{'fraction_non_alphanumeric': 0.022988505747126436, 'fraction_numerical': 0.0019157088122605363, 'mean_word_length': 5.301204819277109, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Influenza vaccination: policy versus evidence

Jefferson believes that his systematic reviews show that influenza vaccines “have little or no effect on the effects measured.”1 He wonders why there is a gap between evidence and policy. 

Jefferson identifies three reasons why his evidence contradicts policy. 

Firstly, policy relies heavily on non-randomised studies. Yet his preference for randomised controlled trials is based on historical, pragmatic, and heuristic reasons and cannot be justified on epistemological …