A Study of Ad26.COV2.S in Healthy Pregnant Participants (COVID-19) (HORIZON 1)

An Open-label, Phase 2 Study to Evaluate the Safety, Reactogenicity, and Immunogenicity of Ad26.COV2.S in Healthy Pregnant Participants

The purpose of this study is to assess the safety and reactogenicity of Ad26.COV2.S administered intramuscularly (IM) as a 1-dose schedule at the standard dose level in adult participants during the second and/or third trimester of pregnancy and (potentially) post-partum; to assess the humoral immune response in peripheral blood of adult participants to Ad26.COV2.S administered IM as a 1-dose schedule during the second and/or third trimester of pregnancy, 28 days after vaccination.

Study Overview

• Status: Completed
• Conditions: COVID-19 Prevention
• Intervention / Treatment: Biological: Ad26.COV2.S

Detailed Description

There is an increased risk of severe coronavirus disease-2019 (COVID-19) during pregnancy, as well as an increased risk of adverse birth outcomes. Therefore, the aim of this study is to assess the safety, reactogenicity and immunogenicity of Ad26.COV2.S in adult participants in the second and/or third trimester of pregnancy. Ad26.COV2.S (also known as Ad26COVS1) is a monovalent vaccine composed of a recombinant, replication incompetent adenovirus type 26 (Ad26) vector, constructed to encode the S protein derived from a severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) clinical isolate, stabilized in its prefusion conformation. For each adult participant, the total study duration from screening until the last follow-up visit will be approximately 16 months. The study will consist of a screening phase (28 days), vaccination period (study period from vaccination to pregnancy completion/termination) and a follow-up period (up to 12 months post pregnancy completion/termination). For neonates/infants born to the participants in the study will be followed for approximately 12 months postpartum. Safety assessments will include immunogenicity assessments, physical examination, vital signs, clinical safety laboratory assessments, medical, obstetric and delivery history, pregnancy outcome, neonate safety assessment, adverse events (AEs), serious adverse events (SAEs), and adverse events of special interest (AESI).

• Study Type: Interventional
• Enrollment (Actual): 51
• Phase: Phase 2

Expanded Access

No longer available outside the clinical trial. See expanded access record.

Contacts and Locations

Study Locations

• Brazil
  • Belo Horizonte, Brazil, 30130-100
    • Universidade Federal De Minas Gerais - Hospital das Clínicas
  • Criciúma, Brazil, 88811-508
    • Sociedade Literaria e Caritativa Santo Agostinho Hospital Sao Jose
  • Marilia, Brazil, 17525-160
    • Associacaode Ensino de Marilia LTDA - UNIMAR - Universidade de Marilia
  • Natal, Brazil, 59025-050
    • Centro de Estudos e Pesquisas em Moléstias Infecciosas - CEPCLIN
  • Porto Alegre, Brazil, 90035-903
    • Hospital das Clinicas de Porto Alegre
  • Porto Alegre, Brazil, 90430-001
    • NPCRS Nucleo de Pesquisa Clinica do Rio Grande do Sul
  • Sao Bernardo do Campo, Brazil, 09715-090
    • CEMEC - Centro Multidisciplinar de Estudos Clínicos
  • Sao Jose do Rio Preto, Brazil, 15090-000
    • Fundacao Faculdade Regional de Medicina de Sao Jose do Rio Preto Hospital de Base
  • Sorocaba, Brazil, 18040-425
    • CMPC - Consultoria Médica e Pesquisa Clínica
  • São Paulo, Brazil, 4534002
    • Clinical Research College
• South Africa
  • Dennilton, South Africa, 0485
    • Ndlovu Elandsdoorn Site
  • Johannesburg, South Africa, 2001
    • Shandukani Research Centre
  • Mamelodi East, South Africa, 0122
    • Stanza Clinical Research Centre : Mamelodi
  • Soweto, South Africa, 1864
    • Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital
• United States
  • Mississippi
    • Gulfport, Mississippi, United States, 39503
      • MedPharmics, LLC
  • Nebraska
    • Norfolk, Nebraska, United States, 68701
      • Meridian Clinical Research, LLC
  • New Mexico
    • Albuquerque, New Mexico, United States, 87102
      • MedPharmics, LLC
  • Texas
    • League City, Texas, United States, 77573
      • Maximos Ob/Gyn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• If on medication for a condition, the medication dose must have been stable for at least 4 weeks preceding vaccination
• Participant must be healthy as confirmed by medical history, physical examination, vital signs, and obstetric history performed at Screening. Participant may have underlying illnesses, as long as the symptoms and signs are medically controlled
• Participant will be at second or third trimester of pregnancy, that is, Week 16 to Week 38 of gestation (inclusive), at the time of vaccination, based on ultrasound at the time of screening (or not longer than 10 days prior to vaccination if performed elsewhere)
• Participant agrees to not donate bone marrow, blood, and blood products from the first study vaccine administration until 3 months after receiving the last dose of study vaccine
• Participant must be willing to provide verifiable identification, has means to be contacted and to contact the investigator during the study
• Participant either received their last COVID-19 vaccination with an authorized/licensed COVID-19 vaccine (at least 4 months prior to first study vaccination) or is COVID 19 vaccine-naïve

