Isn't it likely that, as time goes on, that the most successful mutations will result in a virus that is more transmissible, but causes milder (non-fatal) illness? If I remember my evolutionary theory correctly, this combination would result in the most favorable set of characteristics for any parasitic entity (i.e., "don't kill the host").
This is a good question. It is true that in many cases there is a push-pull between virulence and transmissibility. This is particularly true when the contagious period for the virus overlaps with the symptomatic period. If the virus incapacitates its hosts during its period of peak transmissibility, it is going to have a fitness issue.
However, once the virus has transmitted effectively and passed its peak of transmissibility, it really doesn't matter whether it causes some horrible disease, at least not in an evolutionary sense. As an example, HIV has a 99% case-fatality rate when untreated, but it takes literal years to get to that lethal point. There is very little selective pressure on the virus related to that lethality, because it can effectively and successfully spread itself to new hosts without worrying about its current host's ultimate survival. Here, the pressures on transmission and propagation are separated from the pressures on virulence factors.
For SARS-CoV-2, peak transmissibility can occur before symptoms ever appear. At first detection, most eventually severe cases appear relatively mild. Look, for example, at the case of Donald Trump, who was likely the index patient for an outbreak that began in the White House's Rose Garden. By all reports, President Trump basically felt like he had a mild cold going into this event. He tested positive shortly after the ceremony in the Rose Garden, and from that event, 52 additional cases of COVID-19 were generated. That event was on September 26th, so likely between 4 and 7 days after Trump became infected.
He was hospitalized for COVID-19 on October 1st of 2020. By then, the damage was largely done in terms of passing on the virus, and from what we know about the kinetics of such infections, he was probably well past peak transmissibility by that time as well. At that point, the virus he was infected with seems to have been fantastically successful, even compared its fellow relatives in the SARS-CoV-2 strain. 53 is a huge number of cases in a single cluster. If it had killed President Trump after October 1st, this would not have had an impact on its overall evolutionary success.
SARS-CoV-2 has a number of pathogenesis factors, but many of them rely on virus-host interactions and the production of inflammatory signals by the host in order to bring about tissue damage. A lot of the treatments that are used in hospitals for COVID-19 focus on lessening host inflammatory responses, rather than on doing anything to the virus itself. My point in this is that in your severe and potentially fatal cases, the immune system has generally responded, and that response usually takes place after peak transmissibility. It's hard to see what fitness a virus could achieve if it acquired a mutation that reduced these pathogenic effects.
We know that asymptomatic and presymptomatic patients can make a big contribution to the transmission of SARS-CoV-2, also. There are plenty of these patients; the presymptomatic population may substantially overlap with the ~7% who are hospitalized and the ~1% who die.
So overall my point is that a lot of the transmission of this virus is happening well before peak symptoms, and evolutionary pressures are all about transmission. Fit viruses survive to replicate and transmit; unfit viruses do not survive to replicate and transmit. If the virus can do those activities before killing its hosts, then evolution will exert little pressure on whether it kills those hosts or not in the end.
This isn't true for every virus. Some viruses only transmit when the host is symptomatic. Those viruses will probably (but not always) be under evolutionary pressure favoring a reduction in pathogenicity, because the less debilitated the host is, the more likely the virus is to spread. Unfortunately, SARS-CoV-2 isn't a virus of that type.
This doesn't mean all hope is lost for gradual reduction in virulence, but it does mean we have no reason to assume there should be such a reduction. It is possible that there is an overlap between sequence that supports pathogenicity factors and sequence that supports transmission, and that changes to enhance one will compromise the other. If that's the case, then the virus could very well have this kind of trend. But I know of no evidence of such a thing, so I can't assume that it will happen this way.
At the present time, the evidence I have available tells me that the capacity of SARS-CoV-2 to cause disease, and its capacity to infect, survive, replicate, and transmit are not directly linked. So I don't expect it to become less virulent as a result of evolutionary pressure.
And the con was in NYC, where (based on my visit last month) there are free rapid antigen tests widely available. I saw a stand advertising them outside Queens Center mall. It seems pretty easy to get tested in NYC on a regular basis.
It's incredibly easy. There are three vans/trucks that have rapid testing on my street. They also do 24-hr turnaround of PCR. They're 100% free.
The same kind of setup can be found every 10 blocks or so. Near the Javits Center, where the con took place, I know there are a bunch of similar testing vans because I go down to Hudson Yards regularly, which is nearby. Implementing a rapid test requirement for events at Javits might be annoying for organizers, but logistically it is very doable.
You mentioned using higher-quality masks, but then you refer to surgical masks. They are, indeed, better (meaning more protective) than cloth masks, but they aren't the most protective. In late 2021, both N95 and South Korean KF94 certified respirators are available and highly affordable.
I suspect many people will find the KF94s easier to use because they attach with ear loops. The N95 standard requires head straps.
