Several years ago a friend asked me to look at the possibly efficacy of the herbal supplement Protandim and whether the claims of the marketers were scientifically justified. This page discusses the results of my research.


The pandemic of SARS Cov-2 infections in early 2020 created a number of controversies regarding appropriate responses. As a biomedical researcher I was very interested in how governmental policy responses were or were not related to the underlying scientific research. Consequently I have done a fair amount of reading of the evolving literature on this pandemic and statistical analyses of the associated datasets. The following describe a number of those:


  • Graph of the number of positive tests for SARS Cov-2 in the state of Arizona as a function of calendar date.
  • Graph of the an estimate of the effective reproduction number of positive cases as a function of calendar date for each state. Horizontal dashed grey line shows 1 where the rate of case growth is stable.
  • Graph of the fraction of positive tests in the state of Arizona.
  • Graph of the number of new cases of Covid-19 versus the number of tests performed in the state of Arizona.
  • Graph of the number of patients hospitalized at one time versus the number of tests performed in the state of Arizona.

Cloth mask wearing by the general public

The DANMASK-19 study (Bundgaard et al. 2020) was a large randomized study in Denmark on the effect of the general public wearing surgical masks. The results of this study have been subject to much politicized interpretation because it failed to find a statistically significant result using conventional significance levels. This page describes in detail the statistical interpretation of this study. In brief summary, the DANMASK-19 study failed to find a significant effect (p<0.05) of wearing surgical masks on the likelihood of being infected by Covid-19 amongst the general public. A 95% confidence interval for the magnitude of any change in the rate of infection ranged from a decrease of 46% to a 23% increase. The most likely change in rate of infection was a 15% decrease though there was also a 25% chance that wearing a surgical mask increased the rate of infection.

In late 2020 and early 2021, there were 2 newer peer-reviewed reviews of the scientific literature on whether the general public wearing cloth masks will slow the spread of Covid-19. Overall they suggest that while it seems like mask wearing should work, it does not do so when actually tested in practice using randomized controlled studies.

  • Jefferson et al. is a systematic review of the randomized controlled studies which states that there is moderate certainty evidence that wearing medical/surgical masks probably makes little to no difference to laboratory confirmed influenza. (This review did not consider the Bundgaard et al. study as it was not published yet.)
  • Howard et al. which recommends mask wearing based on a combination of laboratory, observational, and older reviews of the randomized controlled studies.

A commentary by Jefferson and Heneghan which notes that the recommendations in July 2020 for the general public to wear masks appeared to be based on politics rather than good medical practice.

A commentary by Mahase discusses the advantages and problems with the general public wearing cloth masks and includes other expert discussion.

The Alleged Link Between the MMR Vaccine and Autism

In 1998, Andrew Wakefield and collegues published a paper in the Lancet alleging a link between the administration of the MMR vaccine and autism. The paper was subsequently retracted because it contained 5 scientific frauds in the paper itself and one in Wakefield's response.

My article on these frauds was published in the November/December 2020 issue of the Skeptical Inquirer.

Transcripts of the Medical Research Council hearing on this issue, which resulted in Wakefield's medical license being revoked, are available here.