For covid-19, data has been coming out. Two things to keep in mind are the incubation period and the latent period. The incubation period is the time from when the individual is infected to when they show symptoms, although there are asymptomatic cases where no symptoms are experienced at all.
The average incubation period is 3 days, but it can be as short as 2 days or maybe as long as 21 days or even 24 days. The upper end is rare. Quarantine for 14 days was assumed to be sufficient for nearly all patients. Even a quarantine of less than that, if implemented strictly and widely, presumably would eliminate most infections. Is that true?
More important is the latent period. This is how long it takes from being infected to the onset of symptoms. Keep in mind that, as I understand it, covid-19 is not more contagious than the common flu with any single exposure. Rather, there is a longer potential exposure period which translates as a higher infection rate.
It’s not clear how long one carries the virus and can pass it on to others. Doctors detected the RNA of the virus in the lungs 20 days after infection. And in a study, the pathogen was found in the respiratory tract for much longer, upwards of 37 days. However, carrying the virus doesn’t necessarily mean one is infectious.
For mild cases which is most cases, the infectious period following symptoms doesn’t likely last more than 10 days, even as the virus still can be detected. To demonstrate this, researchers used samples from patients (sputum, blood, urine, stool) to try to grow the virus. On day 8, they failed to do so with patients of mild infections.
So, the fact that some can test positive for weeks might be largely irrelevant. Most patients stop what is called viral shedding in the first 5 days, although in a minority of patients with severe sickness it can go some days beyond that. The extreme cases involved pneumonia and the viral shedding continued for 10-11 days. Still, generally speaking, the most infectious period is those first few days.
Also, keep in mind that not everyone is equally infectious. An elderly couple went on a cruise ship together for a couple of weeks. The wife got infected and presumably was sick for the entire two weeks and yet the husband remained free of infection.
Someone with symptoms may infect no one else while someone without symptoms could easily infect many. It is about 1.2% of covid-19 patients that show no symptoms. On the Diamond Princess cruise ship, 322 of 621 people tested positive with no symptoms. That makes containment difficult, especially with limited ability to do testing.
About symptoms, here is a key piece of info. In a small but significant number of cases, there are no symptoms at all. In many other cases, the symptoms are minor or even atypical. We mostly hear from the media about the respiratory problems, but it can be seen in other ways. Nearly half (48.5%) of patients had digestive issues such as diarrhea, vomiting, and abdominal pain. And about 7% showed no respiratory symptoms at all.
There are other symptoms as well. Most recently, it’s been found that loss of taste and smell can be a sign of infection. About half of patients, in one cluster from Germany, experienced a change in smell or taste. Sensory loss usually follows respiratory symptoms, although not always. Another symptom is redness around the eyes, as seen in some of the worst cases.
Those without the typical respiratory problems and higher temperature don’t see a doctor or only do so much later. This can actually make these cases more severe with a longer recovery period. Yet for some reason, few people are talking about the full spectrum of potential symptoms. In many lists of symptoms, gastrointestinal distress is not mentioned at all. And the loss of senses is only now being reported on.
Bonus info: A mouse study showed that ketosis has protectin against influenza (flu). Coronavirus is different in many ways, but the body deals with viruses through the same basic mechanisms. Ketosis causes the body to produce a special kind of T cell in the lungs and also a protective layer of mucose in the lungs. The survival rate of mice was higher for the mice on a keto diet.
This might be a similar reason why ketosis is inefficient in producing excess heat. Ben Bikman speculates this has to do with the time of year, winter, when ketosis tends to happen. While fasting or in dietary restriction during winter, it would be useful for both the body to produce extra heat and for the immune system to shift into higher functioning.
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‘Covid-19 most infectious in early days’
by Sumitra Debroy & Malathy Iyer
Lost Sense of Smell May Be Peculiar Clue to Coronavirus Infection
by Roni Caryn Rabin
Study: Nearly half of COVID-19 patients experience digestive issues
by Joseph Guzman