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47

The definition of mortality rate that you've given does not match any practical definition I'm familiar with.* When people talk about the mortality rate of a disease, what they usually mean is the case fatality rate or the death-to-case ratio, which is simply defined as Nd / Ni, where Nd is the number of deaths attributed to the disease over a given time ...


33

If there was close contact, if the 90% rate is accurate, and if occurrence is independent in related individuals, then you would expect 0.10 * 0.10 = 1% of contacts with 2 potentially vulnerable people to result in neither person infected. 1% sounds rare, but rare events happen all the time, and 1% isn't even particularly rare. If you know 100 families, you'...


20

To turn this question on its head, I'd like to propose a different question that the AIDS deniers haven't answered. If HIV were not the cause of AIDS, why would anti-retroviral therapy be so successful in preventing the disease? Each of the meds in the cocktails that stave off AIDS limit the ability of the virus - the HIV virus - to reproduce. It can be ...


20

The equation you use for mortality is only really useful in the very long term for a known disease, when most cases have resolved. It's not very informative in the short-term, when the vast majority of total cases are neither deaths nor recoveries. Right now, the vast majority of people diagnosed have a mild illness and are very unlikely to die, but it ...


20

One of the primary purposes of corticosteroids is to suppress immune activity and inflammation: that's exactly why they are used in asthma. Of course the immune system has an actual job besides causing nuisance inflammation: fighting infection. For some infections, the harm to the infected person caused by the immune reaction itself is worse than that of ...


19

With respect to your peer-reviewed journal article, Frontiers isn't a particularly well-regarded journal series. AIDS denialism is alive and well, but there's a massive body of evidence pointing to HIV infection as the cause of AIDS. Just as a starting point, consider this 2010 report from the NIH. One should also consider what would be required for this ...


19

The only approved inhaled vaccine is the flu vaccine delivered intra-nasally. It uses a live attenuated virus. There are a whole list of people who should not receive it because it's a live virus, and it works better for children, but only is 40% effective for adults. The main issue is The intranasal LAIV, recommended for children above the age of 2 ...


15

What your government is proposing is a lot less than what was actually done in China. There, and perhaps that is still the case, large numbers of asymptomatic infected people were housed together in halls with only social separation between them, and masks to prevent others from infecting others. Your government is proposing to house the asymptomatic ...


14

To add to @BryanKrause's answer re: rare events happen all the time, the children are not out of the woods yet. The mean incubation time for a primary VZV infection (the clinical syndrome known as chicken pox) is 14 days, but often lasts up to 21 days (see Murray Medical Microbiology, Ch. 53). The father is infectious while shedding virus, usually via the ...


14

I'd like to chime in with an explanation of what exactly is wrong with the calculation offered in the question, rather than just saying "it's a wrong formula". Understanding the "whys" of the fallacy is important. So I'll try to answer your question from the math point of view. TL;DR: The root cause of the fallacy is that recovery takes much longer that ...


12

The confusion exists because there are conflicting pronouncements from various authoritative sources but also conflicting pronouncements from the same authority. Covid-19 is a respiratory infection spread by droplets that can be aerosolized (nuclear droplets) in certain situations such as by flushing toilets or in certain medical procedures such as ...


10

Since it seems unlikely that these data are available already from the novel virus, I'll refer to other coronavirus strains associated with outbreaks, the SARS-CoV coronavirus associated with an outbreak in 2003 and MERS-CoV. In reference to the stability of the virus outside the body for SARS-CoV, the WHO consensus document said: Data from the Chinese ...


9

This is a very interesting question. It's also highly speculative, and vague (what does "a doctor... gives them any medicine necessary to protect them from other diseases that might be lurking in their body" mean? Does it mean they treat the symptoms of AIDS (weight loss, diarrhea, etc?) If it does, then the difference between not treating HIV but ...


9

Won't this (having a flu vaccine every year) put them in an uncharted territory as far as effects on the immune systems are concerned within a couple of decades? No You are exposed to and develop a memory response to many, many more pathogens than vaccines. Your collective immune memory from natural exposure to a pathogen is much, much larger than from ...


8

Short Answer HIV is a virus and when the HIV virus has invaded the body it becomes an infection (specifically an STI only if and when transmitted through sexual contact). Whilst the terms STI and STD are often used interchangeably, really and truthfully, they are different. A sexually transmitted virus is an STI when inside the body, and an STI is not ...


