Travel health is a critical aspect of public health that focuses on the prevention and management of health risks associated with international travel. As international travel increases, the need for effective travel health communication becomes crucial. Health care professionals who specialize in travel health play an essential role in providing evidence-based recommendations and guidance to mitigate health risks and promote safe travel practices among their patients (Yazdian Anari et al., 2015).

The CDC Yellow Book: Health Information for International Travel, commonly referred to as the CDC Yellow Book, is a key travel health resource published by the U.S. CDC. The CDC Yellow Book compiles the U.S. government’s most up-to-date health-related travel recommendations, including pre-travel vaccination guidance and destination-specific advice on managing health risks (CDC, 2024). For decades, the CDC Yellow Book has served as an authoritative resource for health care professionals. In the late 1990s, the CDC adapted the print content into a free companion website to increase the resource’s online reach and allow for more frequent updates of content.

User experience (UX) is a key element in the design of effective public health websites (Hasson et al., 2024; Imlawi, 2017). Successful UX ensures that public health websites are designed using a human-centered approach, solving the problems of the users as well as providing an intuitive interface to access the information needed. In a study conducted by Alqahtani and Orji (2020) on the UX reviews of mental health applications (apps), they found that users placed a high emphasis on the user experience of the app. The study found that poor usability of the app was the most common reason for abandoning the app, emphasizing the importance of UX in health promotion practice. In the context of travel health, a well-designed CDC Yellow Book website has the ability to make critical travel-related health information and recommendations easily accessible to health care professionals.

Since the print content was digitized in the late 1990s, the CDC Yellow Book website has evolved. However, the digitization processes for each edition did not adopt a digital-first approach, an approach that optimizes content for the digital landscape, leading to several UX gaps such as barriers to finding relevant content, poor visual appeal, and inaccessibility on mobile devices. Noting the outdated user interface, the CDC Travelers’ Health Branch implemented a UX update to the CDC Yellow Book 2024 website to address these challenges.

The objective of this case study was to provide an overview of how the UX framework was used for the CDC Yellow Book 2024 website, which includes describing the lessons learned to inform future digitization efforts for health promotion tools.

Health communication specialists within the CDC collaborated with web developers using an iterative design process to improve the website. Wireframes and mockups of various elements from the existing website were developed, incorporating internal feedback from health care professionals who specialize in travel health and health communication specialists. Once consensus was reached on the design, web developers created functional prototypes, which were subsequently reviewed by the same experts and specialists for further input. Once the prototypes were approved, the CDC implemented the UX update on May 10, 2023. This meant that the CDC Yellow Book 2020 website was replaced with the updated CDC Yellow Book 2024 website.

To evaluate the outcomes of these updates, website metrics were collected using Adobe Analytics, a web analytics software, for one year after the update, from May 10, 2023, to May 9, 2024. These metrics were then compared with the data from the year prior to the UX update, covering the period of May 10, 2022, to May 9, 2023. This project did not involve human data or participants; therefore, an Institutional Review Board (IRB) assessment was not necessary per the policy of the CDC.

The UX Honeycomb is a framework used for evaluating and improving the UX for digital platforms and products. Developed by Peter Morville (Semantic Studios, 2004), the framework ensures that UX updates consider and identify opportunities to improve seven essential features: usability, usefulness, credibility, findability, desirability, accessibility, and value. Using features from this framework, the CDC Travelers’ Health Branch implemented the following tactics:

Health care professionals were consulted to obtain the most up-to-date recommendations for over 180 travel health topics to be included as chapters in the publication, an effort to improve usefulness and value. To establish credibility, over 300 authors considered experts in their fields were asked to write new chapters for health care professionals on how to counsel patients based on their possible exposure risks during their travel.

The home page (Figure 1) was redesigned to communicate the brand identity and enhance visual appeal, a tactic to improve desirability. On the home page, the updated design featured the top visited chapters, a map directory, new chapters, and popular travel itineraries. The print publication cover of a kayaker in a Romanian cave was used on the home page to make a strong first impression. In addition, a more visually appealing table of contents was developed, which included banners with high-quality images.

Search engine optimization (SEO) techniques, which are tactics to optimize web content for higher rankings in search engines, were applied. An approach to improve findability, SEO tactics ensured that webpages used strategic travel health keywords that health care professionals would search for online and that the webpages were up-to-date. These tactics help search engines recognize the value of the content to the audience (Loktionova, 2024). To facilitate easy navigation and usability, chapters were structured in scannable formats, featuring quick-access menus at the top of each webpage. Breadcrumbs, a navigational aid used in website design to help users understand the hierarchy of the website structure and their current location, were used. Internal linking between chapter webpages was included to enable users to seamlessly access relevant topics without having to scan the entire website.

A library of data tables, figures, and maps was organized. This approach aimed to address the chronological categorization of the previous version, where resources were listed by their placement in the print version and by their formats (e.g., tables, boxes, maps, figures) rather than by subject matter.

To support accessibility, efforts were made to improve responsive design, which ensures that a website’s content displays appropriately regardless of varying screen sizes such as desktops or mobile devices. For instance, on the CDC Yellow Book 2020 website, the maps appeared appropriately for desktop devices but spilled off the screen for mobile devices. Therefore, the CDC Yellow Book 2024 used a responsive design to ensure maps were also accessible on mobile devices (Figure 2).

The CDC Yellow Book 2024 website received 5,726,545 page views for the year following the UX update, which was a 46% increase in web traffic compared to the CDC Yellow Book 2020 website the year prior to the update. Additionally, there were 2,375,995 users who returned to the CDC Yellow Book 2024 website seven or more days after their first visit. In comparison, the CDC Yellow Book 2020 website had 1,687,653 users return to the website after seven or more days.

The following lessons from implementing a UX framework for a public health website aim to support future digitization efforts in health promotion practice.

These web metrics have several limitations that must be acknowledged. First, the observed web traffic could not be directly linked to the UX updates since a formal study specifically designed to assess the impact of these efforts was not conducted. Second, behavioral factors such as the post-COVID surge in travel may have led more users to the CDC Yellow Book 2024 website. Third, broader technology trends, such as the increasing popularity of mobile device usage for online information access, may have influenced user engagement and session duration.

The UX tactics used on the CDC Yellow Book 2024 website offer valuable insights for future digitization efforts of public health tools. The lessons learned from the implementation of this UX framework underscore the importance of human-centric design and digital-first approaches, particularly in public health products employing both print and digital formats. Public health professionals can use these efforts as a roadmap for building public health websites and digitizing public health tools.