munity is achieved <em>with a vaccine</em>. Trying to achieve &quot;natural herd immunity&quot; by letting folks get infected is a <em>terrible</em> idea. (But not for the reason you may think! We&#39;ll explain later.)</p>

	<p>Now, let&#39;s play the SEIR Model again, but showing R<sub>0</sub>, R over time, and the herd immunity threshold:</p>

	<div class="sim">
	        <iframe src="sim/?stage=epi-7" width="800" height="540"></iframe>
	</div>

	<p><strong>NOTE: Total cases <em>does not stop</em> at herd