Number of clinical trial registrations by location, disease, phase of development, age and sex of trial participants
Published: June 2026
The number of trials listed in the WHO International Clinical Trials Registry Platform (ICTRP) is reported by year, location (WHO region and country), disease (or condition), phase of development, age, sex and number of participants. Note that the ICTRP comprises both interventional and observational trials. See more on the scope of the ICTRP below.
See also:
What you see | Scope and limitations | Data sources | Previous versions
What you see
The data visualization above shows the number of trials listed on the ICTRP from 1999 to June 2026 by:
- year, worldwide (chart A)
- phase of development (chart B)
- year and WHO region (chart C)
- health category (chart D)
- country or area (chart E; colour coded by WHO region)
- sex of trial participants (chart F)
- age and life stage grouping of trial participants (chart G1 and G2)
- number of trial participants (chart H)
Chart A shows the total number of trials, regardless of the number of trial sites involved. A multicountry trial is counted once for each participating region in chart C but once for each participating country in chart E. The default for other charts is one trial counted once regardless of the number of sites. When a selection is made, either by filtering a region or country, the count will reflect the same principle described above. The year corresponds to the date of enrollment of the first trial participant; in a small number of cases when this is not available the registration year is used. With respect to age of trial participants, charts G1 and G2 count trials once for each age group in their inclusion criteria.
The data can be visualized separately for interventional or observational trials by selecting the relevant tick box at the top left of the visualization. With respect to disease or conditions focus, trials on ' neglected tropical diseases' or ' R&D Blueprint pathogens', or 'trials on pregnant women or pregnancy-related trials' can also be viewed separately (select desired options using the circular buttons at the top left or top right of the data visualization).
Points to note:
- The United States of America had the highest total number of trials registered during 1999-June 2026 (208,615), followed by China (197,835) and India (118,722, 20,000 more compared to last year again - select India in E to view cumulative number of trials in A and trials per year in C) (chart E).
- If we look only at trials registered since 2019 China has 127,650; India has 76,125; and the United States of America has 71,401. Between 20,000 and 30,000 trials have been registered in each of Japan, Germany, France and Iran (Islamic Republic of) in this time frame (Go to Chart A and select each year on the line graph, while holding down control to select multiple years)
- Of trials with an identified phase of development, the largest number of trials is in phase II (128,925) (chart B).
- Data mining techniques were used to assign a primary disease to each trial (see approach under analysis below). It was not possible to match 257,041 trials (23%) to any disease. For some trials, it was only possible to classify them into broader categories.
- Of the trials that were categorized into a disease or condition, 81% were for noncommunicable diseases, 14% for communicable, maternal, perinatal and nutritional conditions, and 3% for injuries (chart D).
- Among the trials on the R&D Blueprint pathogens (tick the corresponding box at the top right to filter), the top three were on COVID-19 (13,811, only around 60 new trials in the last year), severe acute respiratory syndrome (238) and Ebola virus disease (149) (chart D.2). In trials registered in 2025 (click on year in A) the top 3 disease targets were COVID-19 (195), Ebola virus disease (7) and Crimean-Congo heamorrhagic fever (3).
- Of all trials, most (74%) included both males and females (chart F).
- Of all trials, most (91%) included adults in their inclusion criteria while 30% included children; this information was unknown in 0.02% of trials (chart G1). Of the trials that specified children in their inclusion criteria, just over 80% were open to neonates in the early or late neonatal periods, (select children in G1 and hover the cursor on the corresponding bar in chart G2 and see information in the popup window).
To explore the data further
- Tick the box (top left) to filter the results for only interventional or observational trials.
- To filter the results for one or a combination of the following: year, WHO region, country or area, phase of development, disease or condition, or participant number, click on the relevant data element (for example on a region from the key in chart C; a point on the trend line for the year; or a bar beside the country, phase or disease of interest) in the relevant charts.
-- For any of the above selections, information in the other charts will update accordingly, as relevant. - Hover the cursor on a data element of interest (for example a bar or a point on a trend line) to see more information in a popup window.
- Hold the Ctrl key to select more than one option, for example two regions.
- Undo a selection by clicking ‘undo’ or ‘reset’ near the bottom of the page or by clicking the same element again.
Analysis and limitations of the data analysis
Data cleaning and standardisation
The ICTRP data contain inconsistencies and missing information. Data cleaning was therefore undertaken to standardise the information wherever possible. However, some information remained unavailable, such as the country in which a trial was conducted or its phase of development.
Classification of diseases and conditions
Automated text analysis was used to identify the primary disease or condition investigated in each trial. For the 2026 data update, the following approach was used:
- Creating a list of disease names: A list of disease names and synonyms was compiled using the Unified Medical Language System (UMLS) and the International Classification of Diseases (ICD). Additional terms were identified from the trial records to account for variations in terminology, abbreviations and spelling errors.
- Matching diseases to trial records: An automated algorithm was used to identify diseases or conditions by searching two fields in each trial record. The algorithm searched the condition field first. If a match was found, the scientific title was not searched:
- Condition: Free-text information provided by the person registering the trial.
- Scientific title: The full scientific title of the trial.
- Selecting the primary disease: Previously, the first disease identified by the algorithm was selected as the primary disease investigated. For the 2026 update, the matching process was refined to rank identified diseases according to the similarity between the terms recorded in the trial and the disease names in the reference list. The closest match was selected as the primary disease.
- Limitations: Some trials investigate more than one disease or condition. However, this analysis assigns only one primary disease or condition to each trial. Although the algorithm was refined through several rounds of testing, some trials may still have been incorrectly classified.
Further details of the methodology are available in Resource allocation for biomedical research: analysis of investments by major funders.
Overall, a disease or condition could be identified for 77% of all trials included in the analysis. The remaining 23% could not be assigned a disease or condition using this method.
How trials are counted in the charts
Some classifications are not mutually exclusive, meaning that a trial may be counted in more than one category.
Geographical distribution (Charts C and E)
A trial may recruit participants from several countries or regions. In Chart C, each trial is counted once per region, whereas in Chart E, it is counted once per country.
For example, a trial conducted in Kenya, Uganda and France would be counted twice in Chart C (once for Africa and once for Europe), but three times in Chart E (once for each country).
Consequently, the totals across the two charts may differ and should not be directly compared.
Age groups and life stages (Charts G1 and G2)
Trials are classified according to the age groups and life stages included in their eligibility criteria, using the standardized age-disaggregation classification.
Age groups refer to specific age ranges (e.g., 0–4, 5–9 or 10–14 years), while life stages represent broader categories such as children, adolescents, adults and older adults.
A trial covering multiple age groups or life stages is counted once in each relevant category. Consequently, the sum of trials across categories may exceed the total number of unique trials.
Data updates and limitations
This analysis will be updated regularly. However, delays may occur between updates to the original data sources and updates to this visualisation.
The underlying registry data may contain missing, incomplete or inaccurate information. Although data cleaning and standardisation were undertaken to improve consistency, some errors may remain, and the automated classification process may introduce additional inaccuracies.
The accuracy and completeness of the original information remain the responsibility of the data providers. Please see terms and conditions of use.