Effectiveness of influenza and COVID-19 vaccines
Dr. Cunningham argues that the results in Anderson et al. (2020) "do not preclude the possibility that influenza vaccines have significantly increased mortality in the elderly," pointing to a single cherry-picked, statistically-insignificant result. This line of argument echoes US Secretary of Defense Donald Rumsfeld's principal argument leading up to the 2003 Iraq War: "Absence of evidence [of WMDs] is not evidence of absence." Spoiler alert: There were no meaningful stockpiles of WMDs in Iraq.
The influenza vaccine has proved to be safe and efficacious at reducing the incidence of influenza in dozens of randomized controlled trials, the gold standard of empirical evidence. Nothing in our study, or Dr. Cunningham's anecdotes, changes that core conclusion.
Apropos of the original BMJ article, there are now three approved COVID-19 vaccines in the US, and an equal number in the UK. These vaccines have proved safe and efficacious in large-scale clinical trials. The J&J vaccine, which received Emergency Use Authorization last week, achieved an estimated 80% effectiveness against all-cause mortality in its trial (95% CI, 30% to 100%) . Its true effectiveness against all-cause mortality, after accounting for plausible statistical noise, almost surely exceeded 30%.
This is likely the first time in history in which a treatment has plausibly achieved >30% effectiveness against all-cause mortality when tested in a large-scale clinical trial drawn from the general population. It is the result of deploying a highly effective vaccine against a disease that features a historic combination of communicability and lethality. Everyone who has the opportunity to receive an approved COVID-19 vaccine should absolutely do so. I received my first dose of one last week.
Michael L. Anderson, PhD
 "COVID-19 Vaccine Ad26.COV2.S VAC31518 (JNJ-78436735) Sponsor Briefing Document" https://www.fda.gov/media/146219/download
Competing interests: No competing interests