Neutralizing Power of Serum Antibodies - 2 (PNAS-2)

Study of the Neutralizing Power of Serum Antibodies - 2 (PNAS-2)

Severe forms of COVID-19 and Monkeypox affect immunocompromised and comorbid individuals. Vaccination and monoclonal antibody therapies induce neutralizing antibodies. This neutralizing power is recognized as a correlate of protection against a new infection. This study aims to describe the neutralizing power of serum and nasal antibodies over time, in relation to SARS-CoV-2 and MPXV vaccines or treatments received.

Study Overview

• Status: Recruiting
• Conditions: COVID-19; Monkey Pox; Serum; Vaccination; Mucosal Immunity; SARS-CoV-2 Viraemia
• Intervention / Treatment: Other: Sample collection (blood and optional nasal swab)

Detailed Description

This is a monocentric, longitudinal, descriptive study aiming to measure and describe the evolution of the humoral immune response (serum and nasal) to SARS-CoV-2 and MPXV, following any vaccination or administration of monoclonal antibodies. Samples are collected over a maximum 60-month period per participant to assess the durability of neutralizing activity.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Thierry PRAZUCK, Dr; Phone Number: +33 0238229593; Email: thierry.prazuck@chu-orleans.fr

Study Locations

• France
  • Orléans, France, 45067
    • Recruiting
    • CHU Orléans
    • Contact: Thierry PRAZUCK, Dr; Phone Number: +33 0238229593; Email: thierry.prazuck@chu-orleans.fr
    • Principal Investigator: Thierry PRAZUCK, Dr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults (≥18 years)
• Patients receiving or scheduled to receive anti-SARS-CoV-2 and/or anti-MPXV vaccines or monoclonal antibodies
• Patients have provided written informed consent

Exclusion Criteria:

• Persons under guardianship or curatorship
• Persons under legal protection,
• Persons persons deprived of liberty
• Persons not affiliated to a social security scheme
• Pregnant or breastfeeding women

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Participants receiving vaccines and/or monoclonal antibodies; Participants receive standard-of-care SARS-CoV-2 and/or MPXV vaccines or monoclonal antibodies. This study does not assign the treatment but collects biosamples to assess antibody response.	Other: Sample collection (blood and optional nasal swab); Venous blood collection (2 tubes of 6 mL) and optional nasal swab at each visit. Aliquots analyzed for neutralizing activity against SARS-CoV-2 and MPXV using validated assays at Institut Pasteur

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum neutralizing antibody evolution (anti-SARS-CoV-2 and anti-MPXV) over time	S-Fuse and S-Flow tests performed on collected serum samples at each visit	Up to 60 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mucosal (nasal) neutralizing antibody response and MPXV serology over time	Nasal antibody neutralization (anti-MPX) and serum MPXV neutralization assessed using validated Pasteur Institute protocols	Up to 60 months
Mucosal (nasal) neutralizing antibody response and SARS-CoV-2 serology over time	Nasal antibody neutralization (anti-SARS-CoV-2) and serum SARS-CoV-2 neutralization assessed using validated Pasteur Institute protocols	Up to 60 months

Collaborators and Investigators

• Sponsor: Centre Hospitalier Régional d'Orléans
• Investigators: Principal Investigator: Thierry PRAZUCK, Dr, CHU Orléans

Publications and helpful links

General Publications

• Grzelak L, Temmam S, Planchais C, Demeret C, Tondeur L, Huon C, Guivel-Benhassine F, Staropoli I, Chazal M, Dufloo J, Planas D, Buchrieser J, Rajah MM, Robinot R, Porrot F, Albert M, Chen KY, Crescenzo-Chaigne B, Donati F, Anna F, Souque P, Gransagne M, Bellalou J, Nowakowski M, Backovic M, Bouadma L, Le Fevre L, Le Hingrat Q, Descamps D, Pourbaix A, Laouenan C, Ghosn J, Yazdanpanah Y, Besombes C, Jolly N, Pellerin-Fernandes S, Cheny O, Ungeheuer MN, Mellon G, Morel P, Rolland S, Rey FA, Behillil S, Enouf V, Lemaitre A, Creach MA, Petres S, Escriou N, Charneau P, Fontanet A, Hoen B, Bruel T, Eloit M, Mouquet H, Schwartz O, van der Werf S. A comparison of four serological assays for detecting anti-SARS-CoV-2 antibodies in human serum samples from different populations. Sci Transl Med. 2020 Sep 2;12(559):eabc3103. doi: 10.1126/scitranslmed.abc3103. Epub 2020 Aug 17.
• Planas D, Bruel T, Grzelak L, Guivel-Benhassine F, Staropoli I, Porrot F, Planchais C, Buchrieser J, Rajah MM, Bishop E, Albert M, Donati F, Prot M, Behillil S, Enouf V, Maquart M, Smati-Lafarge M, Varon E, Schortgen F, Yahyaoui L, Gonzalez M, De Seze J, Pere H, Veyer D, Seve A, Simon-Loriere E, Fafi-Kremer S, Stefic K, Mouquet H, Hocqueloux L, van der Werf S, Prazuck T, Schwartz O. Sensitivity of infectious SARS-CoV-2 B.1.1.7 and B.1.351 variants to neutralizing antibodies. Nat Med. 2021 May;27(5):917-924. doi: 10.1038/s41591-021-01318-5. Epub 2021 Mar 26.
• Hubert M, Guivel-Benhassine F, Bruel T, Porrot F, Planas D, Vanhomwegen J, Wiedemann A, Burrel S, Marot S, Palich R, Monsel G, Diombera H, Gallien S, Lopez-Zaragoza JL, Vindrios W, Taieb F, Fernandes-Pellerin S, Delhaye M, Laude H, Arowas L, Ungeheuer MN, Hocqueloux L, Pourcher V, Prazuck T, Marcelin AG, Lelievre JD, Batejat C, Levy Y, Manuguerra JC, Schwartz O. Complement-dependent mpox-virus-neutralizing antibodies in infected and vaccinated individuals. Cell Host Microbe. 2023 Jun 14;31(6):937-948.e4. doi: 10.1016/j.chom.2023.05.001. Epub 2023 May 5.

Study record dates

Study Major Dates

• Study Start (Actual): August 22, 2025
• Primary Completion (Estimated): August 22, 2030
• Study Completion (Estimated): July 11, 2035

Study Registration Dates

• First Submitted: July 17, 2025
• First Submitted That Met QC Criteria: July 24, 2025
• First Posted (Actual): July 25, 2025

Study Record Updates

• Last Update Posted (Actual): December 19, 2025
• Last Update Submitted That Met QC Criteria: December 12, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: SARS-CoV-2; Serum; Vaccination; Mucosal immunity; Monkeypox; Neutralizing antibodies
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Lung Diseases; Poxviridae Infections; DNA Virus Infections; Pneumonia, Viral; Pneumonia; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; Animal Diseases; Primate Diseases; Rodent Diseases; COVID-19; Mpox, Monkeypox; Investigative Techniques; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative; Specimen Handling; Blood Specimen Collection
• Other Study ID Numbers: CHUO-2024-22

Drug and device information, study documents

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