorial team.  Articles range from the interesting and helpful Genome editing and the cultural imagination, which discusses the importance of the choice of words in science popularization reporting the main findings of a recent project carried out by Genetic Alliance UK and the Progress Educational Trust (Basic Understanding of Genome Editing), to Killer microbes in movies, a piece that – as promised by the title - deals with killer microbe doomsday scenarios in movies. Even lighter articles as this one, offer interesting points, which would deserve to be further elaborated. For instance, Andrew M. Burns and David Bhella ask themselves and to the reader why viruses are preferred to bacteria to play the villain role in “films based on mass deaths from infectious disease”. Their answer is thought provoking, because – they argue – virus are simpler. E.A.Poe, who created one of his most fascinating short stories, The Purloined Letter, around the idea of simplicity, and always praised simplicity, would have not provided a different answer; to human nothing is as beautiful and disturbing as simplicity. Other articles deal with forensic microbiology in popular culture, Managing the myths – the CSI effect in forensic science, with fungal diseases and video games, Not such a fungi – fungal disease and the end of the world as we know it?, with spatial exploration and germs, Terra Firma II: terraforming Earth’s sequel. Overall, the magazine is quite enjoyable and educational, notably for those who are involved in microbiology and communication. “Popular culture – notes Amy Chambers in her final comment - can subtly and powerfully communicate ideas and stories about science in ways that other methods cannot. A science-based movie is more likely to inspire rather than (re)educate someone about science”.

Microbiology Today should be read in parallel with another pleasant piece, published on Nov 30 by Forbes and authored by Kavin Senapathy. The article is devoted to “The 5 Most Laughable Non-GMO Project Verified Products”. Kavin entertainingly describes some of the oddest products advertised as GMO free in the U.S. market. They include a brand of cat litter, a marque of “organic” vodka, various homeopathic medications and even HimalaSalt – “the purest salt on earth created 250 million years ago during a time of pristine environmental integrity”. If it is difficult to imagine how salt could be ever genetically modified, and it is also comical to see that homeopathic products, whose ingredients are undetectable, can be promoted as GMO free, yet the funniest case is definitely the cat litter producer, which proudly declares in its website “our litter is made out of 100% U.S. sourced grass, certified biodegradable, no chemicals, fragrances, perfumes or clay, non GMO project verified”. 

Why is it instructive reading this article in parallel with the issue of Microbiology Today? Because comparing the two, it becomes at once clear how science education and communication are hardly a matter of “passing down” information, and they are instead a complex and nuanced exercise of human communication, in which emotions, imagination, desires and fears, are often more important than evidence and data. Dr House, who politely explains to a mother why she should vaccinate her child, is worth hundreds scientific conferences, not to mention many public health campaigns.

In his introduction to the Microbiology Today issue, Neil Gow, president of the Microbiology Society, jokes with the twofold sense of the word “culture”, human culture and microbiological culture(s). He is righter than he probably imagines. “Culture” comes from Latin “cultura, which originally meant agriculture and then, metaphorically, also education, care, and so. Fascinatingly enough, the Latin word cultura was the future participle of the verb còlere, to farm, to cultivate. Culture is thus our future,  it is -so to speak – the fruit of our land, and “by their fruit you will recognize them”(Matthew 7:16)

(from http://riskcommunication.rtexpert.com/#/)