A better flu shot for the elderly? High dose flu vaccine as a breakthrough. Or not?
Of course, 24% is relative risk, a meaningless parameter that virtually every newspaper, and so many doctors in academic medicine, use to show an exaggerated effect of medical interventions. What is the absolute improvement with the high dose flu shot? In fact, it is much less impressive. 1.9% of people receiving the standard dose shot developed influenza, while 1.4% of people receiving high dose vaccine developed influenza. That means that 5/1000 fewer people developed flu with high dose vs. standard dose shot, hardly a number worthy of the praise being thrust on high dose vaccination. Also, given how few people developed flu at all, the difference is relatively meaningless and possibly impacted by chance. In addition, fewer people receiving high dose flu vaccine developed serious side effects (8.3% vs 9%, a difference of 7/1000), something that makes no medical sense and also likely the result of chance rather than any meaningful safety improvement with higher dose flu vaccine that should, if anything, cause more adverse reactions. Of course, the press did not comment on any of these realities.
What does all of this mean? First of all, despite the touted 24% risk reduction with high dose vaccine, this translates into a tiny and clinically insignificant absolute improvement with high dose vaccine that may be related to random chance. Second, very few older people developed flu with either vaccination; if there had been a placebo arm of the study, outcome may not have been very much different than either treatment arm. Third, there is no data about the severity of flu in either arm, or if there was a threat to life in those who developed flu. Fourth, both arms had a very high incidence of serious side effects, far higher than any positive impact the shots had on flu prevention. One wonders how effective any flu shot is in preventing medical complications in the elderly compared to its effect in inducing medical complications that are potentially severe. Overall, when this study is evaluated through a lens of common sense, high dose flu shots do not improve meaningful health outcomes in the elderly, can induce serious side effects at an alarmingly high rate, and (in my opinion) should not be used until more data is available. We are quick to leap to conclusions that our medical interventions have a tremendous impact on our patients; the truth is almost always much less impressive when absolute risk/benefit is used, and the complications of the intervention (which is this case were barely mentioned by the press) are almost always more than stated. We have to be very careful about misleading people with such faulty proclamations, or the woman who accused me of threatening the health of an entire community by not using an intervention with no proven efficacy will be pushed to reach conclusions that are both false and potentially dangerous. How can we, as advocates for sensible health care, convince the press that all data on medical interventions should be published using only absolute risk/benefit numbers, and that the risks of interventions must be given as much coverage as the benefits? Sensationalism and erroneous conclusions will not end until this can occur.