One vaccine dose enough for COVID survivors? new study investigates

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. 18 to 45 years old or at least 65 years old, 2. Healthy adults or stable medical condition for adults with pre-existing medical conditions. A stable medical condition is defined as disease not requiring significant change in therapy or hospitalization for worsening disease during 3 months before enrolment, nor expected to require any significant change in therapy or hospitalization for worsening disease in foreseeable future. 3. Group 1: Healthy adults with no previous history of SARS COV2 infection (PCR-, antigenic test- or chest TDM- or serology SARS-CoV-2-) Group 2: Healthy adults with history of infection with SARS COV 2 (PCR+, antigenic test+ or chest TDM+ or serology SARS-CoV-2 of more than 5 months) OR have been a household contact subject and have presented COVID-19 symptoms \[Experienced at least TWO of the following systemic symptoms: Fever (≥ 38ºC), chills, myalgia, headache, sorethroat, new olfactory and taste disorder(s), gastrointestinal symptoms (diarrhea and/or vomiting) or at least ONE of the following respiratory signs/symptoms: cough, shortness of breath or difficulty breathing, OR clinical or radiographical evidence of pneumonia\] since at least 5 months ago and have had a positive SARS-CoV-2 serology between this episode and pre-inclusion. 4. A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies: * Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be post-menopausal for at least 1 year or surgically sterile. OR * Is of childbearing potential and agrees to use an effective contraceptive method from at least 4 weeks prior to vaccination until at least 4 weeks after the last vaccination. A participant of childbearing potential must have a negative blood pregnancy test at enrolment visit. 5. Understands and agrees to comply with the study procedures (visits, phone calls) based on Investigator judgement 6. Written and informed consent signed by the person and the investigator (no later than the day of pre-inclusion and prior to any examination realized in the frame of the trial) (article L1122-1-1 of the Public Health Code) 7. Affiliated or beneficiary of a social security scheme (article L1121-11 of the Public Health Code) (AME is not a social security scheme) 8. who agrees to be registered in the national file of persons who lend themselves to biomedical research (article L1121-16 of the Public Health Code). Exclusion Criteria: 1. Participant is ill or febrile (body temperature ≥ 38.0°C) within 72 prior hours or and/or symptoms suggestive of COVID-19 or being contact subject within the past 14 days at enrolment visit. (Ill or febrile participants may be re-scheduled within the trial inclusion period when no longer presenting symptoms, except if condition is COVID19) 2. Participants with positive PCR, antigenic test or chest TDM or serology to SARS-CoV-2 at the enrolment visit, only for the group1. 3. Participants who already received another anti-SARS-CoV-2-vaccine 4. Participants who received BCG given within the last year. 5. Use of immunosuppressive drugs like e.g. corticosteroids at a dosage \> 10mg equivalent prednisone /day (excluding topical preparations and inhalers) within 3 months prior to enrolment or 6 months for chemotherapies 6. Received immunoglobulin or other blood product within 3 months prior to enrolment or planned receipt of immunoglobulin or a blood product through study completion. 7. Received any vaccination within 4 weeks prior to first injection or plan to receive a licensed vaccine within 4 weeks after the last injection. 8. History of severe adverse reactions to vaccine administration, including anaphylaxis and related symptoms, such as rash, respiratory difficulty, laryngeal oedema and abdominal pain to vaccines, or history of allergic reaction likely to be exacerbated by any component of the anti-SARS-CoV-2-vaccine. 9. History of severe allergic event 10. Known HIV, active HCV or HBV infection 11. Any pathological condition, such as cancer, which may be susceptible of reducing immunity response 12. Any bleeding disorder considered as contraindication to intramuscular injection or phlebotomy 13. The use of investigational Ig, investigational monoclonal antibodies or convalescent serum are not allowed during the study 14. Any condition which in the opinion of the investigator may interfere with the aim of the study 15. Pregnant or breastfeeding or positive pregnancy blood test at enrolment visit. 16. An immediate family member or household member of study staff. 17. Participation in another investigational clinical study (Jardé 1 or Jardé 2) within 4 weeks before the enrolment visit or still in an exclusion period from another clinical trial or participation in another investigational clinical study planned before the study completion. 18. People under legal protection measure (tutorship, curatorship or safeguard measures)