Type I IFN autoantibodies underlie chikungunya live-attenuated vaccine encephalitis

A Adrian Gervais (Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children) P Paul Bastard (Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children) Q Qian Zhang M Marie-Christine Jaffar-Bandjee (Associated National Reference Center for Arboviruses, Centre Hospitalier Universitaire-Réunion) L Lucy Bizien (Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children) L Lotfi Dahmane (Service de Maladies infectieuses, Centre Hospitalier Universitaire Félix Guyon) M Marie-Pierre Moiton (Service de Maladies infectieuses, Centre Hospitalier Universitaire Félix Guyon) J Julien Jabot (Intensive Care Unit, Centre Hospitalier Universitaire) R Radj Cally (Department of Intensive Care Medicine, Felix Guyon University Hospital) A Alexis Maillard (Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children) E Etienne Frumence (Associated National Reference Center for Arboviruses, Centre Hospitalier Universitaire-Réunion) X Xavier de Lamballerie (Unité des Virus Émergents (UVE: Aix-Marseille Univ, Università di Corsica, Institut de recherche pour le developpement 190, Inserm 1207, Institut de recherche biomédicale des armées)) Y Yazdan Yazdanpanah (Department of Infectious Diseases, Bichat-Claude Bernard Hospital) J Jérémie Rosain (Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children) A Aurélie Cobat (St Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University) L Laurent Abel (St. Giles Laboratory of Human Genetics of Infectious Diseases, The Rockefeller University) A Anne Puel C Cyril Ferdynus (Centre for Clinical Investigation Clinical Epidemiology (INSERM CIC 1410), Centre Hospitalier Universitaire de La Réunion) Émilie Mosnier (Service de Maladies Infectieuses et Tropicales, Centre Hospitalier Universitaire de La Réunion Sites Sud) P Patrick Gérardin (Centre for Clinical Investigation Clinical Epidemiology (INSERM CIC 1410), Centre Hospitalier Universitaire de La Réunion) S Shen-Ying Zhang (St. Giles Laboratory of Human Genetics of Infectious Diseases, The Rockefeller University) J Jean-Laurent Casanova

Abstract

Human autoantibodies neutralizing type I interferons (IFNs) have emerged as strong, common, and global determinants of a growing number of severe viral diseases, including hypoxemic viral pneumonia, arboviral encephalitis, and adverse reaction to the live-attenuated yellow fever virus (YFV) vaccine. Chikungunya virus (CHIKV) is a growing global health concern that the live-attenuated vaccine VLA1553 (IXCHIQ®) was developed to address. In 2025, five unrelated adults (aged 82 to 88) on the island of La Réunion (France) developed severe reactions postvaccination; two died. The three patients with encephalitis (aged 84 to 85), including one lethal case, had immunoglobulin G autoantibodies in the blood neutralizing high concentrations of both IFN-α and -ω on admission. An 82-y-old survived rhabdomyolysis without encephalitis, and an 88-y-old died during hospitalization following CHIKV infection despite late vaccination; both lacked autoantibodies against type I IFNs. Autoantibodies neutralizing type I IFNs underlie all three cases of live-attenuated CHIKV vaccine encephalitis studied. Individuals with autoantibodies neutralizing type I IFNs should not be inoculated with live-attenuated YFV and CHIKV vaccines.

Article Details

Volume / Issue Vol. 123, Issue 4
Published January 27, 2026
ISSN 0027-8424
Publisher National Academy of Sciences

Authors (22)

A

Adrian Gervais

Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children

P

Paul Bastard

Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children

Q

Qian Zhang

M

Marie-Christine Jaffar-Bandjee

Associated National Reference Center for Arboviruses, Centre Hospitalier Universitaire-Réunion

L

Lucy Bizien

Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children

L

Lotfi Dahmane

Service de Maladies infectieuses, Centre Hospitalier Universitaire Félix Guyon

M

Marie-Pierre Moiton

Service de Maladies infectieuses, Centre Hospitalier Universitaire Félix Guyon

J

Julien Jabot

Intensive Care Unit, Centre Hospitalier Universitaire

R

Radj Cally

Department of Intensive Care Medicine, Felix Guyon University Hospital

A

Alexis Maillard

Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children

E

Etienne Frumence

Associated National Reference Center for Arboviruses, Centre Hospitalier Universitaire-Réunion

X

Xavier de Lamballerie

Unité des Virus Émergents (UVE: Aix-Marseille Univ, Università di Corsica, Institut de recherche pour le developpement 190, Inserm 1207, Institut de recherche biomédicale des armées)

Y

Yazdan Yazdanpanah

Department of Infectious Diseases, Bichat-Claude Bernard Hospital

J

Jérémie Rosain

Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children

A

Aurélie Cobat

St Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University

L

Laurent Abel

St. Giles Laboratory of Human Genetics of Infectious Diseases, The Rockefeller University

A

Anne Puel

C

Cyril Ferdynus

Centre for Clinical Investigation Clinical Epidemiology (INSERM CIC 1410), Centre Hospitalier Universitaire de La Réunion

Émilie Mosnier

Service de Maladies Infectieuses et Tropicales, Centre Hospitalier Universitaire de La Réunion Sites Sud

P

Patrick Gérardin

Centre for Clinical Investigation Clinical Epidemiology (INSERM CIC 1410), Centre Hospitalier Universitaire de La Réunion

S

Shen-Ying Zhang

St. Giles Laboratory of Human Genetics of Infectious Diseases, The Rockefeller University

J

Jean-Laurent Casanova