TV report on DTP galvanizes US pediatricians

How do Twitter users react to TV broadcasts dedicated to vaccines in Italy?

BACKGROUND

Social media monitoring during TV broadcasts dedicated to vaccines can provide information on vaccine confidence. We analyzed the sentiment of tweets published in reaction to two TV broadcasts in Italy dedicated to vaccines, one based on scientific evidence [Presadiretta (PD)] and one including anti-vaccine personalities [Virus (VS)].

METHODS

Tweets about vaccines published in an 8-day period centred on each of the two TV broadcasts were classified by sentiment. Differences in tweets' and users' characteristics between the two broadcasts were tested through Poisson, quasi-Poisson or logistic univariate regression. We investigated the association between users' characteristics and sentiment through univariate quasi-binomial logistic regression.

RESULTS

We downloaded 12 180 tweets pertinent to vaccines, published by 5447 users; 276 users tweeted during both broadcasts. Sentiment was positive in 50.4% of tweets, negative in 37.7% and neutral in 10.1% (remaining tweets were unclear or questions). The positive/negative ratio was higher for VS compared to PD (6.96 vs. 4.24, P<0.001). Positive sentiment was associated to the user's number of followers (OR 1.68, P<0.001), friends (OR 1.83, P<0.001) and published tweets (OR 1.46, P<0.001) and to being a recurrent user (OR 3.26, P<0.001).

CONCLUSIONS

Twitter users were highly reactive to TV broadcasts dedicated to vaccines. Sentiment was mainly positive, especially among very active users. Displaying anti-vaccine positions on TV elicited a positive sentiment on Twitter. Listening to social media during TV shows dedicated to vaccines can provide a diverse set of data that can be exploited by public health institutions to inform tailored vaccine communication initiatives.

The pertussis vaccine controversy in Great Britain, 1974-1986

This historical essay analyzes the role played by Great Britain in the pertussis vaccine controversy of the 1970s and 1980s. Public backlash against this vaccine not only took place earlier in Britain than the United States, but also was so widespread that a series of whooping cough epidemics soon followed. As with the more recent dispute involving measles-mumps-rubella (MMR) vaccine and autism, the United Kingdom played a primary role in defining, promoting, and ultimately exporting this controversy. This essay seeks to explain this phenomenon by situating it in Britain's long history of suspicion regarding vaccines evident among both the public and the medical profession, a theme dating back to the compulsory vaccination laws of the 19th century. It argues that anti-vaccinationism, far from being simply a new development related to the public's lack of awareness of childhood vaccine-preventable illness, actually represents a revival of a much older movement.

An attempt to swindle nature: press anti-immunisation reportage 1993-1997

There is some evidence that low childhood immunisation rates in Australia may be attributed partly to parental antipathy toward immunisation. The anti-immunisation movement is becoming more organised in its efforts to lobby against childhood immunisation, while the lessening of the public's exposure to the effects of vaccine-preventable disease has provided a climate ripe for such a lobby to have a disproportionate influence on parents. Forty months of Australian print media coverage of immunisation were reviewed for anti-immunisation arguments and their underlying ideological subtexts. Of 2440 articles about childhood immunisation, 115 (4.7 per cent) contained statements opposing immunisation. Eight subtexts that referenced wider discourses about medicine, the state and the body dominated anti-immunisation discourse (cover-up; excavation of the facts; unholy alliance for profit; towards totalitarianism; us and them; vaccines as poisonous chemical cocktails; vaccines as cause of idiopathic ills; and back to nature). Attempts to redress claims made against immunisation must not only address specific claims about vaccine efficacy and safety but be grounded in a reframing of the ideological appeals that currently frame the contents of anti-immunisation discourse.

Studies on culture conditions of Bordetella pertussis and relationship to immunogenicity of vaccines

Conditions for growing Bordetella pertussis bacteria in fermentors were studied for the purpose of producing highly protective vaccines. Bacteria with high protective potency were obtained in fermentors when the inoculum consisted of a dense suspension of young B. pertussis cells grown on Bordet-Gengou agar plates. When the time of cultivation in fermentors exceeded 30 h, bacteria harvested showed lower protective potency activity and lower levels of histamine sensitizing factor (HSF) and leukocytosis promoting factor (LPF), indicating that the optimal time for collection is at the end of the logarithmic growth phase. In fermentors, the ATP concentration in the bacterial cells increased from the time of inoculation until the end of the logarithmic growth phase. At the late logarithmic growth phase, the amounts of ATP, HSF, LPF and protective antigen declined rapidly. ATP kinetics thus provides a way of predicting the immunogenicity of vaccines. These results may be applicable to the production of vaccines exhibiting high protective activity at low bacterial concentrations, and to the preparation of soluble vaccines resulting from high-yield extraction of protective antigens. A correlation between the potency and LPF activity of vaccines was established for use in the rapid screening of vaccines for protective activity.

Impaired autonomic responsiveness of the cardiovascular system of the rat induced by a heat-labile component of Bordetella pertussis vaccine

Bordetella pertussis vaccination induces severe impairment of the autonomic responsiveness of the cardiovascular system in rats. The vasodilation after beta 2-adrenoceptor stimulation with salbutamol as well as the negative chronotropic action induced by the muscarinic receptor stimulant arecoline were inhibited 4 days after vaccination. Moreover, basal blood pressure values appeared to be significantly lower in B. pertussis-vaccinated rats compared with control animals. These effects were dependent upon the bacterial strain used. Differences in pharmacological activity due to strain differences paralleled variations in the content of lymphocytosis-promoting factor of the vaccine. The inhibitory effects were absent after the administration of vaccine heated for 1 h at 80 degrees C, implicating an important role for a heat-labile component, e.g., lymphocytosis-promoting factor, and not for a heat-stable constituent, e.g., endotoxin (lipopolysaccharide). Previous studies indicate that some early biological effects elicited by B. pertussis vaccine can be attributed to lipopolysaccharide, whereas late induced effects are mainly brought about by lymphocytosis-promoting factor. For that reason a role for lipopolysaccharide might be excluded because 5 h after vaccination no disturbances of the autonomic nervous system were observed. We conclude that B. pertussis vaccination induces autonomic hyporesponsiveness due to a heat-labile component that is assumed to be lymphocytosis-promoting factor.