Exclusion Criteria:

• Participants with medical or obstetric histories that put them at higher risk for maternal or fetal complications (example, chronic pregnancy-related disorders, birth defects or genetic conditions during previous pregnancy)
• Participant with abnormal pregnancy screening test (example, ultrasound fetal abnormalities, maternal blood screen)
• Participant has a history of malignancy within 2 years before screening (exceptions are squamous, basal cell carcinomas of the skin, carcinoma in situ of the cervix, or malignancy, considered cured with minimal risk of recurrence)
• Participant has a known or suspected allergy or history of anaphylaxis or other serious adverse reactions to vaccines or their excipients (including specifically the excipients of the study vaccine)
• Participant has a history of any serious, chronic, or progressive neurological disorders or seizures including Guillain-Barre syndrome, with the exception of febrile seizures during childhood
• Participant has a positive diagnostic test result (polymerase chain reaction [PCR] based viral ribonucleic acid [RNA] detection) severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection at screening or Day 1 (if more than 4 days in between)
• Participant has a history of thrombosis with thrombocytopenia syndrome (TTS), including cerebral venous sinus thrombosis (CVST), or heparin-induced thrombocytopenia (HIT)
• Participant has a history of capillary leak syndrome (CLS)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Groups 1-4: Ad26.COV2.S (One Dose); Participants who are previously vaccinated (Group 1-3) and participants who are vaccine naïve (Group 4) will receive single dose of Ad26.COV2.S vaccine at standard dose level on Day 1. Participants from group 4 who are no longer pregnant may receive single booster dose of Ad26.COV2.S vaccine at standard dose level.	Biological: Ad26.COV2.S; Participants will receive intramuscular (IM) injection of Ad26.COV2.S.; Other Names: JNJ-78436735, Ad26COVS1

