Monkeypox Virus Infection in Newborns | NEJM

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The ongoing monkeypox outbreak was recently declared a Public Health Emergency of International Concern by the World Health Organization.¹ Young children are at serious risk of disease; Therefore, early detection and prompt treatment are important.²

Illustration 1. Illustration 1. Monkeypox skin lesions in a newborn.

Shown are monkeypox skin lesions on the hands and feet of a newborn. Visible lesions range from vesicles to pustules, and lesions that have begun to scab are also shown. Photographs were obtained on day 5 after rash onset.

We report a case of perinatally acquired monkeypox virus infection and adenovirus co-infection in a 10-day-old infant. After the uneventful birth of the infant at the end of April 2022, a skin rash developed on the 9th day of life. The rash was initially vesicular, starting on the palms and soles of the feet and then spreading to the face and trunk, gradually becoming pustular (illustration 1). Nine days before the birth, the child’s father had a feverish illness followed by a widespread rash; the rash disappeared before the child was born. Four days after the birth of the child, the mother developed a similar rash. The family lived in the UK and there was no trip to Africa or contact with travelers.

The infant was transferred to the regional pediatric intensive care unit at day 15 due to developing hypoxemic respiratory failure (Fig. S1 in the Supplementary Appendix, available with the full text of this letter at NEJM.org). A range of diagnoses (neonatal chickenpox, herpes simplex virus infection, coxsackievirus or enterovirus infection, staphylococcal skin infection, scabies, syphilis and gonorrhea) were considered. The presence of axillary lymphadenopathy, the nature of the skin lesions, and the atypical time course of intrafamilial infection raised concerns about human monkeypox. Polymerase chain reaction testing of blood, urine, blister fluid, and throat swab samples from the infant and mother resulted in a diagnosis of monkeypox virus (clade IIb) infection. Adenovirus was also identified in the infant’s respiratory secretions and blood. The infant’s condition deteriorated and invasive ventilation was instituted. Enteral tecovirimate (at a dose of 50 mg twice daily) in combination with intravenous cidofovir was initiated for 2 weeks. After 4 weeks in the ICU, including 14 days on invasive ventilation, the infant recovered and was discharged home. The timeline of intrafamilial infection and test results is shown in Figure S2.

Reports of neonatal infection with monkeypox virus are rare.³ This was a case of neonatal monkeypox virus infection after peripartum transmission within a family cluster; A transplacental transmission could not be excluded.⁴ Since this was an isolated case, it is not possible to assign the clinical disease directly to any of the pathogens (monkeypox virus or adenovirus), nor to assign the improvement in the infant’s clinical condition to the use of tecovirimate or cidofovir.⁵ Monkeypox virus infection should be considered in the differential diagnosis of neonatal vesicular rash.

Padmanabhan Ramnarayan, MD
Imperial College London, London, United Kingdom
[email protected]

Rebecca Mitting, MB, BS
Imperial College Healthcare NHS Trust, London, United Kingdom

Elizabeth Whittaker, Ph.D.
Imperial College London, London, United Kingdom

Maria Marcolin, MRCPCH
Ciara O’Regan, MRCPCH
Ruchi Sinha, MRCPCH
Aisleen Bennett, Ph.D.
Moustafa Moustafa, MRCPCH
Neil Tickner, M.Pharm.
Mark Gilchrist, MSc
Imperial College Healthcare NHS Trust, London, United Kingdom

Anthony Kershaw, MRCPCH
London Northwest University Healthcare NHS Trust, London, United Kingdom

Tommy Rampling, D.Phil.
UK Health Security Agency, London, United Kingdom

This letter was published on NEJM.org on October 12, 2022.