Note that according to tests (e. g. by "The Mask Nerd" Aaron Collins) you can wear these for up to 60 hours with no measurable effect on function (unless you're in a very dirty environment). Just let them "rest" for 24 or 48 hours between wearings, which is long enough for any trapped SARS-CoV-2 to become nonfunctional. That brings the cost of masks that offer excellent protection down to well under a dollar a day--and that last figure assumes you actually leave your home every single day, which is not true for everyone in 2021.
Collins' tests indicate that some of the Chinese-made KN95 respirators are excellent ... and some are barely even filtering. The trouble is that both the US and South Korean governments actually verify the ability of N95 and KF94 respirators to remove 0.3 micron particles. The Chinese government defines a standard, but doesn't regularly test actual products. Also, some of the KN95s on Amazon are just plain counterfeits some anonymous third party is selling.
Yeah, to be honest, I don't know why I said surgical masks rather than also mentioning KN95s and N95s. I think I was concerned that these were too heavy duty for most people, but when has overkill stopped me before? I should have said that surgical masks should be the minimum standard for basic source control while N95-like standards should be used for people particularly concerned about self-protection (for any number of valid reasons).
Good adds here and this will go into Monday's issue.
Oh, yeah, another thing (being verbose today, sorry): the anime con that the Minnesota man attended ended on 22 November. If there was a superspreader event there, we'd have already seen many, many cases. Coincidence? Caught it somewhere else?
Would I get tested, had I attended the con? Yes. Would I be very worried? No.
Note that I did attend a convention, Philcon, that weekend. Seem to have survived. (I actually took a rapid antigen test last weekend, because I was about to do a three-day video shoot this week. Negative.)
To see cases, you have to be testing for cases. For Omicron, that means sequencing. We're not sequencing enough to be able to really detect these.
At this point 6 cases of Omicron variant infection are linked to the con already, as I understand. I don't think it's coincidental that the Minnesota case was a traveler at the convention.
I see that now--as of last night the messaging made it sound like they were. Even so, if we found one linked to the con I think it's wise to assume there are many more. The Minnesota patient's only travel was to NYC, and there's Omicron here apparently in abundance of anywhere else. Local acquisition seems less likely than here in NYC. But we really don't know a lot.
Either way, I don't like the protocols the con was using. Even if it wasn't a major spread event.
Isn't it likely that, as time goes on, that the most successful mutations will result in a virus that is more transmissible, but causes milder (non-fatal) illness? If I remember my evolutionary theory correctly, this combination would result in the most favorable set of characteristics for any parasitic entity (i.e., "don't kill the host").
This is a good question. It is true that in many cases there is a push-pull between virulence and transmissibility. This is particularly true when the contagious period for the virus overlaps with the symptomatic period. If the virus incapacitates its hosts during its period of peak transmissibility, it is going to have a fitness issue.
However, once the virus has transmitted effectively and passed its peak of transmissibility, it really doesn't matter whether it causes some horrible disease, at least not in an evolutionary sense. As an example, HIV has a 99% case-fatality rate when untreated, but it takes literal years to get to that lethal point. There is very little selective pressure on the virus related to that lethality, because it can effectively and successfully spread itself to new hosts without worrying about its current host's ultimate survival. Here, the pressures on transmission and propagation are separated from the pressures on virulence factors.
For SARS-CoV-2, peak transmissibility can occur before symptoms ever appear. At first detection, most eventually severe cases appear relatively mild. Look, for example, at the case of Donald Trump, who was likely the index patient for an outbreak that began in the White House's Rose Garden. By all reports, President Trump basically felt like he had a mild cold going into this event. He tested positive shortly after the ceremony in the Rose Garden, and from that event, 52 additional cases of COVID-19 were generated. That event was on September 26th, so likely between 4 and 7 days after Trump became infected.
He was hospitalized for COVID-19 on October 1st of 2020. By then, the damage was largely done in terms of passing on the virus, and from what we know about the kinetics of such infections, he was probably well past peak transmissibility by that time as well. At that point, the virus he was infected with seems to have been fantastically successful, even compared its fellow relatives in the SARS-CoV-2 strain. 53 is a huge number of cases in a single cluster. If it had killed President Trump after October 1st, this would not have had an impact on its overall evolutionary success.
SARS-CoV-2 has a number of pathogenesis factors, but many of them rely on virus-host interactions and the production of inflammatory signals by the host in order to bring about tissue damage. A lot of the treatments that are used in hospitals for COVID-19 focus on lessening host inflammatory responses, rather than on doing anything to the virus itself. My point in this is that in your severe and potentially fatal cases, the immune system has generally responded, and that response usually takes place after peak transmissibility. It's hard to see what fitness a virus could achieve if it acquired a mutation that reduced these pathogenic effects.
We know that asymptomatic and presymptomatic patients can make a big contribution to the transmission of SARS-CoV-2, also. There are plenty of these patients; the presymptomatic population may substantially overlap with the ~7% who are hospitalized and the ~1% who die.
