<story><title>Moderna raises 2021 vaccine output forecast to at least 600M doses</title><url>https://www.reuters.com/article/health-coronavirus-vaccines-moderna/update-1-moderna-raises-2021-vaccine-output-forecast-to-at-least-600-mln-doses-idUSL4N2JF30F</url></story><parent_chain><item><author>jhowell</author><text>&amp;gt; In fact, it&amp;#x27;s far from clear&lt;p&gt;Seems clear from my perspective. Two doses are recommend by manufacturers. Anything more or less is pure speculation at best. Why speculate in absence of a way to test your hypothesis?</text></item><item><author>lisper</author><text>&amp;gt; each person needs 2 doses&lt;p&gt;That&amp;#x27;s not quite true.  You need 2 for full effectiveness, but it&amp;#x27;s not like missing the second dose leaves you with no benefit at all.  In fact, it&amp;#x27;s far from clear, from a global perspective, that having twice as many people with less-than-full-effectiveness would not better than half as many people with full effectiveness.</text></item><item><author>nend</author><text>&amp;gt;600M sounds like very very few doses given worldwide population and even western world population.&lt;p&gt;Which is why people are so keen on getting more vaccines approved (in the US and abroad). Pfizer is targeting 1.3B doses manufactured in 2021, 600M from Moderna, which still leaves the world plenty short (remember each person needs 2 doses). It&amp;#x27;s a group effort, and there are additional vaccines under development&amp;#x2F;review that will hopefully contribute to the effort.&lt;p&gt;There&amp;#x27;s also discussion around whether Moderna&amp;#x27;s vaccine can be reduced from 100ml to 50ml while retaining the same efficacy, which would obviously double the amount of doses provided by Moderna.</text></item><item><author>rcardo11</author><text>Are these US only numbers? 600M sounds like very very few doses given worldwide population and even western world population.</text></item></parent_chain><comment><author>cltby</author><text>&amp;gt; Anything more or less is pure speculation at best&lt;p&gt;There are two lines of evidence. The first is empirical. It It appears that one dose of Moderna _is_ highly effective, perhaps 85% or more. Note the treatment-control divergence after about fourteen days  [1]. The second is theoretical. From our ample medical experience with other vaccines, there is strong prior reason to think that one dose is likely to work well, and that a second shot in the distant future would be even better than a second shot after three or four weeks. Booster shots are given a.) as backup for people who don&amp;#x27;t seroconvert after one dose b.) to trigger a secondary immune response. In light of a.), we shouldn&amp;#x27;t be surprised by the 85% number (most people seroconvert; there&amp;#x27;s no partial immunity, you either seroconvert or you don&amp;#x27;t). In light of b.), we should be very skeptical of the four week interval, especially since the secondary response takes about two weeks to develop. It&amp;#x27;s shorter than the interval for every other vaccine.&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;arstechnica.com&amp;#x2F;science&amp;#x2F;2020&amp;#x2F;12&amp;#x2F;fda-releases-data-on-modernas-covid-vaccine-it-looks-good&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;arstechnica.com&amp;#x2F;science&amp;#x2F;2020&amp;#x2F;12&amp;#x2F;fda-releases-data-on...&lt;/a&gt;
[2] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.cdc.gov&amp;#x2F;vaccines&amp;#x2F;schedules&amp;#x2F;hcp&amp;#x2F;imz&amp;#x2F;child-adolescent.html&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.cdc.gov&amp;#x2F;vaccines&amp;#x2F;schedules&amp;#x2F;hcp&amp;#x2F;imz&amp;#x2F;child-adolesc...&lt;/a&gt;</text></comment>
<story><title>Moderna raises 2021 vaccine output forecast to at least 600M doses</title><url>https://www.reuters.com/article/health-coronavirus-vaccines-moderna/update-1-moderna-raises-2021-vaccine-output-forecast-to-at-least-600-mln-doses-idUSL4N2JF30F</url></story><parent_chain><item><author>jhowell</author><text>&amp;gt; In fact, it&amp;#x27;s far from clear&lt;p&gt;Seems clear from my perspective. Two doses are recommend by manufacturers. Anything more or less is pure speculation at best. Why speculate in absence of a way to test your hypothesis?</text></item><item><author>lisper</author><text>&amp;gt; each person needs 2 doses&lt;p&gt;That&amp;#x27;s not quite true.  You need 2 for full effectiveness, but it&amp;#x27;s not like missing the second dose leaves you with no benefit at all.  In fact, it&amp;#x27;s far from clear, from a global perspective, that having twice as many people with less-than-full-effectiveness would not better than half as many people with full effectiveness.</text></item><item><author>nend</author><text>&amp;gt;600M sounds like very very few doses given worldwide population and even western world population.&lt;p&gt;Which is why people are so keen on getting more vaccines approved (in the US and abroad). Pfizer is targeting 1.3B doses manufactured in 2021, 600M from Moderna, which still leaves the world plenty short (remember each person needs 2 doses). It&amp;#x27;s a group effort, and there are additional vaccines under development&amp;#x2F;review that will hopefully contribute to the effort.&lt;p&gt;There&amp;#x27;s also discussion around whether Moderna&amp;#x27;s vaccine can be reduced from 100ml to 50ml while retaining the same efficacy, which would obviously double the amount of doses provided by Moderna.</text></item><item><author>rcardo11</author><text>Are these US only numbers? 600M sounds like very very few doses given worldwide population and even western world population.</text></item></parent_chain><comment><author>BurningFrog</author><text>The manufacturer doesn&amp;#x27;t know anything about this that isn&amp;#x27;t public information.&lt;p&gt;Yes, two doses are almost certainly better than one. But those are not the choices.&lt;p&gt;When there are far fewer doses than the number of people to vaccinate, the question is if it&amp;#x27;s better to give N people 2 shots, or 2N people 1 shot.&lt;p&gt;The test data looks like 1 dose gives ~80% protection vs ~95% for 2 doses. The 2x80% scenario is clearly better than 1x95%.&lt;p&gt;And, of course, everyone would get the second dose as soon as production catches up.</text></comment>