cdc.gov website review

42 files are served with short cache lifetimes, so returning visitors download them again (3.0 MB).

4 files block the first paint until they finish downloading. Deferring or inlining them could save about 3.3 s.

Your mobile performance score is 60 (desktop: 82). Pages that score under 90 lose visitors before the first paint.

About 112 KiB of JavaScript is downloaded but never used on this page. Google estimates it would make the page about 600 ms faster on a phone.

41 KiB could be saved by minifying JavaScript.

A phone's processor spends 2.3 s on main-thread work while loading, 993 ms of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

3 third-party services load with your homepage (Google Tag Manager, digitalgov.gov and Google Analytics), adding 165 KiB and 223 ms of main-thread time.

Web fonts hide text while they load. Setting font-display: swap shows text immediately (about 200 ms).

About 39 KiB of CSS is downloaded but never applied on this page. Google estimates it would make the page about 150 ms faster on a phone.

3 images could be 122 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen.

7 long tasks block the main thread while loading, the longest for 117 ms. During a long task the page ignores taps.

Critical files load one after another instead of in parallel (3 chains). Preconnecting to key origins and preloading the hero image shortens the chain.

Scripts make the browser recalculate the layout repeatedly while the page loads, which wastes processor time on phones.

Real Chrome users on phones do not pass Google's Core Web Vitals on this page (28-day field data from the Chrome UX Report (opens in a new tab)). Google uses this in ranking.

Your largest element takes 16.6 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the image “Classroom with Ebola prevention guidance written on a chalk…”.

The page becomes fully interactive after 16.9 s. Good is under 3.8 s.

Visually, the page fills in at 9.9 s (Speed Index). Good is under 3.4 s.

Real visitors wait 1.1 s for your server to start answering (75th percentile). Good is under 800 ms.

The first text or image appears after 2.9 s on a phone. Good is under 1.8 s.

7 images have no width and height attributes, so the layout jumps as each one loads.

Over the last 25 four-week periods to 2026-10-03, real Chrome visitors' tap response (inp) went from 110 ms to 110 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Over the last 25 four-week periods to 2026-10-03, real Chrome visitors' largest content (lcp) went from 1.8 s to 2.0 s at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Your homepage downloads 3.1 MB in 50 requests on a phone: images 2.4 MB (16), scripts 367 KiB (15) and fonts 342 KiB (9). Under 2 MB keeps phones on slow connections fast.

9 images (1.4 MB) are JPEG, PNG or GIF. The same pictures as WebP or AVIF are usually much smaller at the same quality, and every current browser shows them.

1 image further down the page (337 KiB) download before anyone scrolls to it. Adding loading="lazy" lets the first screen load first.

By the Sustainable Web Design model, a visit to your homepage emits about 0.89 g of CO₂e: 106.6 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

3 elements have a tabindex above 0, which scrambles the keyboard order.

All page content should be contained by landmarks: 5 elements on the page fail this check, rated moderate by axe-core.

Landmarks should have a unique role or role/label/title (i.e. accessible name) combination: 3 elements on the page fail this check, rated moderate by axe-core.

Contentinfo landmark should not be contained in another landmark: 1 element on the page fails this check, rated moderate by axe-core.

Document should not have more than one banner landmark: 1 element on the page fails this check, rated moderate by axe-core.

Document should not have more than one contentinfo landmark: 1 element on the page fails this check, rated moderate by axe-core.

Page should contain a level-one heading: 1 element on the page fails this check, rated moderate by axe-core.

The skip-link target should exist and be focusable: 1 element on the page fails this check, rated moderate by axe-core.

9 visible links have no text or label, so screen readers cannot say where they go.

No meta description, so Google writes its own snippet from whatever text it finds.

There is no <h1>, so neither visitors nor Google get a clear main headline.

No structured data (JSON-LD), so Google can't show rich results such as your logo, ratings or FAQs.

No Open Graph image (also missing: og:description), so links shared on LinkedIn, Slack or Facebook show no preview picture.

3 links use generic text like “click here” or “learn more”, which tells Google nothing about the page behind them.

The homepage links to 221 pages on cdc.gov and 23 external pages.

There is no Organization (or LocalBusiness) JSON-LD, so search engines and AI assistants have no machine-readable facts about who runs the site: its name, logo, profiles and contact details.

There is no /llms.txt, a short Markdown guide to your key pages for AI tools (llmstxt.org). It is optional and few AI tools read it yet, so treat it as a cheap extra.

/index.html and / all use the title “Centers for Disease Control and Prevention | CDC”. Search engines can't tell which page to show for a search, so each competes with the others.

/spanish and / have no meta description, so Google writes the search snippet from whatever text it finds.

Your homepage links to 4 pages by a URL that isn't their canonical one, for example /spanish, whose canonical is /spanish/index.html. Linking straight to the canonical URL saves crawlers a detour and keeps ranking signals on one address.

/spanish and / have no <h1> headline, so visitors and search engines get no clear main topic.

We fetched 15 pages linked from your homepage (of 72 found) and read each the way a search engine does.

3 images failed to load on a phone, for example https://www.cdc.gov/homepage/images/banner/2026/ebola-outbreak-mobile.jpg.

4 of 18 tappable elements near the top of the page are smaller than 24 px, hard to hit with a thumb.

No Content-Security-Policy header, the main browser-side defence against injected scripts.

Neither X-Frame-Options nor a CSP frame-ancestors policy is set, so any site can embed yours in a frame.

X-Content-Type-Options: nosniff is missing, so browsers may guess file types.

Opening https://cdc.gov goes through 2 redirects before the homepage loads.

No Referrer-Policy header, so full URLs can leak to the sites you link to.

No Permissions-Policy header to switch off camera, microphone and location for embedded content.

There is no /.well-known/security.txt telling researchers how to report a security problem to you.

cdc.gov has no CAA record, so any certificate authority may issue a certificate for it. A CAA record naming your provider (for example letsencrypt.org) closes that door.

On a phone, there is no call to action on the first screen: visitors have to scroll to find out what to do next.

No testimonials, customer logos, ratings or customer counts on the homepage: nothing tells a new visitor that others already trust you.

No analytics or tag manager detected in the HTML, so you can't measure whether any of these fixes work.

The homepage has only about 119 words of visible text; thin pages give Google and first-time buyers little to go on.

No guarantee or risk reducer (money-back, free trial, no credit card) is mentioned, which is often what tips a hesitant visitor.

Email authentication: SPF record 25 points, plus 15 when it ends in -all (10 for ~all); DMARC record 25, plus 25 for a reject policy (15 for quarantine); a DKIM key on a common selector 10.

Before a visitor clicks anything, the page loads Google Analytics and Google Tag Manager (measured from a US location before any click). No consent tool was detected. Visitors from the EU, UK and several US states must be asked first.

Opening the homepage sets 11 cookies (measured from a US location before any click).

No known cookie consent tool loads with the page. Some sites build their own banner, and some only show one to visitors from the EU.

Loading the homepage contacts 3 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.