Male Reproduction COVID Sequelae Study (MARCOS).
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The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT04665258 |
Recruitment Status :
Recruiting
First Posted : December 11, 2020
Last Update Posted : December 16, 2022
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Condition or disease |
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Infertility, Male |
Study Type : | Observational |
Estimated Enrollment : | 160 participants |
Observational Model: | Case-Only |
Time Perspective: | Prospective |
Official Title: | Corona Virus Disease 19 (COVID-19) Vaccine and Impact on Fertility Study |
Actual Study Start Date : | December 14, 2020 |
Estimated Primary Completion Date : | July 14, 2023 |
Estimated Study Completion Date : | July 14, 2023 |

Group/Cohort |
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COVID-19 vaccine group
Participants scheduled to receive the COVID-19 vaccine will be evaluated on its effect on semen parameters for up to 6 months post vaccination.
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- Sperm concentration [ Time Frame: up to 6 months ]As measured from semen samples.
- Sperm motility [ Time Frame: up to 6 months ]As measured from semen samples.

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 18 Years to 50 Years (Adult) |
Sexes Eligible for Study: | Male |
Accepts Healthy Volunteers: | Yes |
Sampling Method: | Probability Sample |
Inclusion Criteria:
- Receiving COVID-19 vaccines
- Male age 18-50 years old
Exclusion Criteria:
- Adults unable to consent
- Women
- Prisoners
- Men who have been receiving Testosterone replacement therapy or anabolic steroids within the last year
- Men with a history of Azoospermia
- Men with a genetic or other medical condition known to be associated with decreased semen parameters (i.e. Klinefelter's syndrome, Y-Chromosome Microdeletion (YCMD), post-chemotherapy treatment, etc.)
- Positive COVID-19 test within the last 3 weeks

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04665258
Contact: Manuel Molina, MD | 3052434873 | m.molina.leyba@miami.edu |
United States, Florida | |
University of Miami | Recruiting |
Miami, Florida, United States, 33136 | |
Contact: manuel molina, md 305-243-4873 m.molina.leyba@miami.edu | |
Principal Investigator: Ranjith Ramasamy, MD |
Principal Investigator: | Ranjith Ramasamy, MD | University of Miami |
Responsible Party: | Ranjith Ramasamy, MD, Associate Professor, University of Miami |
ClinicalTrials.gov Identifier: | NCT04665258 |
Other Study ID Numbers: |
20201451 |
First Posted: | December 11, 2020 Key Record Dates |
Last Update Posted: | December 16, 2022 |
Last Verified: | December 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
COVID-19 Vaccine |
Infertility Infertility, Male |