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Adult Participants With Solicited Local Adverse Events (AEs) for 7 Days Post First Vaccination	Number of adult participants with solicited local AEs for 7 days post first vaccination was reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Solicited AEs were used to assess the reactogenicity of the study vaccine and were pre-defined as local (at the injection site) AEs for which participants were specifically asked and which were noted by participants in their reactogenicity diary for 7 days post first vaccination (day of first vaccination and the subsequent 7 days). Solicited local AEs are injection site pain/tenderness, erythema, swelling at the vaccination site.	From first vaccination on Day 1 up to 7 days post first vaccination (up to Day 8)
Number of Adult Participants With Solicited Systemic AEs for 7 Days Post First Vaccination	Number of adult participants with solicited systemic AEs for 7 days post first vaccination was reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Solicited AEs were used to assess the reactogenicity of the study vaccine and were predefined as systemic AEs for which participants were specifically asked and which were noted by participants in their reactogenicity diary for 7 days post first vaccination. Participants were instructed on how to note signs and symptoms in the diary on a daily basis for 7 days post first vaccination (day of first vaccination and the subsequent 7 days) for the following solicited systemic AEs: fatigue, headache, nausea, myalgia.	From first vaccination on Day 1 up to 7 days post first vaccination (up to Day 8)
Number of Adult Participants With Unsolicited AEs for 28 Days Post First Vaccination	Number of adult participants with unsolicited AEs for 28 days post first vaccination was reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Unsolicited AEs were defined as AEs for which the participants were not specifically questioned in the participant's reactogenicity diary.	From first vaccination on Day 1 up to 28 days post first vaccination (up to Day 29)
Number of Adult Participants With Serious Adverse Events (SAEs) From First Vaccination Until End of the Study (EOS)	Number of adult participants with SAEs from first vaccination until EOS were reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. SAEs were defined as any untoward medical occurrence that at any dose results in any of the following outcomes: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly/birth defect; suspected transmission of any infectious agent via a medicinal product or medically important.	From first vaccination on Day 1 until end of study (up to post-partum [PP] Day 366 [Day 15 up to Day 554])
Number of Adult Participants With Adverse Events of Special Interest (AESIs) From First Vaccination Until EOS	Number of adult participants with AESIs from first vaccination until EOS were reported. Thrombosis with thrombocytopenia syndrome (TTS) in adults was considered an AESI in this study. TTS is a syndrome characterized by a combination of both a thrombotic event and thrombocytopenia.	From first vaccination on Day 1 until end of study (up to PP Day 366 [Day 15 up to Day 554])
Number of Adult Participants With Medically Attended Adverse Events (MAAEs) Until 6 Months Post First Vaccination	Number of adult participants with MAAEs until 6 months post first vaccination was reported. MAAEs were defined as AEs with medically attended visits including hospital, emergency room, urgent care clinic, or other visits to or from medical personnel for any reason. Routine study visits were not considered medically attended visits. New onset of chronic diseases was collected as part of the MAAEs.	From first vaccination on Day 1 until 6 months post first vaccination (up to Day 183)
Number of Adult Participants With AEs Leading to Study Discontinuation	Number of adult participants with AEs leading to study discontinuation were reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. All AEs leading to discontinuation from the study (regardless of the causal relationship) were reported for all adult participants from the moment of first vaccination until completion of the participant's last study-related procedure.	From first vaccination on Day 1 until end of study (up to PP Day 366 [Day 15 up to Day 554])
Serological Response to Vaccination as Measured by S-Enzyme-linked Immunosorbent Assay (S-ELISA) in Adult Participants 28 Days Post First Vaccination	Serological response to vaccination as measured by S-ELISA in adult participants 28 days post first vaccination was reported.	28 days post first vaccination on Day 1 (at Day 29)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Group 4: Number of Adult Participants With Solicited Local AEs for 7 Days Post Booster Vaccination	Number of adult participants with solicited local AEs for 7 days post booster vaccination was reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Solicited AEs were used to assess the reactogenicity of the study vaccine and were pre-defined as local (at the injection site) AEs for which participants were specifically asked and which were noted by participants in their reactogenicity diary for 7 days post booster vaccination (day of booster vaccination and the subsequent 7 days). Solicited local AEs are: injection site pain/tenderness, erythema, swelling at the vaccination site.	7 days post booster vaccination (Day 84 up to Day 371)
