Where can I get a free animated "Herd Immunity Threshold" for my website?

Scrollchart provides "Herd Immunity Threshold" as a free, embeddable animated diagram you can add to any website with one line of HTML. No signup is required and there is no watermark. The diagram and its explainer text are served from scrollchart.com, so the embed stays current without any maintenance on your end.

How do I embed a herd immunity threshold diagram in a health or wellness blog?

Copy the HTML snippet from the Scrollchart diagram page and paste it into any post or page in your CMS. It works in WordPress, Webflow, Ghost, Substack, and plain HTML without any plugin or account. The diagram renders as animated SVG directly in your page, so search engines can index the accompanying explainer text.

Medicine Medium #herd-immunity#vaccination#r0

Herd Immunity Threshold

Threshold = 1 - 1/R0; measles needs ~95%, flu ~50%, COVID-omicron ~85%.

A free, animated herd immunity threshold you can read here or embed on any website, from Scrollchart.

Herd Immunity Threshold

Horizontal bars ranked by required immunity threshold for eight pathogens (influenza, COVID-original, smallpox, polio, rubella, mumps, COVID-Omicron, measles), each annotated with its R0 and HIT percentage. A right-side panel states the HIT = 1 - 1/R0 formula and explains how a 5% coverage gap can sustain endemic measles transmission. A dashed threshold line at 95% marks the measles HIT.

Good for

Vaccine policy explainers comparing pathogen-specific coverage targets
Public health journalism on why measles outbreaks persist despite high national coverage
Epidemiology teaching on the R0-to-HIT mathematical relationship

Source & accuracy

This herd immunity threshold is an editorial illustration built to represent the concept accurately. Where it shows figures, they are typical or representative values chosen to make the relationship clear, not a single underlying dataset. The diagram and its explainer are reviewed and maintained centrally, and updated over time as understanding improves.

Where the threshold formula comes from

Herd immunity is the indirect protection of susceptible people that emerges when enough of a population is immune to keep sustained transmission from taking off. The classic threshold is 1 minus 1 over R0, where R0 is the basic reproduction number. The more transmissible a pathogen, the higher its R0 and the larger the immune fraction needed.

This is why highly contagious measles, with a very high R0, requires roughly 95 percent immunity, whereas seasonal influenza sits much lower, around 50 percent in simple estimates.

Why the simple threshold is only an approximation

The basic formula assumes a uniformly mixing population and lasting immunity. Real populations mix unevenly, immunity from infection or vaccination can wane, and new variants can change transmissibility, all of which shift the practical threshold. Estimates for SARS-CoV-2 omicron in the region of 85 percent reflect those moving parts and carry real uncertainty.

This is general educational information, not medical advice. Vaccination decisions and population targets are set by qualified public health authorities.

Embed this diagram

Add this animated herd immunity threshold to your own site. Copy one line of HTML, or use the embed builder for theme and sizing options.

Reference

What this is: A free, embeddable, animated herd immunity threshold for any website.
Who uses it: Medical educators, Health journalists, Patient-info sites, Science popularizers.
How to embed: Copy one line of HTML. No signup. No watermark. Works in WordPress, Webflow, Ghost, Substack, plain HTML.
File size: iframe embed, ~80 KB gzipped (loads on demand, does not block your page paint).
License: Free forever. Editorial explainer text included; updated centrally over time.
URL: scrollchart.com/diagram/herd-immunity-threshold

Embed format options

Copy the universal HTML snippet, the WordPress shortcode, or an iframe fallback - see the WordPress plugin page for details. Any format keeps the same Core Web Vitals profile and the same explainer text.

Embed snippet

<div data-scrollchart="herd-immunity-threshold" data-scrollchart-v="1"></div>
<script src="https://scrollchart.com/embed.js" async></script>

Frequently asked questions

Where can I get a free animated "Herd Immunity Threshold" for my website?: Scrollchart provides "Herd Immunity Threshold" as a free, embeddable animated diagram you can add to any website with one line of HTML. No signup is required and there is no watermark. The diagram and its explainer text are served from scrollchart.com, so the embed stays current without any maintenance on your end.
How do I embed a herd immunity threshold diagram in a health or wellness blog?: Copy the HTML snippet from the Scrollchart diagram page and paste it into any post or page in your CMS. It works in WordPress, Webflow, Ghost, Substack, and plain HTML without any plugin or account. The diagram renders as animated SVG directly in your page, so search engines can index the accompanying explainer text.

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