4 ms·

Every vaccine we have developed in the past had reduced transmission. No exceptions. It is scientific blindness to abandon all of our priors and say “who knows

by graeme 6y ago

Every vaccine we have developed in the past had reduced transmission. No exceptions. It is scientific blindness to abandon all of our priors and say “who knows if it reduces transmission?”

runako 6y ago
I'm not suggesting we abandon priors, but Covid does have some novel facts: - apparently high asymptomatic rate - somewhat unpredictable who will get severe case - random neurological symptoms in a respiratory virus And most/all of the vaccines we are using will be the first approved for human use on their respective platforms. It's worth looking at. Also, for a pathogen that is so highly transmissible, it's worth understanding what we mean by "reduced transmission". Is it 10% less? 90%? Surely this would be important to know before following a strategy of vaccinating the young and healthy first. (Especially given the difficulty of doing so in a population that is least likely to suffer serious harm from the pathogen.)
- graeme 6y ago
  The point is we could have vaccinated the young and healthy summer 2020, had we had challenge trials proving efficacy in that group. How could that not have helped? We vaccinated no one in that period as it is.
  - tinus_hn 6y ago
    We didn’t even bother manufacturing vaccines. Even though they were paid in advance.
    - graeme 6y ago
      Because there was no one approved to give them to. Companies could have gone some out if govts had ordered delivery earlier for the age groups in question. It would have sped up subsequent production too.
      - tinus_hn 6y ago
        The orders were placed and guaranteed over half a year ago. Don’t make up excuses.
  - runako 6y ago
    Even a challenge trial would need to be run properly and include enough people to generate useful data. But let's play the opposite. Let's be unscientific and assume an untested vaccine on a novel platform would reduce transmission risk (Edit: if we assume this, why not just assume the candidate vaccine works and just skip the challenge trials too?). Further assume that recruiting enough volunteers for meaningful results would be easy in spring 2020, before the age cohort differences in severity were as established. Given those assumptions, there still needs to be a smaller safety trial before a large challenge trial. BioNTech started those in April, that ended in May. Deployment in the summer is already aggressive, assuming no challenge trials and we had just deployed vaccines shown to be safe in very small trials. But suppose a challenge trial was run rapidly over the next three months (to determine which of the BioNTech candidates was best). Assume this all goes optimally. This plan still assumes the existence of scale manufacturing facilities that likely did not exist last summer. Let's wish that away too, so we have scaled manufacturing capacities to June 2021 levels by May 2020. While we have our magic wand out, let's wave away the fact that the vaccine initially took over 100 days to manufacture, so that in our world we can decide what to produce today and have it ready tomorrow instead of next quarter. So we've got positive challenge trial results in July 2020 with faster-than-2021 production capacity to go to scale. Now, perception-wise, we are asking young healthy people to take a vaccine designed on a novel platform that was rushed through a novel ethics-skirting approval process, for a virus that likely won't seriously harm them if they get it. I'm not sure that would be as effective as people seem to think it is.
oldgradstudent 6y ago
There are exceptions. The Tetanus vaccine targets the toxin, not the pathogen. Some research may indicate that the current a-cellular whooping cough vaccine prevents symptoms, but not transmission. The older vaccine prevented transmission, but had too many side effects. The oral polio vaccine may actually result in outbreaks of the vaccine strain. http://www.emro.who.int/syr/syria-news/polio-outbreak-successfully-stopped.html http://www.emro.who.int/syr/syria-news/polio-outbreak-succes... Claims about prevention of transmission needs to be demonstrated in a trial, not simply asserted.
- maxerickson 6y ago
  So would you expect a vaccine that is targeted at a viral protein to target something other than the viral protein?
  - oldgradstudent 6y ago
    I have no idea. But I see no reason to a-priori assume perfect targeting without a trial. Supposedly, the Pandemrix fiasco happened because the antibodies generated by the vaccine cross reacted with some human proteins. The lengthy drug approval regimen exists not because of some power drunk bureaucrats. It exists because of a long history of dangerous and ineffective drugs that looked really great in theory.
    - graeme 6y ago
      The antibodies in pandremix would have had the same effect had those who were vaccinated been infected by the flu instead, except the narcolepsy would have been worse.
      - oldgradstudent 6y ago
        Or another, safer, vaccine could have been used instead.
    - maxerickson 6y ago

by graeme 6y ago

Every vaccine we have developed in the past had reduced transmission. No exceptions. It is scientific blindness to abandon all of our priors and say “who knows if it reduces transmission?”

