Ronald B. Turner is a Professor of Pediatrics and Lab Medicine at the Medical University of South Carolina in Charleston, SC. After receiving his medical degree from Southern Illinois University in Springfield, IL in 1976, Turner pursued two fellowships in pediatric infectious disease, first at the University of Virginia in Charlottesville, VA and then at Columbus Children's Hospital in Columbus, OH.

Turner was Assistant Professor of Pediatrics and Pathology at the University of Utah School of Medicine before accepting a position as Associate Professor at MUSC in 1987. He became Professor there in 1997.

Recently, Turner's research demonstrated that a compound called BIRR4 reduces the severity of the common cold. The compound, Turner found, prevents the rhinovirus, which causes about 40 percent of colds in adults, from attaching to cells in the nasal lining. With his colleague Dr. Frederick Hayden of the University of Virginia, Turner ran four separate studies on the effectiveness of BIRR4. The studies showed the compound reduced cold symptoms without dulling the immune response to the virus. Turner reported these results at the 1999 meeting of the American Society for Microbiology.

2.06.01 Ruth Podesta asked:
Why is it that I have never seen a scientific program that shows the positive results of eating peanuts to reduce the symptoms of the common cold? My husband and I read about this many years ago in Prevention magazine and have used this ever since. My husband used to get several colds per year and rarely even gets cold symptoms now. We have passed this use of peanuts on to our children and they have never gotten a serious cold. We eat about a handful or two at the first sign of sniffels or sore throat, and within a day or two we are usually well with no more symptoms.

Turner's response:
I am not aware of any studies of the effectiveness of peanuts as a preventive treatment for the common cold. There are many different factors that may influence the likelihood that someone will have a cold. Before these treatments can be considered effective in scientific terms, they would need to be studied under controlled conditions to assure that the effects were real and that they could in fact be attributed to the nuts and not to other factors.

2.06.01 Thomas C. Lasik asked:
I enjoyed the segment on your studies. It seemed to me that you mentioned vitamin C in passing during your interview. The program and its notes on the PBS Web site talked specifically about Echinacea and Vitamin E. Have you specifically studied vitamin C? If so can you discuss what levels of vitamin C you studied, and is two weeks enough for a compound like a vitamin to really be effective in the system?

Turner's response:
We have not studied vitamin C. The length of time any drug or dietary supplement would need to be taken in advance of the infection in order to have an effect will depend on the mechanism of action and the pharmacologic properties of the material. A drug that has an antiviral effect needs to be present at the site of viral replication in adequate concentration. Similarly a dietary supplement that might act as an antioxidant might need to be present in the nasal mucosa before the onset of oxidant production. For the drugs and dietary supplements that have been studied these requirements should be met by a relatively brief (at most a few days) duration of treatment before infection. If one of these treatments is found to be effective, it may need to be taken throughout the common cold season since in the natural setting the time of exposure to infection will not be known.

2.06.01 Luke asked:
Why are there so many types of cold virus?

Turner's response:
There are probably a couple of reasons why there are so many cold viruses. We now think that the symptoms of the common cold are an unwanted by-product of our body's response to the virus. The same response, and thus the same symptoms, occur when the nose is exposed to a variety of different viruses as well as non-infectious agents like some pollutants in the air. The second reason is that many of the viruses that infect the nose have RNA as their nucleic acid. The replication process for RNA viruses tends to be a bit inaccurate so that mutations occur frequently. When these mutations produce a virus that can replicate but has a slightly different protein shell our bodies may recognize this as a "new" virus. The rhinoviruses which are the most common cause of the colds have over 100 different types that are distinguished by the way our body recognizes the protein shell of the virus.

2.06.01 Victoria F.asked:
So, there are no cures for the common cold as of now? That would mean that I shouldn't go out buy a medicine for any cold symptoms?

Turner's response:
There are no cures for the common cold, however, there are symptomatic treatments that have varying degrees of effectiveness. Simple analgesics like acetaminophen may be useful for pain symptoms like sore throat or headache. The first-generation antihistamines (the antihistamines that are associated with drowsiness) reduce runny nose by about 30% compared to placebo and may also reduce some types of cough. The topical decongestants reduce nasal congestion by as much as 80% for a short period of time. None of these treatments cures the cold. They simply treat the symptoms for some period of time. There is also no evidence that these treatments reduce the frequency of complications of the common cold such as ear or sinus infections or asthma attacks. Whether an individual chooses to use these treatments requires consideration of the severity of the particular symptom, the perceived benefit from taking the treatment and the potential side effects of taking the medication.

2.06.01 Dan Buijs asked:
Is there any anti-viral effectiveness of echinacea or zinc lozenges? What about the long list of scientific studies that support Echinacea (particularly, the German outcome research) and zinc (a study published in Annals of Internal Medicine, Vol. 125, No. 2, pgs. 81-88.)? Does this have to do with varying definitions of "effectiveness"?

Turner's response:
Neither zinc nor echinacea have any anti-viral activity against rhinovirus infections in human volunteers. Zinc has been shown to inhibit rhinovirus in the lab but at concentrations that are quite high and very near the toxic concentrations. Echinacea has been reported to have antiviral activity against other viruses in the lab but to my knowledge has never been tested against rhinovirus.

As noted, both of these treatments have been reported to reduce the symptoms of the common cold. Whether they should be considered "effective" is more subjective. The likelihood that observed differences between the treated and placebo groups is a result of chance can be determined by statistical analysis and this is usually pretty straightforward. Whether a true difference has any meaning for a patient relates to the "clinical significance" of the observation. There is no standard definition for what effect size is clinically significant. Another judgment that affects the assessment of effectiveness is an assessment of the quality of the study. One must judge whether the study asked meaningful questions in a way that eliminates the possibility of bias infavor of one or the other treatment. In my opinion, the studies of zinc and echinacea have not met these criteria and so I do not believe we have convincing evidence that these agents are effective for treatment of the common cold.