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15 votes
Accepted

How did the Spanish Flu disappear?

It's didn't disappear. It's still around today, over 100 years later. The 1918 influenza virus is the parent virus for all the human seasonal influenza viruses that are around today, as well as for ...
iayork's user avatar
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9 votes
Accepted

Does vaccination make the immune system "lazy"?

Contrary to many beliefs our immune system needs no "training". It is permanently active and confronted with dozens to hundreds of antigens in our food, from dust we inhale and so on. This all happens ...
Chris's user avatar
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9 votes
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Is COVID-19 more deadly than swine flu?

“Swine flu” is an obsolete name. The official name for the virus that was briefly called “swine flu” is “H1N1pdm09”. H1N1pdm09 has a mortality rate of around 0.01-0.1%. That’s roughly 10- to 20-...
iayork's user avatar
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8 votes

Vero cells and Influenza

In addition to @David's answer, the viruses in this paper were specifically grown in Vero cells because of their lack of interferon expression1,2, which the authors were looking at for examining ...
bob1's user avatar
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7 votes
Accepted

For how long can influenza survive on a piece of paper?

Perhaps just eight to 12 hours. Both influenza A and B viruses survived for 24-48 hr on hard, nonporous surfaces such as stainless steel and plastic but survived for less than 8-12 hr on cloth, ...
iayork's user avatar
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4 votes

How would a virus “evolve” if someone is infected with both the omicron and delta variants at the same time?

Basically your options 1 and 2 are the the only likely outcomes from a co-infection with two SARS-CoV-2 viruses. There is a 3rd option, which is that there is a co-infection, producing some amount of ...
bob1's user avatar
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4 votes

How long does immunity to influenza last when contracting the disease vs vaccination

The effect on adaptive immunity are often stronger when contracting the flu than for getting the flu vaccination. The backside of this is that the flu is a quite dangerous disease which could end ...
Chris's user avatar
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4 votes
Accepted

What makes viruses like the flu and covid so tolerant of mutations compared to most other viruses?

This is actually a far more complex question than it might seem on the surface. It's something that has been noted for quite some time by virologists - and it isn't just RNA viruses that do this. ...
bob1's user avatar
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3 votes

What makes viruses like the flu and covid so tolerant of mutations compared to most other viruses?

One consideration is that influenza viruses and coronaviruses are RNA viruses. While DNA viruses are generally dependent on the host's replicative enzymes, which have evolved low error rates for host ...
canadianer's user avatar
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2 votes
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Amino acid substitutions near the receptor binding site HA protein in type A H3N2 influenza strains?

Short answer: Yes, 156 is generally considered "near" the RBS, e.g. in this paper you can see it mapped onto the structure. For a more general answer, you'll need to sit down and stare at 3D models ...
iayork's user avatar
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2 votes
Accepted

How does one predict how large of an effect on antigenic drift a substitution in the amino acid sequence of a surface protein of influenza has?

Your understanding of influenza antigenic drift is, unfortunately, hypersimplified and mostly wrong. In particular, your notion that some mutations are more important for antigenic drift because of ...
iayork's user avatar
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2 votes
Accepted

Where can I find hemagglutination inhibition (HI) assay data?

I don't think there's any universal database containing ongoing, widely representative HI assay output. The Antigenic Cartography group has made available some historical datasets that were used in ...
iayork's user avatar
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2 votes

How did the Spanish Flu disappear?

Although the accepted answer is good and very possibly correct, I was never fully convinced by it. It describes a situation where less than a third of the world's population was infected, and yet for ...
Nadav Har'El's user avatar
2 votes
Accepted

Do symptoms indicate 'strength' of someone's immune system?

A person is said to have a weak immune system when he/she gets infected very frequently. Such individuals tend to get more tired than others, their wounds heal way slower than others. You may want to ...
biologist_Jaishree's user avatar
1 vote

How would a virus “evolve” if someone is infected with both the omicron and delta variants at the same time?

bob1's answer describes the general mechanisms very well. One must not forget that the emerging recombinations still underly the pressure of evolution: They need to survive and to spread with a rate ...
Sir Cornflakes's user avatar
1 vote
Accepted

Choosing viruses for influenza vaccine

Again, the full answer is too complex to answer here. The CDC has a broad explanation (Selecting Viruses for the Seasonal Influenza Vaccine) and the WHO has a presentation summarizing the process (The ...
iayork's user avatar
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1 vote
Accepted

What portion of America needs the Flu vaccine for herd immunity effects to become substantial?

Quoting Jhung et al. 2011 talking about H1N1 2009 epidemics Although estimates of R0 from past pandemics vary, the R0 of previous pandemic influenza viruses generally range from 1.5 to 1.8 for the ...
Remi.b's user avatar
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1 vote

How can I perform virus neutralization assay for influenza?

There are a number of different protocols, but the canonical one is published at the WHO Influenza site: SEROLOGICAL DIAGNOSIS OF INFLUENZA BY MICRONEUTRALIZATION ASSAY It gives a detailed, step by ...
iayork's user avatar
  • 14.3k
1 vote

How to calculate the geometric mean titer (GMT) of titers from a haemagglutination assay (influenza)?

Typically "<10" is converted to a number that is below the limit of detection; often "9". After that simply following the instructions you have yields a GMT of 77.9. If you are using spreadsheet ...
iayork's user avatar
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