uation better:</p>

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	        <iframe src="sim/?stage=yrs-3&format=lines&height=640" width="800" height="640"></iframe>
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	<p>Oh.</p>

	<p>Counterintuitively, summer makes the spikes worse <em>and</em> regular! This is because summer reduces new <span class="nowrap"><icon i></icon>s,</span> but that in turn reduces new immune <span class="nowrap"><icon r></icon>s.</span> Which means immunity plummets in the summer, <em>creating</em> large regular spikes in the winter.</p>

	<p>Thank