Group 4: Number of Adult Participants With Solicited Systemic AEs for 7 Days Post Booster Vaccination	Number of adult participants with solicited systemic AEs for 7 days post booster vaccination was reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Solicited AEs were used to assess the reactogenicity of the study vaccine and were predefined as systemic AEs for which participants were specifically asked and which were noted by participants in their reactogenicity diary for 7 days post booster vaccination. Participants were instructed on how to note signs and symptoms in the diary on a daily basis for 7 days post-vaccination (day of booster vaccination and the subsequent 7 days) for the following solicited systemic AEs: fatigue, headache, nausea, myalgia.	7 days post booster vaccination (Day 84 up to Day 371)
Group 4: Number of Adult Participants With Unsolicited AEs for 28 Days Post Booster Vaccination	Number of adult participants with unsolicited AEs for 28 days post booster vaccination was reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Unsolicited AEs were defined as AEs for which the participants were not specifically questioned in the participant's reactogenicity diary.	28 days post booster vaccination (Day 84 up to Day 392)
Group 4: Number of Adult Participants With SAEs Post Booster Vaccination Until EOS	Number of adult participants with SAEs post booster vaccination until EOS were reported. AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. SAE were defined as any untoward medical occurrence that at any dose results in any of the following outcomes: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly/birth defect; suspected transmission of any infectious agent via a medicinal product or medically important.	From booster vaccination (Day 84 up to Day 364) until EOS (up to PP Day 366 [Day 366 up to Day 554])
Group 4: Number of Adult Participants With AESIs Post Booster Vaccination Until EOS	Number of adult participants with AESI post booster vaccination until EOS were reported. Thrombosis with thrombocytopenia syndrome (TTS) in adults was considered an AESI in this study. TTS is a syndrome characterized by a combination of both a thrombotic event and thrombocytopenia.	From booster vaccination (Day 84 up to Day 364) until EOS (up to PP Day 366 [Day 366 up to Day 554])
Group 4: Number of Adult Participants With MAAEs Until 6 Months Post Booster Vaccination	Number of adult participants with MAAEs until 6 months post booster vaccination were reported. MAAEs were defined as AEs with medically attended visits including hospital, emergency room, urgent care clinic, or other visits to or from medical personnel for any reason. Routine study visits were not considered medically attended visits. New onset of chronic diseases was collected as part of the MAAEs.	6 months post booster vaccination (Day 84 up to Day 546)
Group 4: Number of Adult Participants With AEs Leading to Study Discontinuation Post Booster Vaccination Until EOS	Number of adult participants with AEs leading to study discontinuation post booster vaccination until EOS were reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. All AEs leading to discontinuation from the study (regardless of the causal relationship) were reported for all adult participants from the moment of booster vaccination until completion of the participant's last study-related procedure.	From post booster vaccination (Day 84 up to Day 364) until EOS (up to PP Day 366 [Day 366 up to Day 554])
Number of Adult Participants With Pregnancy Outcomes	Number of adult participants with pregnancy outcomes were reported. Pregnancy outcomes in adult participants included live term birth, live preterm birth, stillbirth, and abortion.	From first vaccination on Day 1 until PP Day 1 (Day 7 up to Day 163)
Number of Adult Participants With Pregnancy Related AEs Throughout Pregnancy	Number of adult participants with pregnancy related AEs throughout pregnancy were reported. Pregnancy related AEs in adult participants were collected based on 2 baseline gestational age groups (adult participants who received vaccination at 16 to 27 weeks [>=16 weeks to <28 weeks] and at 28 to 38 weeks [>=28 weeks to <=38 weeks]) and included gestational hypertension, foetal growth restriction, haemorrhage in pregnancy, polyhydramnios, pre-eclampsia, premature rupture of membranes, preterm premature rupture of membranes, bradycardia foetal, premature baby, amniorrhexis, foetalgrowth restriction, amniotic fluid volume decreased.	From first vaccination on Day 1 until PP Day 1 (Day 7 up to Day 163)
Serological Response to First Vaccination as Measured by S-ELISA in Adult Participants at All Blood Collection Timepoints Post First Vaccination	Serological response to first vaccination as measured by S-ELISA at all blood collection timepoints post first vaccination were reported.	Day 1, Day 29, PP Day 1 (Day 7 up to Day 163), PP Day 183 (Day 189 up to Day 345)
Serological Response to First Vaccination as Measured by Virus Neutralization Assay (VNA) Titers, 28 Days in Adult Participants Post First Vaccination	Serological response to first vaccination measured by VNA titers at 28 days in adult participants post first vaccination was reported. Data were expressed as 50 percent (%) inhibitory concentration (IC50) units.	28 days post first vaccination on Day 1 (at Day 29)
Group 4: Serological Response to Booster Vaccination Measured by Binding (S-ELISA) Antibody Titers in Adult Participants at Blood Collection Time Points Post Booster Vaccination	Serological response to vaccination as measured by binding (S-ELISA) antibody titers in adult participants at blood collection time points post booster vaccination were reported.	Booster Day 1 (Day 84 up to Day 364), Booster Day 29 (Day 112 up to Day 392)
Group 4: Serological Response to Booster Vaccination Measured by Neutralizing (VNA) Antibody Titers in Adult Participants at Blood Collection Time Points Post Booster Vaccination	Serological response to booster vaccination measured by neutralizing VNA antibody titers in adult participants at blood collection time points post booster vaccination were reported. Data were expressed as IC50 units.	Booster Day 1 (Day 84 up to Day 364), Booster Day 29 (Day 112 up to Day 392)