So overall my point is that a lot of the transmission of this virus is happening well before peak symptoms, and evolutionary pressures are all about transmission. Fit viruses survive to replicate and transmit; unfit viruses do not survive to replicate and transmit. If the virus can do those activities before killing its hosts, then evolution will exert little pressure on whether it kills those hosts or not in the end.
This isn't true for every virus. Some viruses only transmit when the host is symptomatic. Those viruses will probably (but not always) be under evolutionary pressure favoring a reduction in pathogenicity, because the less debilitated the host is, the more likely the virus is to spread. Unfortunately, SARS-CoV-2 isn't a virus of that type.
This doesn't mean all hope is lost for gradual reduction in virulence, but it does mean we have no reason to assume there should be such a reduction. It is possible that there is an overlap between sequence that supports pathogenicity factors and sequence that supports transmission, and that changes to enhance one will compromise the other. If that's the case, then the virus could very well have this kind of trend. But I know of no evidence of such a thing, so I can't assume that it will happen this way.
At the present time, the evidence I have available tells me that the capacity of SARS-CoV-2 to cause disease, and its capacity to infect, survive, replicate, and transmit are not directly linked. So I don't expect it to become less virulent as a result of evolutionary pressure.
And the con was in NYC, where (based on my visit last month) there are free rapid antigen tests widely available. I saw a stand advertising them outside Queens Center mall. It seems pretty easy to get tested in NYC on a regular basis.
It's incredibly easy. There are three vans/trucks that have rapid testing on my street. They also do 24-hr turnaround of PCR. They're 100% free.
The same kind of setup can be found every 10 blocks or so. Near the Javits Center, where the con took place, I know there are a bunch of similar testing vans because I go down to Hudson Yards regularly, which is nearby. Implementing a rapid test requirement for events at Javits might be annoying for organizers, but logistically it is very doable.
Hi, John,
You mentioned using higher-quality masks, but then you refer to surgical masks. They are, indeed, better (meaning more protective) than cloth masks, but they aren't the most protective. In late 2021, both N95 and South Korean KF94 certified respirators are available and highly affordable.
I am paying about $1.20 for my KF94-grade masks from https://kollecteusa.com/
The ones I get are rated at 99.8% removal of the most penetrating particle size range, in actual wear on a human face.
You can also get N95s for under a dollar (!) here: https://shop.projectn95.org/gerson-n95-respirators-3230-box-of-50/p
I suspect many people will find the KF94s easier to use because they attach with ear loops. The N95 standard requires head straps.
Note that according to tests (e. g. by "The Mask Nerd" Aaron Collins) you can wear these for up to 60 hours with no measurable effect on function (unless you're in a very dirty environment). Just let them "rest" for 24 or 48 hours between wearings, which is long enough for any trapped SARS-CoV-2 to become nonfunctional. That brings the cost of masks that offer excellent protection down to well under a dollar a day--and that last figure assumes you actually leave your home every single day, which is not true for everyone in 2021.
Collins' tests indicate that some of the Chinese-made KN95 respirators are excellent ... and some are barely even filtering. The trouble is that both the US and South Korean governments actually verify the ability of N95 and KF94 respirators to remove 0.3 micron particles. The Chinese government defines a standard, but doesn't regularly test actual products. Also, some of the KN95s on Amazon are just plain counterfeits some anonymous third party is selling.
Yeah, to be honest, I don't know why I said surgical masks rather than also mentioning KN95s and N95s. I think I was concerned that these were too heavy duty for most people, but when has overkill stopped me before? I should have said that surgical masks should be the minimum standard for basic source control while N95-like standards should be used for people particularly concerned about self-protection (for any number of valid reasons).
Good adds here and this will go into Monday's issue.
Oh, yeah, another thing (being verbose today, sorry): the anime con that the Minnesota man attended ended on 22 November. If there was a superspreader event there, we'd have already seen many, many cases. Coincidence? Caught it somewhere else?
Would I get tested, had I attended the con? Yes. Would I be very worried? No.
Note that I did attend a convention, Philcon, that weekend. Seem to have survived. (I actually took a rapid antigen test last weekend, because I was about to do a three-day video shoot this week. Negative.)
To see cases, you have to be testing for cases. For Omicron, that means sequencing. We're not sequencing enough to be able to really detect these.
At this point 6 cases of Omicron variant infection are linked to the con already, as I understand. I don't think it's coincidental that the Minnesota case was a traveler at the convention.
No, the five NY cases are NOT linked to the con.
Well, unfortunately in retrospect they've now found some additional positives in the immediate friend circle of the Minnesota case, so there we are.
But oddly, no one else from that con (so far).
I see that now--as of last night the messaging made it sound like they were. Even so, if we found one linked to the con I think it's wise to assume there are many more. The Minnesota patient's only travel was to NYC, and there's Omicron here apparently in abundance of anywhere else. Local acquisition seems less likely than here in NYC. But we really don't know a lot.
Either way, I don't like the protocols the con was using. Even if it wasn't a major spread event.