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The bigger question I have is when will we be ready to confidently claim that the vaccine doesn’t just prevent symptoms but also prevents spread? (Edit: at the

• maxerickson 6y ago
  From the phase 3 trials you'd absolutely expect cases to occur after vaccinations. That's what the 95% efficacy after 2 doses means, that 5% of people had symptomatic infections. Hopefully it is the case that the 5% are people that have a weak response to the vaccine and the remainder mostly aren't infectious. They can study this by monitoring for asymptomatic infections (I don't know if they are going to or not).
  • doktorhladnjak 6y ago
    95% effectiveness does not mean 5% of people had symptomatic infections. It means there were 20 times more infections in the placebo group compared to control. If you gave the vaccine to 1000 people and placebo to 1000 people, and 100 of the placebo and 5 of the treatment group got sick, that's 95% effective, as is if all 1000 in the control group got COVID and only 50 in the treatment group.
    • TheGallopedHigh 6y ago
      You’re saying the same thing as the parent comment.
      • dtech 6y ago
        Parent said 5% had symptomatic infections, 50 in this example, while the correct number is 0.5% percent or 5 people.
    • maxerickson 6y ago
      Yep, thanks for clarifying.
• anonytrary 6y ago
  These vaccines do not prevent spread! They decrease the probability of symptoms, and with any coronavirus, the main vector of spread is going to be through symptoms (coughing, sneezing, etc.). This means that if you are vaccinated, you will be less likely to spread the virus, but you must still wear a mask in order to protect those around you!
  • JamesBarney 6y ago
    Source? Most other vaccines prevent spread. Why don't these?
    • zkms 6y ago
      tl;dr per this Nature article, there's different type of antibody responses, intramuscular vaccines are better at inducing the flavor of antibody that works in the lower respiratory tract (which is excellent at attenuating disease severity) but not the kind that works in the upper respiratory tract. Also afaict, sars 2.0 reproduces in the upper respiratory tract, and it's this type of reproduction that allows for disease spread. i'm not a virologist nor an immunologist but this is my understanding of the situation. https://www.nature.com/articles/s41586-020-2798-3 https://www.nature.com/articles/s41586-020-2798-3 > it is important to note that natural infection induces both mucosal antibody responses (secretory immunoglobulin A (IgA)) and systemic antibody responses (IgG). The upper respiratory tract is thought to be mainly protected by secretory IgA, whereas the lower respiratory tract is thought to be mainly protected by IgG27,28,29. Vaccines that are administered intramuscularly or intradermally induce mainly IgG, and no secretory IgA30. It is therefore possible that most vaccines currently in development induce disease-preventing or disease-attenuating immunity, but not necessarily sterilizing immunity (Fig. 2). > The lower human respiratory tract is thought to be mostly protected by IgG (IgG1 is most prevalent), the main type of antibody in serum, which is transported into the lung. The upper respiratory tract is thought to be mostly protected by secretory IgA1 (sIgA1). a, Natural infection with respiratory viruses induces both a systemic immune response, dominated by IgG1, as well as a mucosal immune response in the upper respiratory tract that is dominated by sIgA1. This process can lead to sterilizing immunity for many respiratory viruses. b, Intramuscular or intradermal vaccination leads in many cases to a strong induction of serum IgG but not to an induction of mucosal IgA. Although some IgG can also be found on the mucosal surfaces of the upper respiratory tract, the lack of sIgA often leaves an individual vulnerable to infection of the upper respiratory tract. c, Intranasal vaccination can efficiently induce mucosal antibody responses, thereby potentially providing sterilizing immunity in the upper respiratory tract. However, systemic immune responses are often lower after this type of vaccination. Currently, all SARS-CoV-2 vaccine candidates in clinical development are administered intramuscularly, and very few of the more than 180 vaccine candidates in development are designed to induce mucosal immunity. Although mucosal immunity might not be required to protect from severe or even symptomatic disease, it could be required to achieve optimal protection from infection and onward transmission of SARS-CoV-2.
• toast0 6y ago
  None of the data you'd need to have policies based on calculated immunity is going to come quickly, if at all. I don't think it's reasonable to try to run an open economy for those who are likely immune and a parallel economy for those who are unknown. There's no way anyone can verify any of that in a day to day setting. I would expect that some international borders might reduce quarantine requirements if you can show evidence of probable immunity, but not right away.
• nradov 6y ago
  Reopening the economy or not is a political choice and doesn't necessarily depend on vaccine effectiveness. The economy in Florida has been pretty much open since September. We can argue about whether that is wise but the reality is they are open today.
  • fsflover 6y ago
    The question was not about wrong political choices, but about the right ones.
    • newsclues 6y ago
      But how do you evaluate right? Public health, economic, liberty, community cohesion?
      • fsflover 6y ago
        Those compatible with the scientific research.
        • sonotmyname 6y ago
          Which scientific research? That which only takes the virus related deaths into account, or that which balances other factors such as depression, suicide, substance and spousal abuse, and long term economic factors?
          • fsflover 6y ago
            At least whatever does not contradict all scientific results.
  • elicash 6y ago
    There’s truth to this, but it’s more complicated. In my neighborhood, even if our mayor “opened” things back up, very few would be willing to, say, dine indoors. I can say this confidently because we were less locked down in the late summer. It’s not just a political choice.
• iso1210 6y ago
  Israel has managed to give the first shot to 20% of its population, and at this rate will be into herd immunity territory by the end of the month. As far as pressures on healthcare systems though, once over 65s have been vaccinated (and the northern winter ends) the pressures pretty much vanish. > Similar to how we’ve never really admitted that people who’ve had COVID are immune and can no longer spread it. Well we don't know that. In many cases the virus reproduces and spreads without any symptoms. If the spread occurs before the immune system kicks in you could still be a carrier even though the vaccine makes your symptoms pretty much zero.
  • Aachen 6y ago
    "once winter ends" I've been wondering about that. In June things were just great, but at the same time our health agency (RIVM) claims COVID-19 is not affected by seasons. Are they lying (since they're saying "is not" instead of "might not" / "unknown"), or was what happened around June a coincidence?
    • GuB-42 6y ago
      I can't believe it is not a bit seasonal, whatever the reason is. First wave ended in June in the northern hemisphere and started in the southern hemisphere at about the same time. We are seeing a similar shift in the second wave. It can be a coincidence but since people are more likely to stay inside when it is cold outside, and transmission is more likely inside, it makes sense.
      • hutzlibu 6y ago
        "It can be a coincidence" Since the cold season is usually when it is cold outside, yeah. Might be more than coincidence.
    • iso1210 6y ago
      More non-covid hospital pressure in winter. More people inside.
    • graeme 6y ago