MD, PhD, FMedSci, FRSB, FRCP, FRCPEd.

The amount of different so-called alternative medicines (SCAMs) that are being tried or promoted against COVID-19 is legion. Anything really from vitamins to herbal remedies, homeopathics to chiropractic. In fact, it is hard these days to find a SCAM that is not touted for COVID-19.

This study aimed to evaluate if a dietary supplement of quercetin (a polyphenol contained in many fruit and vegetables), vitamin C and bromelain (a proteolytic enzyme contained in pineapple) could be protective against coronavirus infections.

In the verum group, a supplement containing

  • 500mg of quercetin,
  • 500mg of vitamin C,
  • 50mg of  bromelain (QCB)

was administered daily in 2 divided doses for 71 healthcare workers working in areas with high risk of COVID-19, whereas 42 were the control group who received no supplements. The maximum period of follow-up was 120 days. Termination of QCB use prematurely or having a coronavirus infection was the end of a volunteer’s study participation. A rapid diagnostic test was used to detect immunoglobulin positivity.

Graphic demonstrated survival without COVID-19 during follow up time between groups

Graphic demonstrated survival without COVID-19 during follow up time between groups

A total of 113 persons were included. No significant difference were detected between groups at baseline. Mean age of QCB group was 39.0 ± 8.8 years and control group was 32.9 ± 8.7. Average follow-up period for the QCB group was 113 days, and for the control group, 118 days. During the follow-up period, 1 healthcare worker in the QCB group and 9 out in 42 in control group contracted COVID-19. One case was asymptomatic, while others were not. Transmission risk hazard ratio of participants who did not receive QCB was 12.04 (95% Confidence interval= 1.26-115.06, P = 0.031). No significant effect of gender, smoking, antihypertensive medication exposure and having chronic disease on rate of transmission. The authors concluded that this study revealed that QCB was protective for healthcare workers.

The sudy is so poorly written and reported that I had trouble making sense of it. In fact, I first thought it was a fake. Then I saw this note:

Preprints with The Lancet is part of SSRN´s First Look, a place where journals identify content of interest prior to publication. Authors have opted in at submission to The Lancet family of journals to post their preprints on Preprints with The Lancet. The usual SSRN checks and a Lancet-specific check for appropriateness and transparency have been applied. Preprints available here are not Lancet publications or necessarily under review with a Lancet journal. These preprints are early stage research papers that have not been peer-reviewed. The findings should not be used for clinical or public health decision making and should not be presented to a lay audience without highlighting that they are preliminary and have not been peer-reviewed.

If the results are for real (because of the small sample size, the lack of a placebo-control, dozens of potential confounders, etc., the findings could easily false-positive), they would merit urgent replication in a larger, more rigorous trial.

And meanwhile?

Meanwhile I would be very sceptical about the validity of the results. The paper (it really is just a submission for publication in the Lancet; I am not even sure that it will be officially published and I don’t quite see why it is being made available to the public in this way) is too flimsy for words. Despite these warnings, it is likely that many consumers will fall for the claim that QCB was protective for healthcare workers. 

5 Responses to Does a dietary supplement (quercetin, vitamin C, bromelain) reduce the risk of COVID-19 infections?

  • The authors appear to have no grasp whatsoever of mathematics. They report the mean age rather than the median, and give a range without specifying what they mean by that. Then they talk about average follow-up period, average being a non-technical term which is understood differently by different people. When they are talking about hazard ratios they report a confidence interval to five significant figures, a ludicrous and unjustifiable degree of precision. It is quite clear that they don’t understand any of these basic concepts.

    It is also not clear whether the treatment allocation was randomised – since they don’t mention randomisation we have to assume that it wasn’t. The sample sizes were also fairly small.

    The only conclusion that I can draw from this study is that the authors urgently require training in how to conduct medical studies.

    The use of the term average in this context puts me in mind of the BBC quiz show University Challenge (which I always enjoy, though I am no longer quick-witted enough to answer the questions that require rapid calculations). The “average” age of each team is given, which appears to be the mean, alhough that doesn’t really describe the players very well, as an average age of 24 could mean that they are all post-graduate students, or that they are all undergraduates and one of them is a mature student. Mind you, the quizmaster, Jeremy Paxman, while entertaining is clearly only half-educated, as he appears to be scientifically illiterate.

    • There are countless studies that don’t measure up to the high standards that some health professionals and academics require. This one just happens to be looking at the potential to counter the covid-19 virus. So I find it strange this flawed study even appears on this illustrious forum, what’s the point? …..
      Ahh, just realised why, as Edzard commented :
      “In fact, it is hard these days to find a SCAM that is not touted for COVID-19”.

      So why are you wasting your valuable time Edzard seeking out these so called SCAM type studies? How about being more positive and featuring well designed studies of groups of covid patients that demonstrate significant benefits when using certain nutrients compared to baseline. Are you really saying that Vitamin D, C, Zinc, Selenium, Magnesium and many other NON-SYNTHETIC naturally derived compounds have no value or provide no useful support for the immune system?

      • “So why are you wasting your valuable time Edzard seeking out these so called SCAM type studies?”
        It’s called informing the public, and I happen to believe that, in the realm of SCAM, this is important.
        “How about being more positive and featuring well designed studies of groups of covid patients that demonstrate significant benefits when using certain nutrients compared to baseline.”
        I’d do this with pleasure! Do you know of any?

  • There are good reasons to research further on quercitin/zinc as an antiviral therapy. Of the hundreds of papers on the various topics those below are a quick selection:

    Zinc Antiviral Activity:

    The Role of Zinc in Antiviral Immunity

    https://academic.oup.com/advances/article/10/4/696/5476413

    Zinc Deficiency:

    Globally, 17.3% of the population is at risk for zinc deficiency due to dietary inadequacy; up to 30% of people are at risk in some regions of the world

    https://www.cdc.gov/nutrition/micronutrient-malnutrition/micronutrients/index.html

    Zinc Ionophores:

    Zinc Ionophore Activity of Quercetin and Epigallocatechin-gallate: From Hepa 1-6 Cells to a Liposome Model

    https://pubs.acs.org/doi/10.1021/jf5014633

    Zinc-COVID-10 Perspective:

    The Potential Impact of Zinc Supplementation on COVID-19 Pathogenesis

    https://www.frontiersin.org/articles/10.3389/fimmu.2020.01712/full

    • There certainly do seem to be good reasons to build on these in-vitro and animal studies to investigate a potential therapeutic role here in humans. Sadly the trial that Edzard was looking at was so badly designed that it has been unable to contribute anything much of value here.

      History has taught us the dangers of extrapolating from non-human investigations to clinical practice and overlooking this vital step.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Recent Comments

Note that comments can be edited for up to five minutes after they are first submitted but you must tick the box: “Save my name, email, and website in this browser for the next time I comment.”

The most recent comments from all posts can be seen here.

Archives
Categories