Is this study stating red algae reduces cold virus by 92% believable?

Question

I was using this spray meant to hasten recovery from the common cold. This study, sponsored by the pharmaceutical company that produces the spray, stated it reduced virus by 92%, and so shortens the duration of the common cold.

Meanwhile a doctor told me that these kinds of things don't work.

Does someone have some perspective on this? Is this a believable study? Was it well designed, and has it been duplicated?

If so, why wouldn't the pharmaceutical produced a certified and expensive drug instead of a no-prescription drug?

Answer 1

Looking at this from the perspective of an infectious disease epidemiologist, the kind of person who often reads (and occasionally runs) studies of this type, I'm skeptical. A number of reasons why:

• The only results are a synopsis. More details and data are apparently available, but there is no manuscript, and their "Transparency Policy" has a lot of caveats in it.
• It's not a peer reviewed study.
• Their treatment protocol is oddly variable - 4 mandatory days plus a possible additional six days based on...?
• Again, since they're not providing tables, this gets a little frustrating to try to consider, but their treatment arm is fairly heavily skewed toward women - they claim it's similar in the control arm, but they won't show you how similar.
• They fail at their primary endpoint, being the mean number of symptoms reported between the treatment and control. The mean number of symptoms are about half-a-symptom less between the treatment and control arms, but the result isn't statistically significant, they do some statistical adjustment I'm a little skeptical of - because they don't describe it - and they end up using somewhat...loose...language like "was a strong trend in favour of Bisolviral®."
• This is all based on patient self-report of symptoms, and interestingly, there's absolutely not an effect for self-reported assessment of efficacy between the treatment and control arms. Further, looking at viral load assays, there's also no biological evidence that anything is happening.

I can't find the specific language about the 92% claim you cite in your question, but my assessment of the overall evidence that this compound works would be "Faint and preliminary, at best".