Serological Response to Vaccination as Measured by S-ELISA at Birth (That is, in Cord Blood) and at 2 Months and 6 Months of Age in Neonates and Infants Born to Adult Participants	Serological response to vaccination as measured by S-ELISA at birth (that is, in cord blood) and at 2 months and 6 months of age in neonates and infants born to adult participants were reported.	At birth (postnatal [PN] Day 1 [Day 7 up to Day 163]), 2 months (up to PN Day 61 [Day 67 up to Day 223]) and 6 months (up to PN Day 183 [Day 189 up to Day 345])
Serological Response to Vaccination as Measured by VNA Titers at Birth (That is, in Cord Blood) in Neonates and Infants Born to Adult Participants	Serological response to vaccination as measured by VNA titers at birth (that is, in cord blood) in neonates and infants born to adult participants were reported. Data were expressed as IC50 units.	At Birth (PN Day 1 [Day 7 up to Day 163])
Number of Neonates and Infants With SAEs (Including MIS-C) From Birth Up to 12 Months of Age in Neonates and Infants Born to Adult Participants	An AE is any untoward medical occurrence in participants in the study that does not necessarily have a causal relationship with pharmaceutical/biological agent under study. SAE: any untoward medical occurrence that resulted in following outcomes: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly/birth defect; suspected transmission of any infectious agent via a medicinal product or medically important. MIS-C: a serious and potentially fatal condition in infants and children with SARS-CoV-2, which resulted in inflammation involving multiple organs. Symptoms of MIS-C: persistent fever, fatigue and signs and symptoms including multiorgan systems (cardiac, gastrointestinal, renal, hematologic, dermatologic, neurologic) involvement, elevated inflammatory markers and, in severe cases, hypotension and shock.	From birth (PN Day 1 [Day 7 up to Day 163]) up to 12 months of age (up to PN Day 366 [Day 372 up to Day 528])
Number of Neonates and Infants With AESIs From Birth Until 12 Months of Age in Neonates and Infants Born to Adult Participants	Number of neonates and infants with AESIs from birth until 12 months of age in neonates and infants born to adult participants were reported. TTS is a syndrome characterized by a combination of both a thrombotic event and thrombocytopenia.	From birth (PN Day 1 [Day 7 up to Day 163]) until 12 months of age (up to PN Day 366 [Day 372 up to Day 528])
Number of Neonates and Infants With MAAEs From Birth Until 6 Months of Age in Neonates and Infants Born to Adult Participants	Number of neonates and infants with MAAEs from birth until 6 months of age in neonates and infants born to adult participants were reported. MAAEs were defined as AEs with medically attended visits including hospital, emergency room, urgent care clinic, or other visits to or from medical personnel for any reason. Routine study visits were not considered medically attended visits. New onset of chronic diseases were collected as part of the MAAEs.	From birth (PN Day 1 [Day 7 up to Day 163]) until 6 months of age (up to PN 183 [Day 189 up to Day 345])
Number of Neonates and Infants With AEs Leading to Study Discontinuation From Birth Until Study Discontinuation	Number of neonates and infants with AEs leading to study discontinuation from birth until study discontinuation were reported. An AE is any untoward medical occurrence in participants who does not necessarily have a causal relationship with pharmaceutical/biological agent under study. All AEs leading to discontinuation from the study (regardless of the causal relationship) were reported for all neonates and infants.	From birth (PN Day 1 [Day 7 up to Day 163]) until study discontinuation (until 12 months of age [up to PN Day 366 {Day 372 up to Day 528}])
Number of Neonates and Infants With Different Birth Outcomes From Birth Up to 12 Months of Age	Number of neonates and infants with different birth outcomes from birth until 12 months of age were reported. Neonate/infant outcomes included normal neonate, term neonate with (or without) complications, preterm neonate with (or without) complications, neonatal infection, respiratory distress, congenital anomalies, neonatal death, low birth weight, and small for gestational age.	From birth (PN Day 1 [Day 7 up to Day 163]) up to 12 months of age (up to PN Day 366 [Day 372 up to Day 528])

Collaborators and Investigators

• Sponsor: Janssen Vaccines & Prevention B.V.
• Investigators: Study Director: Janssen Vaccines & Prevention B.V. Clinical Trial, Janssen Vaccines & Prevention B.V.

Study record dates

Study Major Dates

• Study Start (Actual): August 27, 2021
• Primary Completion (Actual): November 24, 2023
• Study Completion (Actual): November 24, 2023

Study Registration Dates

• First Submitted: February 19, 2021
• First Submitted That Met QC Criteria: February 19, 2021
• First Posted (Actual): February 21, 2021

Study Record Updates

• Last Update Posted (Actual): May 25, 2025
• Last Update Submitted That Met QC Criteria: May 22, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Lung Diseases; Pneumonia, Viral; Pneumonia; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; COVID-19
• Other Study ID Numbers: CR108962; 2020-005330-14 (EudraCT Number); VAC31518COV2004 (Other Identifier: Janssen Research & Development, LLC)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The data sharing policy of the Janssen Pharmaceutical Companies of Johnson & Johnson is available at www.janssen.com/clinical-trials/transparency. As noted on this site, requests for access to the study data can be submitted through Yale Open Data Access (YODA) Project site at yoda.yale.edu

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No