Axes of social inequities in COVID-19 clinical trials: A systematic review

Front Public Health. 2023 Feb 14:11:1069357. doi: 10.3389/fpubh.2023.1069357. eCollection 2023.

Abstract

Objective: The representativeness of participants is crucial to ensure external validity of clinical trials. We focused on the randomized clinical trials which assessed COVID-19 vaccines to assess the reporting of age, sex, gender identity, race, ethnicity, obesity, sexual orientation, and socioeconomic status in the results (description of the participants' characteristics, loss of follow-up, stratification of efficacy and safety results).

Methods: We searched the following databases for randomized clinical trials published before 1st February 2022: PubMed, Scopus, Web of Science, and Excerpta Medica. We included peer-reviewed articles written in English or Spanish. Four researchers used the Rayyan platform to filter citations, first reading the title and abstract, and then accessing the full text. Articles were excluded if both reviewers agreed, or if a third reviewer decided to discard them.

Results: Sixty three articles were included, which assessed 20 different vaccines, mainly in phase 2 or 3. When describing the participants' characteristics, all the studies reported sex or gender, 73.0% race, ethnicity, 68.9% age groups, and 22.2% obesity. Only one article described the age of participants lost to follow-up. Efficacy results were stratified by age in 61.9%, sex or gender in 26.9%, race and/or, ethnicity in 9.5%, and obesity in 4.8% of the articles. Safety results were stratified by age in 41.0%, and by sex or gender in 7.9% of the analysis. Reporting of gender identity, sexual orientation or socioeconomic status of participants was rare. Parity was reached in 49.2% of the studies, and sex-specific outcomes were mentioned in 22.9% of the analysis, most of the latter were related to females' health.

Conclusions: Axes of social inequity other than age and sex were hardly reported in randomized clinical trials that assessed COVID-19 vaccines. This undermines their representativeness and external validity and sustains health inequities.

Keywords: LGBT; SARS-CoV-2; disparities; ethnic and racial minorities; intersectionality; sexual and gender minorities; social determinants of health.

Publication types

  • Systematic Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19 Vaccines / immunology
  • COVID-19* / epidemiology
  • COVID-19* / prevention & control
  • Clinical Trials as Topic*
  • Diversity, Equity, Inclusion*
  • Ethnicity
  • Female
  • Gender Identity
  • Humans
  • Male

Substances

  • COVID-19 Vaccines

Grants and funding

This work was supported by the Agency for Management of University and Research Grants – AGAUR (grant number 2017 SGR1146), by Carlos III Health Institute and European Union ERDF funds (European Regional Development Fund) through the Research Network in Preventive Activities and Health Promotion in Primary Care (redIAPP, RD16/0007/0001), and the Carlos III Institute of Health, Ministry of Economy and Competitiveness (Spain), awarded on the call for the creation of Health Outcomes-Oriented Cooperative Research Networks (RICOR), with reference (RD21/0016/0001, RD21/0016/0029), co-funded with European Union – NextGenerationEU funds.