The Unified COVID-19 Algorithms reflect evidence updates from the Philippine COVID-19 Living Recommendations. Version 4 is now subsumed under the Philippine COVID-19 Living Recommendations initiative in order to streamline the alignment of evidence with decision-making tools. Under this, it is funded by the Department of Health (DOH) AHEAD Program through the DOST-Philippine Council for Health Research and Development (PCHRD) and the DOH-Disease Prevention and Control Bureau (DPCB).

Version 4 is built on the grassroots effort of volunteers from different medical organizations, subject matter experts, stakeholders, as well as end-users. Facilitation was done by technical specialists from the Asia- Pacific Center for Evidence-Based Healthcare (APCEBH), Alliance for Improving Health Outcomes (AIHO), and Kalusugan ng Mag-Ina (KMI). With the Philippine context in perspective, the algorithms provide clear guidance for COVID-19 management from both the community and hospital levels. The development process was framed on evidence-based, patient-centered, and equity-driven principles.

Work on the first release of the Unified COVID-19 Algorithms started as early as March 2020 with representatives from the Philippine Society for Microbiology and Infectious Diseases (PSMID), Philippine College of Physicians (PCP), Philippine Society of General Internal Medicine (PSGIM), and the Philippine Society of Public Health Physicians (PSPHP). The Philippine College of Occupational Medicine (PCOM) and the Philippine College of Emergency Medicine (PCEM) were also among the first medical societies to join us in unifying guidance for colleagues at the frontlines. This collaboration incubated the formation of the Healthcare Professionals Alliance Against COVID-19 (HPAAC).

With continued support from PSMID, expansion was carried out by the HPAAC Steering Committee through its network of volunteers and the leadership of various medical professional societies. Major changes in the latest version include the following:

• All algorithms were streamlined for better clarity and operational feasibility, with equity lens in mind.
• The definitions of COVID-19 severities were updated based on the latest Living CPG.
• A section discussing the implications of the strength of recommendation was added.
• The duration of isolation was revised based on the latest DOH guidelines (DOH DM 2022-0013)accounting for illness severity and vaccination status.
• For severely immunocompromised patients, the need to coordinate specialist care was emphasized.
• Guidance on testing prioritization was added especially in scenarios where resources are limited (e.g., during a surge).
• Recommendations on the use of novel COVID-19 drugs in non-hospitalized settings were added.
• Recommendations on non-pharmacologic interventions for the prevention and control of COVID-19 were added.
• Personal protective equipment (PPE) levels and components were updated based on the latest Living CPG, with consideration of airborne transmission.