runako 6y ago

I'm not suggesting we abandon priors, but Covid does have some novel facts: - apparently high asymptomatic rate - somewhat unpredictable who will get severe case - random neurological symptoms in a respiratory virus And most/all of the vaccines we are using will be the first approved for human use on their respective platforms. It's worth looking at. Also, for a pathogen that is so highly transmissible, it's worth understanding what we mean by "reduced transmission". Is it 10% less? 90%? Surely this would be important to know before following a strategy of vaccinating the young and healthy first. (Especially given the difficulty of doing so in a population that is least likely to suffer serious harm from the pathogen.)

graeme 6y ago
The point is we could have vaccinated the young and healthy summer 2020, had we had challenge trials proving efficacy in that group. How could that not have helped? We vaccinated no one in that period as it is.
- tinus_hn 6y ago
  We didn’t even bother manufacturing vaccines. Even though they were paid in advance.
  - graeme 6y ago
    Because there was no one approved to give them to. Companies could have gone some out if govts had ordered delivery earlier for the age groups in question. It would have sped up subsequent production too.
    - tinus_hn 6y ago
      The orders were placed and guaranteed over half a year ago. Don’t make up excuses.
- runako 6y ago
  Even a challenge trial would need to be run properly and include enough people to generate useful data. But let's play the opposite. Let's be unscientific and assume an untested vaccine on a novel platform would reduce transmission risk (Edit: if we assume this, why not just assume the candidate vaccine works and just skip the challenge trials too?). Further assume that recruiting enough volunteers for meaningful results would be easy in spring 2020, before the age cohort differences in severity were as established. Given those assumptions, there still needs to be a smaller safety trial before a large challenge trial. BioNTech started those in April, that ended in May. Deployment in the summer is already aggressive, assuming no challenge trials and we had just deployed vaccines shown to be safe in very small trials. But suppose a challenge trial was run rapidly over the next three months (to determine which of the BioNTech candidates was best). Assume this all goes optimally. This plan still assumes the existence of scale manufacturing facilities that likely did not exist last summer. Let's wish that away too, so we have scaled manufacturing capacities to June 2021 levels by May 2020. While we have our magic wand out, let's wave away the fact that the vaccine initially took over 100 days to manufacture, so that in our world we can decide what to produce today and have it ready tomorrow instead of next quarter. So we've got positive challenge trial results in July 2020 with faster-than-2021 production capacity to go to scale. Now, perception-wise, we are asking young healthy people to take a vaccine designed on a novel platform that was rushed through a novel ethics-skirting approval process, for a virus that likely won't seriously harm them if they get it. I'm not sure that would be as effective as people seem to think it is.

oldgradstudent 6y ago

There are exceptions. The Tetanus vaccine targets the toxin, not the pathogen. Some research may indicate that the current a-cellular whooping cough vaccine prevents symptoms, but not transmission. The older vaccine prevented transmission, but had too many side effects. The oral polio vaccine may actually result in outbreaks of the vaccine strain. http://www.emro.who.int/syr/syria-news/polio-outbreak-successfully-stopped.html http://www.emro.who.int/syr/syria-news/polio-outbreak-succes... Claims about prevention of transmission needs to be demonstrated in a trial, not simply asserted.

maxerickson 6y ago
So would you expect a vaccine that is targeted at a viral protein to target something other than the viral protein?
- oldgradstudent 6y ago
  I have no idea. But I see no reason to a-priori assume perfect targeting without a trial. Supposedly, the Pandemrix fiasco happened because the antibodies generated by the vaccine cross reacted with some human proteins. The lengthy drug approval regimen exists not because of some power drunk bureaucrats. It exists because of a long history of dangerous and ineffective drugs that looked really great in theory.
  - graeme 6y ago
    The antibodies in pandremix would have had the same effect had those who were vaccinated been infected by the flu instead, except the narcolepsy would have been worse.
    - oldgradstudent 6y ago
      Or another, safer, vaccine could have been used instead.
  - maxerickson 6y ago