Why certain virus variants are more contagious than others
DEAR DR. ROACH: The newest COVID variant is reputed to be less deadly but highly contagious. What precisely makes one virus variant more contagious than another virus variant? Is it structure, size? -- S.
ANSWER: It’s not size, because all coronaviruses are just about the same size. It is certainly the structure, but a virus has several adaptations that make it more likely to be passed from one person to another. When conditions include a highly persistent virus within a certain population, then, in general, those viruses that have mutations and enable better person-to-person transmission are more likely to be passed on.
Similarly, the strains of viruses that don’t kill their hosts (us) right away are more likely to be passed on, so we generally see more infectious -- but not more deadly -- virus variants, as infections stay around for years. Ideal conditions for a virus are lots of highly infectious viruses being produced for as long a period of time as possible, as well as times when people aren’t as sick that they don’t have to stay at home. Unfortunately, it isn’t always the case that viruses get less deadly over time. There is always a risk for a more contagious and more deadly virus.
The factors that make a virus more contagious are varied. Viruses that can reproduce faster and make more of themselves are favored. Those that contain lots of spike proteins, which attach to human cells and start the process of getting the virus into the cells, are also more likely to spread.
Getting around your body’s immune system (including the potential ability to infect someone who has had COVID before or who has been immunized) is another factor that predicts greater infectiousness.
Being up-to-date with the vaccine, using personal protection (especially masks) and staying away from crowds when risk is high remain the best ways of avoiding infection with SARS-CoV-2, the virus that causes COVID-19.
I suffer from burning mouth syndrome and dry mouth. Have there been any new treatments for these problems? I’ve tried “magic mouthwash,” but it made things worse. I was prescribed 100 mg of gabapentin three times a day, which really started to work, but I could only tolerate it for two months. I also tried Lyrica, but the side effects were too much, and I only took it for five days.
This is a miserable condition. I finally found a toothpaste that doesn’t irritate my mouth further.
DEAR DR. ROACH:
I brush and floss my teeth right after I eat, as food left on my teeth often irritates my mouth. My saliva changes from being a thick paste to over-salivating. The area directly behind my upper front teeth and inside my upper lip burn some days worse than others. I try to avoid overly hot or overly cold food and drink, as well as spicy or acidic foods.
I’ve been to an ENT, my family doctor and my gastroenterologist over this. Are there specialists for this condition? -- K.H.
ANSWER: Burning mouth syndrome is an uncommon condition, frequently misdiagnosed or diagnosed only after many years of, as its name describes, a burning sensation in the mouth without any other diagnosis to explain it. Although a dry mouth sensation is common, objective findings of dry mouth would make me consider another condition -- Sjogren’s syndrome.
Burning mouth syndrome is thought to be a neurological disease. Pregabalin (Lyrica) and gabapentin (Neurontin) are very similar medicines frequently used for pain due to nerve damage (neuropathy). A neurologist would be the expert in managing this unusual condition, although other possible conditions (like the Sjogren’s I mentioned) may require further evaluation, if it has not yet been done.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.