8

Apart from not getting infected due to pure chance (as mentioned already) there is one highly probable explanation (explanation, not overall chance). People get, but don't show it: asymptomatic infection Asymptomatic infection is unusual, but some cases are so mild, they go unrecognised. The primary viraemic phase is followed by a secondary viraemia to the ...


8

The virus causing COVID-19 infects the respiratory tract. It is spread in droplets of moisture when an infected person sneezes, coughs, and exhales. These droplets can be inhaled directly and can also end up on surfaces, where they can be picked up on your hands and then spread to your face. The WHO recommends hand washing and avoiding touching your face ...


7

This is a great question, an area of active debate, and a personal interest of mine. I actually just did a presentation on this, so this answer will probably have more information in it than you need, but I'll add it for completeness. Fever as an Adaptive Response The first important thing to know about fever is that it is something your body initiates ...


7

The Hepatitis B core antibody test is positive for IgG but negative for IgM indicating that you had the hepatitis B infection a while ago. The negative hepatitis B surface antigen test means that they are not detecting the hepatitis B in your blood when testing for the virus surface antigen. This means you've successfully cleared the infection to a very low ...


7

To provide a brief answer, as I think a sufficient answer would be far beyond the scope of this site, the symptoms that are "generic" to the common colds are all caused by the body's response to a pathogen (it's why they are generic). Specific pathogens tend to cause additional symptoms on top of that, some of which seem to be directly related to viral ...


7

Are betadine mouthwashes really effective against COVID-19? In vitro (test tubes/culture plates) studies do show that providone iodine does kill viruses similar to SARS-CoV-2 after sufficient exposure (just as bleach and ethyl/isopropyl alcohol do.) The answer in vivo (in humans or animals) is unknown. (N.B.: That's, unknown, as in, you should probably ...


6

The herpes virus responsible for chickenpox, Varicella zoster lays dormant in nerves after the chickenpox outbreak. Shingles (called herpes zoster) break out in the region affected by that nerve or nerves, which is also why shingles are usually restricted to one body side (as nerves don't cross the spine). [NHS page on shingles] Spreading the virus to ...


6

DaveL already covered the Zika aspects, so I'll just add this. Microcephaly is a birth defect that happens to developing fetuses, not children. Your children were safe from microcephaly the day they were born without it. http://www.cdc.gov/ncbddd/birthdefects/microcephaly.html


6

Yes. Gene therapy is an active area of research; most gene therapy approaches that are studied use some sort of viral vector, those that don't are more the exception and it is unclear how several of those methods would be applied clinically. There have already been clinical trials of gene therapy with viral vectors, with mixed success. Edelstein, M. L., ...


6

This was answered very well by @anongoodnurse in Biology.SE question What are the effects of the common cold in an immunodeficient person? plus there was a study by Bowden (1997) which indicated that: rhinovirus was responsible for 25% of community-acquired VRIs [viral respiratory infections] among bone marrow transplant recipients. In one small study by ...


6

If I get infected once with the virus which causes a common cold, does that mean I will not get infected with the same strain of the virus ever in my lifetime? It depends on quirks of your immune system and the viral load you're exposed to, but in theory (based on vaccination and other studies), presence of the virus will trigger a suppressive response, ...


6

Here's an article that I found helpful, to understand why washing hands with soap is so helpful, and how it helps (Pall Thordarson is a professor of chemistry at the University of New South Wales, Sydney): Why does soap work so well on the Sars-CoV-2, the coronavirus and indeed most viruses? The short story: because the virus is a self-assembled ...


6

If you’re young and healthy with only mild symptoms, your doctor will likely advise you to isolate yourself at home and to limit contact with others in your household. You’ll likely be advised to rest, stay well hydrated, and to closely monitor your symptoms. This means that if you have mild symptoms, yes, you will eventually "cure" yourself, the same way ...


6

Because we know its genomic sequence. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2720273/: Using fixed and frozen lung tissue of 1918 influenza victims, the complete genomic sequence of the 1918 influenza virus has been deduced. Sequence and phylogenetic analysis of the completed 1918 influenza virus genes shows them to be the most avian-like among the ...


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