107 votes
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What's the evidence against SARS-CoV-2 being engineered by humans?

At the moment, there is very little scientific literature about this, but I found two papers that address the problem and are fairly easy to understand. You can find them in the references. Reference ...
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59 votes
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Are the social-distancing measures implemented against SARS-CoV-2 also suppressing the spread of other viruses?

Yes, this helps as well with other infectious diseases. A good example is the flu, which season was measurably shorter this year than in other years on record. See the figure from the reference 1 for ...
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53 votes
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How does a Coronavirus "test kit" work?

The CDC has made available online its nCoV test kit. Briefly,the kit contains primers and probes for real-time reverse-transcriptase PCR, as well as instructions for appropriate use and (critically) ...
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48 votes

Why do some viruses cease being a problem even though no vaccine or cure is found?

Infections spread in a population when the number of new infections caused by an infected person is greater than or equal to 1. If each infected person spreads the virus to less than 1 person, ...
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43 votes
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Does the genetic sequence of SARS-CoV-2 end with 33 A's?

This is a poly(A) tail, which is a feature found in the majority of eukaryotic RNAs (especially mRNA) and is also not uncommon in RNA viruses (which essentially mimic endogenous mRNA for their own ...
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43 votes
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How many times has SARS-CoV-2 mutated?

This question makes a number of incorrect assumptions and I don't have time to correct them. The short answer is that the virus has mutated probably hundreds of times since it entered humans in late ...
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40 votes

Are the social-distancing measures implemented against SARS-CoV-2 also suppressing the spread of other viruses?

In addition to Chris' answer above, the effect is even more pronounced in Southern Hemisphere countries where flu season started during the pandemic. The New Zealand lockdown and health response ...
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37 votes
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What was the breakthrough behind the “sudden” feasibility of mRNA vaccines in 2020?

Answering my own question after reading the 2018 Nature review article “mRNA vaccines — a new era in vaccinology” The resources and motivation engendered by the COVID-19 pandemic are a major factor in ...
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30 votes
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What does vaccine efficacy mean?

Vaccine efficacy Pfizer's target measures for efficacy (see the study on clinicaltrials.gov) seem to be: Confirmed COVID-19 in Phase 2/3 participants without evidence of infection before vaccination ...
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29 votes

Are fully vaccinated people more likely to not get infected at all with COVID-19?

Yes, this is the effect of the vaccine. A reduction of infections of over 88%, a reduction of severe cases and death by 95% and higher. See reference 1 for the details. Data from the ReCoVAM Study ...
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28 votes
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Loss of taste and smell during a SARS-CoV-2 infection

This is not completely clear to say the least, but there are some hints. Please keep in mind that there was not much time for extensive research, since this disease is still quite new. What seems ...
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25 votes

How does a Coronavirus "test kit" work?

There are actually 3+ types of test kits widely used to diagnose diseases caused by viruses. We can check for the nucleic acid of the virus, the antigen of the virus that would cause an immune ...
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24 votes

What's the evidence against SARS-CoV-2 being engineered by humans?

If you need more [counter]evidence, there's a newer paper "The proximal origin of SARS-CoV-2" by Andersen et al. (March, 17) that touches on the same topic. The paper brings up two reasons ...
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23 votes
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Can you be immune to a coronavirus?

It is hypothesized that exposure to and recovery from SARS-CoV-2 (as with other coronaviruses in humans) would generally result in short-term immunity to this strain, but we do not yet have data on ...
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22 votes
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Why would a 2019-nCoV protein sequence in the NCBI database match a protein submitted in 2018?

2019-nCoV is a virus that originated from the bat (at least this is the current hypothesis). It shows 96% squence similarity to the BatCoV RaTG13 sequence (see reference 1), showing its origin. It ...
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22 votes
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Can the SARS‑CoV‑2 virus mutate in people who have been fully vaccinated?

Since vaccination is not 100% protective against infection (i.e. the virus can sometimes succeed in establishing and replicating in a vaccinated host's body), the answer is yes. Furthermore, since ...
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  • 4,553
21 votes
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What are the environmental conditions for SARS-CoV-2 to survive?

Because "any" Coronavirus is so dangerous, much research have been done on viruses with similar properties. They are called "surrogates". Because nCoV is new, we don't have any studies, so we need to ...
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21 votes
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Coronavirus capsid missing?

Does it really contain a capsid? Yes. Coronaviruses have a capsid, but it's not reminiscent of the polygonal (icosahedral) capsid depicted in the Research Gate picture you referenced. Icosahedral ...
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18 votes
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What are the implications of tigers being susceptible to SARS-CoV-2?

A partial answer, to the question of how the virus might spread to animals I found several references The HongKong dogs, the New York tiger, the Netherlands mink farm and the French cat have been ...
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17 votes
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Is COVID-19 claimed to get less deadly over time? If so, why?

While the data are much too sparse and noisy to give an answer about what is happening to COVID-19's virulence (the technical term for the "deadliness" of an infectious disease), or to forecast what ...
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  • 4,553
17 votes

Why do some viruses cease being a problem even though no vaccine or cure is found?

Bryan Krause's answer addresses the reasons pertinent to SARS and MERS. If you meant those two as examples but are interested in the title question more generally, I can note an additional mechanism. ...
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16 votes
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How do bats survive their own coronaviruses?

It's common for the reservoir host of a zoonotic virus to be tolerant of it. MERS coronavirus appears to cause mild or no disease in dromedary camels ( source ), but kills about 35% of confirmed ...
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15 votes

Do spike-protein-based vaccines undermine the DNA repair system?

While the linked paper presents interesting results, the conclusions must be interpreted in context of their in vitro methods and cannot be readily extrapolated to understand the in vivo effect of ...
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14 votes

Do spike-protein-based vaccines undermine the DNA repair system?

The authors explicitly suggest the first part of your question in their discussion section: indicating that full–length spike–based vaccines may inhibit the recombination of V(D)J in B cells, ...
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  • 3,150
13 votes
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Human Immune Response to COVID-19 Virus

We probably won't really know for certain until we have time to gather more data from survivors. However, infection with existing coronaviruses (including SARS-CoV, genetically very similar to the ...
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13 votes
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Can COVID-19 affect a person a second time?

Short answer: Although there are some reports on this, it is pretty unlikely. It is more likely that patients where released too early from hospital, developed further symptoms later on and got worse, ...
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13 votes
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What is the motivation behind the AAAAGCAUAU GACUAAAAAA of the mRNA SARS-CoV-2 vaccine when encoding its polyadenylated ending?

To enhance stability and translation efficiency according to {1}: The 5′UTR (TEV) [8,21] and 3′ UTR (F-I) of this construct have been shown to enhance stability and translation efficiency, as has the ...
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13 votes
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Do mutations occur while growing virus for preparing inactivated viral vaccine?

Very simply, mutations do occur, as they do for any cultured organism. This is a well recognized problem in many fields of biology where organisms are cultured and remains in particular a problem for ...
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12 votes
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Why are bats the source of dangerous coronavirus pandemics?

The preponderance of links between bat and human pathogens has led to a debate about whether bats disproportionately contribute to emerging viral infections crossing the species barrier into humans (...
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12 votes
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What is the size (diameter) of the SARS-CoV-2 virus?

Electron micrographs of negative-stained 2019-nCoV particles were generally spherical with some pleomorphism (Figure 3). Diameter varied from about 60 to 140 nm. Virus particles had quite distinctive ...
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