Post-COVID Condition Core Outcomes
PC-COS Adults 'How to measure' paper is out!
The study team would like to thank all stakeholders who participated in the consensus process and contributed to the completion of this important project.
PC-COS Project

The Coronavirus disease 2019 (COVID-19) pandemic has necessitated rapid responses from healthcare systems and research networks all over the world. The post-COVID-19 condition, also known as Long-COVID-19 is becoming an important target for research and clinical practice. With an increasing number of studies assessing sequelae of COVID-19, there is a need for a standardised evaluation and reporting of outcomes.

PC-COS project is an international consensus study to develop a standardised set of outcomes – a ‘core outcome set’ (COS) – to be used by all future trials examining outcomes and clinical practice in people with the post-COVID condition.

The project is designed by a group of international experts and members of the public, including people with lived experience of the post-COVID condition, and is supported by WHO.
PC-COS study Q&A on developing
LongCOVID core outcome set

Watch Q&A on developing a core outcome set for
post-COVID condition (LongCOVID) with Dr Margaret O'Hara, a founder Trustee of Long Covid Support and PC-COS project's co-lead Dr Tim Nicholson

Our aim

On behalf of the Post-COVID Core Outcome Set (PC-COS) group and the World Health Organization (WHO), we seek to create a core set of outcomes that should be evaluated in all research studies and in clinical care for people with Post-COVID condition (also known as Long-COVID or Post-Acute Sequelae of SARS-CoV-2 infection).

The PC-COS project aims to bring together different people affected by the Post-COVID Condition - people with lived experience and their carers, health professionals, researchers, and policymakers - to establish a consensus-based list of the most important outcomes that should be consistently included in research studies and used in clinical practice.
PC-COS Project involves various stakeholder groups to ensure the perspectives of people with Post-COVID Condition, their family members as well as health professionals and others involved in their care are considered.

Types of PC-COS project participants:
  • People with Long COVID/Post-COVID Condition
  • Family members/caregivers of people with Long COVID/Post-COVID Condition
  • Health professionals with Long COVID/Post-COVID Condition
  • Researchers with Long COVID/Post-COVID Condition
  • Health professionals (including those who also do research)
  • Researchers (without any clinical patient care duties)
  • Other (policymakers, etc.)
Why are we doing this study?
Currently, there is no standardised approach for evaluating health and wellbeing of people with Post-COVID Condition. The absence of universally agreed outcomes to measure in people with long COVID causes different researchers and health professionals around the world to measure different outcomes. Hence, the results of the studies cannot be easily compared, potentially slowing the improvements in clinical care. This study aims to find the outcomes that are essential to measure in research and clinical care. These outcomes are called core outcomes and will be included in a core outcome set.

What is COS?

When the health of an individual is evaluated, it is very important to know what effects of a condition are the most important and may affect their life the most. The same essential features inform the treatment testing and research. In this project, we want to investigate which features, or outcomes, are the most important in Post-COVID Condition.

We want to know which outcomes are the most important and should be included in all future research studies and clinical care of Post-COVID Condition. It is important to note that once the core outcome set is developed this does not mean that other outcomes cannot be measured too. The core outcome set aims to ensure that the most important outcomes are measured in every study and in clinical care.

A video developed by Core Outcome Measures in Effectiveness Trials (COMET) initiative explains what core outcome sets are, why they are important, and how patients and the public are involved in developing COS.

Subtitles in French, Portugese, Dutch, Chinese, German, Spanish, Greek, Italian, Hungarian, Russian, Swedish and Bangala are available.
Reaching consensus
PC-COS project will use a method called 'Delphi Process' to evaluate the views of the participants and reach consensus on what outcomes are the most important. Delphi Process plain language summary developed by COMET initiative explains what outcomes and consensus processes are, and what happens in a Delphi process. You can download the Summary here:
Project information

PC-COS initiative has been registered within the Core Outcome Measures in Effectiveness Trials (COMET) Initiative:
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