<story><title>Covid-19 twice as contagious as previously thought – CDC study</title><url>https://thinkpol.ca/2020/04/08/covid-19-twice-contagious-previously-thought/</url></story><parent_chain><item><author>ggm</author><text>I will repeat a question I would love an epidemiologist to reply to: Where is the random background testing? Not testing &amp;quot;I feel unwell&amp;quot; presentations at random, truly going into the field and testing the wider population at random, healthy (believed) or not?&lt;p&gt;You cannot model the IFR accurately from skewed samples and it feels like we aren&amp;#x27;t even doing skewed sampling.</text></item></parent_chain><comment><author>XFrequentist</author><text>Epidemiologist here: you&amp;#x27;re right.&lt;p&gt;Testing resources are in short supply, so testing is being performed to guide clinical decisions (ie sick people) rather than public health&amp;#x2F;science (ie random sample).&lt;p&gt;The handful of serosurveys that have been performed have been quite valuable, but there aren&amp;#x27;t nearly enough.&lt;p&gt;Hopefully this changes as testing capacity ramps up.</text></comment>
<story><title>Covid-19 twice as contagious as previously thought – CDC study</title><url>https://thinkpol.ca/2020/04/08/covid-19-twice-contagious-previously-thought/</url></story><parent_chain><item><author>ggm</author><text>I will repeat a question I would love an epidemiologist to reply to: Where is the random background testing? Not testing &amp;quot;I feel unwell&amp;quot; presentations at random, truly going into the field and testing the wider population at random, healthy (believed) or not?&lt;p&gt;You cannot model the IFR accurately from skewed samples and it feels like we aren&amp;#x27;t even doing skewed sampling.</text></item></parent_chain><comment><author>DesiLurker</author><text>This, unless we do that there is no way to establish true IFR so we wont know until its in hindsight how deadly the covid is? I dont know why this is not the priority 1 for the CDC.&lt;p&gt;on the similar lines, Germany is doing something clever, they are mixing samples to do a kind of binary search with covid tests so they can clear a large number of people with few tests. we should do that without waiting for antibody tests etc. it should be noted that this approach would only work if the infected sample set is very small so the window of doing this is going to close soon.</text></comment>