Error prevention on important forms (3.3.4): For pages that create legal commitments or financial transactions or any other important data submissions, one of the following is true: 1) submissions are reversible, 2) the user has an opportunity to correct errors, and 3) confirmation is available that allows an opportunity to review and correct before submission.
Both sites support multiple languages (English and Spanish), and both include lang="es" on the  element of the Spanish pages. However, on the CDC site, in addition to lang="es" the  element has xml:lang="en". This potentially sends mixed messages to screen readers (is this web page in Spanish or English?) JAWS 13 seems to honor lang rather than xml:lang but I don't know about other screen readers.

Because of this, among the greatest drivers of website accessibility are usability improvements and the reputation boost that it brings—or, alternatively, the lost business that organizations want to avoid as a result of inaccessible websites. According to a survey by the National Business Disability Council at the Viscardi Center, 91 percent of customers say that they’d prefer to shop at a website that prioritizes accessibility.
President George H.W. Bush signed the Americans with Disabilities Act into law July 26, 1990. The ADA prohibits discrimination of people with disabilities and guarantees the same opportunities as everyone else. These opportunities include employment possibilities, purchasing of goods and services and the ability to participate in State and local government programs.

Businesses and nonprofits: in determining whether a particular aid or service would result in an undue burden, a title III entity should take into consideration the nature and cost of the aid or service relative to their size, overall financial resources, and overall expenses. In general, a business or nonprofit with greater resources is expected to do more to ensure effective communication than one with fewer resources. If the entity has a parent company, the administrative and financial relationship, as well as the size, resources, and expenses of the parent company, would also be considered.

My request at this point is if the developers of the plugin could please implement a solution like this so that the plugin can be compliant natively, without me having to jump in and edit the code every time the plugin is updated. It doesn’t need to be this solution exactly, as this is admittedly a bit of a rough fix, but if the buttons could be modified with ADA compliance in mind, it would make things a lot easier for sites that use this and have these requirements to meet.
This is particularly important when working for a government agency or government contractor, as these organizations must follow web accessibility guidelines under Section 508 of the Workforce Rehabilitation Act of 1973. Although ADA and Section 508 compliance are different, the published checklist for Section 508 compliance offers insight into ways to make websites accessible for people with disabilities, and thereby work toward ADA compliance.
Luckily, the international nonprofit World Wide Web Consortium (W3C) brings together smart people who develop open standards to ensure the long-term growth of the Web. They produce recommendations for making websites fair and equally accessible for the highest number of people possible. Their Web Content Accessibility Guidelines (WCAG) 2.1 offer clear guidance for web developers to achieve ADA compliance.

Distinguishable: To assist color-blind users and those with other visual impairments, color is never used as the sole means of conveying information or prompting the user. Audio lasting more than 3 seconds can be paused, or the volume can be controlled independently of the system volume. Regular text has a contrast ratio of at least 4.5:1, and large text has a contrast ratio of at least 3:1. In addition, text can be resized up to 200 percent without causing issues with the website.

As I mentioned above, under each WCAG 2.1 principle is a list of guidelines, and under each guideline are compliance standards, with techniques and failure examples at each level. Some guidelines include only Level A items; others include items for multiple levels of conformance, building from A to AAA. At each stage, you can easily see what more you would need to do to reach Level AA or AAA. In this way, many websites include elements at multiple levels of accessibility.

Title III of the Americans with Disabilities Act (ADA) requires that businesses and nonprofit services providers make accessibility accommodations to enable the disabled public to access the same services as clients who are not disabled. This includes electronic media and web sites. While the ADA applies to businesses with 15 or more employees, even smaller businesses can benefit from ensuring that their websites are ADA compliant. Doing so opens your company up to more potential clients and limits liability. Web developers should include ADA compliant features in the original site and application plans.