There have been more deaths caused by the vaccine than the disease! So should the vaccine programme be cancelled to save lives? To solve that we need to ask the question "What would have happened if we had not run the vaccine programme?". That is a counter-factual question i.e. it is asking us to imagine a different world where we made a key choice differently and to find out what impact that would have had. I will tackle counter-factuals in detail in a future article but for now it is enough to say that the counter-factual makes this a causal inference model that is not well suited to machine learning techniques because it is ab out causation and not correlation.

Dating apps such as Tinder are increasing people's risk of catching a cancer-causing virus passed on through oral sex, dentists warn. Experts say almost half of adults will be infected with the human papilloma virus (HPV) at some point in their life. And while most infections disappear on their own, without even displaying symptoms, some strains can lead to cancer, notably cervical, which in around 90 per cent of cases is caused by HPV. It is also linked to penile, anal, throat, head and neck cancer, as well as genital warts. Hollywood actor Michael Douglas, 72, blamed oral sex for giving him throat cancer in 2010.